Patent Description:
A humidity measuring device is disclosed in <CIT>. In such a humidity measuring device, the humidity of intake air that flows through a main air passage is measured. An insertion hole is provided in a main air passage wall of the main air passage. The humidity measuring device is inserted into the insertion hole.

The humidity measuring device disclosed in <CIT> does not include a display device on which the humidity of the gas measured by the humidity measuring device is displayed. Thus, a problem arises in that the user is incapable of confirming the humidity of the gas by the humidity measuring device.

<CIT> shows a humidity measuring device including a humidity sensing element, a temperature sensing element and a display unit. <CIT> discloses a dehumidifier comprising a dew point sensor.

The present invention is characterized by claim <NUM>.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which preferred embodiments of the present invention are shown by way of illustrative example.

<FIG> is a view showing a humidity measuring device <NUM>. The humidity measuring device <NUM> includes a casing <NUM> and a display unit <NUM>. In <FIG>, a cross-sectional view of the casing <NUM> is shown. In <FIG>, a schematic diagram of the display unit <NUM> is shown. The humidity measuring device <NUM> measures a relative humidity of the gas and a temperature of the gas. Hereinafter, the relative humidity will be referred to simply as a humidity.

The casing <NUM> includes a main body portion <NUM> and a connecting portion <NUM>. The main body portion <NUM> includes an accommodating section <NUM> disposed in the interior of the main body portion <NUM>. The accommodating section <NUM> is a space formed inside the main body portion <NUM>. The main body portion <NUM> includes a supply tube <NUM> disposed in the interior of the main body portion <NUM>. The main body portion <NUM> includes a discharge tube <NUM> disposed in the interior of the main body portion <NUM>. The supply tube <NUM> is connected to the accommodating section <NUM>. The discharge tube <NUM> is connected to the accommodating section <NUM>. As shown in <FIG>, an opening of the discharge tube <NUM> in the accommodating section <NUM> is arranged at a position that is offset, with respect to an opening of the supply tube <NUM> in the accommodating section <NUM>, in a radial direction of the opening of the supply tube <NUM>. Gas is supplied from the supply tube <NUM> into the accommodating section <NUM>. The gas that is supplied into the accommodating section <NUM> is discharged from the discharge tube <NUM> into the atmosphere.

The humidity measuring device <NUM> includes an electronic circuit board <NUM>. The electronic circuit board <NUM> is arranged between the main body portion <NUM> and the display unit <NUM>. A temperature and humidity measurement unit <NUM> is mounted on the electronic circuit board <NUM>. The temperature and humidity measurement unit <NUM> is accommodated in the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> is an electronic component in which a temperature sensing element and a humidity sensing element are mounted in one single integrated circuit. The temperature sensing element measures the temperature of the gas in the accommodating section <NUM>. The humidity sensing element measures the humidity of the gas in the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> corresponds to a measurement unit of the present invention. The temperature and humidity measurement unit <NUM> outputs to the display unit <NUM> the temperature and humidity of the gas that were measured.

The connecting portion <NUM> is mounted on the main body portion <NUM>. The connecting portion <NUM> includes a connecting tube <NUM> in the interior of the connecting portion <NUM>. Gas is capable of flowing between the connecting tube <NUM> and the supply tube <NUM> of the main body portion <NUM>.

The connecting tube <NUM> includes an orifice <NUM>. A filter <NUM> is mounted in the connecting tube <NUM>. The filter <NUM> is made of metal. In the connecting tube <NUM>, the orifice <NUM> is arranged at a position in closer proximity to the main body portion <NUM> than the position where the filter <NUM> is mounted. More specifically, the orifice <NUM> is arranged at a position in closer proximity to the accommodating section <NUM> than the position where the filter <NUM> is mounted. In the orifice <NUM>, the cross-sectional area of a minimum diameter portion of the hole of the orifice <NUM> is smaller than the cross-sectional area of the discharge tube <NUM>. Therefore, a flow path resistance of a pathway (hereinafter, referred to as a discharge pathway) through which the gas from the accommodating section <NUM> is discharged is smaller than a flow path resistance of a pathway (hereinafter, referred to as a supply pathway) through which the gas is supplied to the accommodating section <NUM>. Consequently, the pressure of the gas inside the accommodating section <NUM> becomes the atmospheric pressure. The temperature and humidity measurement unit <NUM>, which is accommodated in the accommodating section <NUM>, measures the temperature of the gas under atmospheric pressure. The temperature and humidity measurement unit <NUM>, which is accommodated in the accommodating section <NUM>, also measures the humidity of the gas under atmospheric pressure.

<FIG> is a perspective view of the casing <NUM>. The connecting portion <NUM> is fixed to the main body portion <NUM> by connecting pins <NUM>. The user can pull out the connecting pins <NUM>. In a state in which the connecting pins <NUM> are pulled out from the main body portion <NUM> and the connecting portion <NUM>, the user is capable of detaching the connecting portion <NUM> from the main body portion <NUM>. The connecting portion <NUM> is detached from the main body portion <NUM> in a state in which the filter <NUM> is mounted in the connecting portion <NUM>. Consequently, the user is capable of easily replacing the filter <NUM> of the humidity measuring device <NUM>.

<FIG> is a view showing an example of installing the humidity measuring device <NUM>. The humidity measuring device <NUM> is installed in a tube <NUM>. A compressed gas flows in the interior of the tube <NUM>. The compressed gas is a gas in which the pressure of the gas is higher than atmospheric pressure. Hereinafter, even if the gas is a compressed gas, the gas may be simply referred to as a gas.

The temperature, the humidity, and the dew point temperature of the gas vary depending on the pressure of the gas. The temperature, the humidity, and the dew point temperature of a compressed gas in which the pressure of the gas is higher than atmospheric pressure may be described as a temperature under the pressure of the gas, a humidity under the pressure of the gas, and a dew point temperature under the pressure of the gas. The temperature, the humidity, and the dew point temperature of a gas in which the pressure of the gas is equivalent to the atmospheric pressure may be described as a temperature under atmospheric pressure of the gas, a humidity under atmospheric pressure of the gas, and a dew point temperature under atmospheric pressure of the gas.

The humidity measuring device <NUM> measures the humidity and the temperature of the gas that flows through the interior of the tube <NUM>. The connecting portion <NUM> of the humidity measuring device <NUM> is inserted into a non-illustrated insertion hole provided in the tube <NUM>. Due to this feature, a portion of the gas that flows into the interior of the tube <NUM> passes through the connecting tube <NUM> of the connecting portion <NUM>, and the supply tube <NUM> of the main body portion <NUM>, and is supplied to the accommodating section <NUM>. The gas that flows through the interior of the tube <NUM> is a gas that is dehumidified by a dehumidifying device <NUM>, which will be described next.

<FIG> is a view showing an example of installing the humidity measuring device <NUM>. The humidity measuring device <NUM> may be installed in the dehumidifying device <NUM>. The dehumidifying device <NUM> removes moisture in the gas that passes through the interior of the dehumidifying device <NUM>. The humidity measuring device <NUM> measures the humidity and the temperature of the compressed gas that is discharged from the dehumidifying device <NUM>.

As shown in <FIG>, the display unit <NUM> is fixed to the main body portion <NUM> of the casing <NUM>. <FIG> is a control block diagram of the humidity measuring device <NUM>. With reference to the control block diagram of <FIG>, a description will be given concerning the configuration of the display unit <NUM>.

The display unit <NUM> includes a dew point temperature calculation unit <NUM>, a set value storage unit <NUM>, a first output unit <NUM>, a second output unit <NUM>, a display control unit <NUM>, and a display device <NUM>.

The dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> outputs the calculated dew point temperature to the first output unit <NUM>, the second output unit <NUM>, and the display control unit <NUM>.

Hereinafter, the "temperature of the gas measured by the temperature and humidity measurement unit <NUM>" may be referred to as a "measured temperature". The "humidity of the gas measured by the temperature and humidity measurement unit <NUM>" may be referred to as a "measured humidity". The "dew point temperature of the gas calculated by the dew point temperature calculation unit <NUM>" may be referred to as a "calculated dew point temperature".

The set value storage unit <NUM> stores a set temperature, a set humidity, and a set dew point temperature. The set temperature, the set humidity, and the set dew point temperature are input to the first output unit <NUM>, as will be described later. The set temperature, the set humidity, and the set dew point temperature may be values set by the user of the humidity measuring device <NUM>. The set temperature, the set humidity, and the set dew point temperature may also be values set by a manufacturer of the humidity measuring device <NUM> at a time of shipment of the humidity measuring device <NUM>.

The first output unit <NUM> compares the set temperature with the measured temperature. The first output unit <NUM> outputs a comparison result (hereinafter, such a result may be referred to as a temperature comparison result) to an external device <NUM>. The temperature comparison result may be information numerically indicating a difference between the set temperature and the measured temperature. The temperature comparison result may be information indicating a highness or lowness of the measured temperature with respect to the set temperature.

The first output unit <NUM> compares the set humidity with the measured humidity. The first output unit <NUM> outputs a comparison result (hereinafter, such a result may be referred to as a humidity comparison result) to the external device <NUM>. The humidity comparison result may be information numerically indicating a difference between the set humidity and the measured humidity. The humidity comparison result may be information indicating a highness or lowness of the measured humidity with respect to the set humidity.

The first output unit <NUM> compares the set dew point temperature with the calculated dew point temperature. The first output unit <NUM> outputs a comparison result (hereinafter, such a result may be referred to as a dew point temperature comparison result) to the external device <NUM>. The dew point temperature comparison result may be information numerically indicating a difference between the set dew point temperature and the calculated dew point temperature. The dew point temperature comparison result may be information numerically indicating a highness or lowness of the calculated dew point temperature with respect to the set dew point temperature.

The second output unit <NUM> outputs the measured temperature to an external device <NUM>. The second output unit <NUM> outputs the measured humidity to the external device <NUM>. The second output unit <NUM> outputs the calculated dew point temperature to the external device <NUM>. The external device <NUM> may be the same device as the external device <NUM>. The external device <NUM> may also be a device that is different from the external device <NUM>.

The display control unit <NUM> controls the display device <NUM> to thereby cause information concerning the measured temperature to be displayed on the display device <NUM>. The display control unit <NUM> controls the display device <NUM> to thereby cause information concerning the measured humidity to be displayed on the display device <NUM>. The display control unit <NUM> controls the display device <NUM> to thereby cause information concerning the calculated dew point temperature to be displayed on the display device <NUM>. The display control unit <NUM> may control the display device <NUM> to thereby cause at least one of the information concerning the measured temperature, the information concerning the measured humidity, or the information concerning the calculated dew point temperature to be displayed on the display device <NUM>. The units of the measured temperature, the calculated dew point temperature, the set temperature, and the set dew point temperature are in units of "°C".

<FIG> is a view showing an exemplary display of the display device <NUM>. The display device <NUM> includes a humidity display region <NUM>. The measured humidity is displayed numerically in the humidity display region <NUM>. The display device <NUM> includes a dew point temperature display region <NUM>. The calculated dew point temperature is displayed numerically in the dew point temperature display region <NUM>. The display device <NUM> includes a temperature display region <NUM>. The measured temperature is displayed numerically in the temperature display region <NUM>.

<FIG> are views showing exemplary displays of the display device <NUM>. The exemplary displays of the display device <NUM> shown in <FIG> are exemplary displays that differ from the exemplary display of the display device <NUM> shown in <FIG>. The display device <NUM> includes a humidity display region <NUM>. The measured humidity is displayed numerically in the humidity display region <NUM>. The display device <NUM> includes a dew point temperature display region <NUM>. The two slashes "//" shown near the center of the dew point temperature display region <NUM> shown in <FIG> indicate a position where the calculated dew point temperature is <NUM>. In the case that the calculated dew point temperature is negative, then as shown in <FIG>, bars (g-segments) "-" are displayed only on the right side of the slashes "//". In the case that the calculated dew point temperature is positive, then as shown in <FIG>, bars (g-segments) "-" are displayed such that they extend to the left side of the slashes "//". In the dew point temperature display region <NUM>, the more that the bars (g-segments) "-" extend into the left side, the higher the calculated dew point temperature that is displayed by the display device <NUM> is.

<FIG> are views showing exemplary displays of the display device <NUM>. The exemplary displays of the display device <NUM> shown in <FIG> are exemplary displays that differ from the exemplary displays of the display device <NUM> shown in <FIG> and <FIG>. The display device <NUM> includes a humidity display region <NUM>. The measured humidity is displayed numerically in the humidity display region <NUM>. The display device <NUM> includes a temperature display region <NUM>. The measured temperature is displayed numerically in the temperature display region <NUM>. The display device <NUM> indicates the calculated dew point temperature by a color of the numbers displayed in the humidity display region <NUM>. In the case that the calculated dew point temperature is negative, the display device <NUM> displays the numbers in the humidity display region <NUM> in blue. In the case that the calculated dew point temperature is positive, the display device <NUM> displays the numbers in the humidity display region <NUM> in red. The colors of the numbers displayed in the humidity display region <NUM> described above are given by way of example, and the information concerning the calculated dew point temperature may be displayed in different colors.

Within the display unit <NUM>, the respective constituent features thereof except for the display device <NUM> are realized by a non-illustrated microcontroller. By a non-illustrated computation processing device provided in the microcontroller executing programs stored in a non-illustrated memory provided on the microcontroller, the functions of the dew point temperature calculation unit <NUM>, the first output unit <NUM>, the second output unit <NUM>, and the display control unit <NUM> are realized. Further, the set value storage unit <NUM> is realized by securing a storage region in which respective set values are stored in a portion of the memory.

Moreover, within the display unit <NUM>, the respective constituent features thereof excluding the display device <NUM> may be configured by integrated circuits such as a non-illustrated FPGA (Field Programmable Gate Array), an ASIC (application specific integrated circuit), or the like.

According to <FIG>, the opening of the discharge tube <NUM> in the accommodating section <NUM> is arranged at a position that is offset with respect to an opening of the supply tube <NUM> in the accommodating section <NUM>. Consequently, the gas that has flowed into the accommodating section <NUM> from the supply tube <NUM> is diffused or spread out inside the accommodating section <NUM>, and thereafter, is discharged from the discharge tube <NUM>.

Using a computer, the present inventors have carried out simulations concerning the distribution of the humidity of the gas in the interior of the accommodating section <NUM>. <FIG> are diagrams showing simulation results. <FIG> shows a simulation result in a Comparative Example <NUM>. In Comparative Example <NUM>, the direction in which the gas flows in from the supply tube <NUM> into the accommodating section <NUM>, and the direction in which the gas flows out from the accommodating section <NUM> into the discharge tube <NUM> are positioned mutually on a straight line with each other. <FIG> shows a simulation result in a Comparative Example <NUM>. In Comparative Example <NUM>, an opening of the discharge tube <NUM> in the accommodating section <NUM> is arranged at a position that is offset, with respect to the opening of the supply tube <NUM> in the accommodating section <NUM>, in a radial direction of the opening of the supply tube <NUM>. Owing to this feature, in Comparative Example <NUM>, the direction in which the gas flows from the supply tube <NUM> into the accommodating section <NUM>, and the direction in which the gas flows out from the accommodating section <NUM> into the discharge tube <NUM> are positioned mutually on different straight lines.

In the simulations of Comparative Example <NUM> and Comparative Example <NUM>, the diameter of the hole of the orifice <NUM> was set to <NUM>. In the simulations of Comparative Example <NUM> and Comparative Example <NUM>, the humidity of the gas that flows into the accommodating section <NUM> was set to <NUM>%. In the simulations of Comparative Example <NUM> and Comparative Example <NUM>, the flow rate of the gas that flows into the accommodating section <NUM> was set to <NUM>/min.

In Comparative Example <NUM>, the gas that has flowed into the accommodating section <NUM> from the supply tube <NUM> is discharged from the discharge tube <NUM> without being diffused or spread out inside the accommodating section <NUM>. Therefore, in the simulation in Comparative Example <NUM>, as shown in <FIG>, the distribution of the humidity of the gas in the accommodating section <NUM> is not uniform. On the other hand, in Comparative Example <NUM>, the gas that has flowed into the accommodating section <NUM> from the supply tube <NUM> impinges against the side surface of the accommodating section <NUM>, and after being diffused or spread out inside the accommodating section <NUM>, is discharged from the discharge tube <NUM>. Therefore, in the simulation in Comparative Example <NUM>, as shown in <FIG>, the distribution of the humidity of the gas in the accommodating section <NUM> is substantially uniform.

From these simulation results, it was shown that the gas that flows into the accommodating section <NUM> was diffused or spread out more widely in Comparative Example <NUM> than in Comparative Example <NUM>.

The present inventors conducted experiments concerning the accuracy in measuring the humidity of the gas by the temperature and humidity measurement unit <NUM>. <FIG> are diagrams showing experimental environments in which experiments were conducted by the present inventors. <FIG> shows the experimental environment in a Comparative Example <NUM>. In Comparative Example <NUM>, the direction in which the gas flows in from the supply tube <NUM> into the accommodating section <NUM>, and the direction in which the gas flows out from the accommodating section <NUM> into the discharge tube <NUM> are positioned mutually on a straight line with each other. <FIG> shows the experimental environment in a Comparative Example <NUM>. In Comparative Example <NUM>, an opening of the discharge tube <NUM> in the accommodating section <NUM> is arranged at a position that is offset, with respect to the opening of the supply tube <NUM> in the accommodating section <NUM>, in a radial direction of the opening of the supply tube <NUM>. Owing to this feature, in Comparative Example <NUM>, the direction in which the gas flows from the supply tube <NUM> into the accommodating section <NUM>, and the direction in which the gas flows out from the accommodating section <NUM> into the discharge tube <NUM> are positioned mutually on different straight lines. In these experiments, a dry gas (with a humidity of <NUM>%) was allowed to flow into the accommodating section <NUM> which is in a normal humidity state (a humidity of <NUM>%).

In the experimental environment in Comparative Example <NUM> shown in <FIG>, the humidity measured by the temperature and humidity measurement unit <NUM> was <NUM>%. A measurement error of the humidity (<NUM>%) that was measured by the temperature and humidity measurement unit <NUM> with respect to the humidity (<NUM>%) of the gas that was made to flow into the accommodating section <NUM> was +<NUM>%. In the experimental environment in Comparative Example <NUM> shown in <FIG>, the humidity measured by the temperature and humidity measurement unit <NUM> was <NUM>%. A measurement error of the humidity (<NUM>%) that was measured by the temperature and humidity measurement unit <NUM> with respect to the humidity (<NUM>%) of the gas that was made to flow into the accommodating section <NUM> was +<NUM>%.

From these experimental results, it was shown that the accuracy in measuring the humidity of the gas by the temperature and humidity measurement unit <NUM> is more improved in Comparative Example <NUM> than in Comparative Example <NUM>.

In the humidity measuring device <NUM> because the connecting tube <NUM> includes the orifice <NUM>, the flow path resistance of the gas discharge pathway of the accommodating section <NUM> is smaller than the flow path resistance of the gas supply pathway of the accommodating section <NUM>. Consequently, the pressure of the gas inside the accommodating section <NUM> becomes the atmospheric pressure. Instead of the orifice <NUM>, a structure may be considered in which the connecting tube <NUM> includes a pressure reducing valve. The pressure reducing valve, by releasing a portion of the gas that passes through the connecting tube <NUM> into the atmosphere, is capable of adjusting the pressure of the gas supplied to the accommodating section <NUM> to be equivalent to the atmospheric pressure. The structure of the orifice <NUM> is simpler in comparison with that of the pressure reducing valve. In the humidity measuring device <NUM> according to the present embodiment, since the connecting tube <NUM> includes the orifice <NUM> instead of a pressure reducing valve, the structure of the humidity measuring device <NUM> can be simplified.

The filter <NUM> that is mounted in the connecting tube <NUM> acts as a resistance to the gas that passes through the filter <NUM>. Therefore, it may be considered that the filter <NUM> increases the flow path resistance of the supply pathway. Normally, the filter <NUM> is designed in a manner so that, while the filter <NUM> removes foreign material in the gas that passes through the filter <NUM>, the resistance with respect to the gas that passes through the filter <NUM> is as small as possible. In order to generate a flow path resistance that is equivalent to the flow path resistance due to the orifice <NUM> in the filter <NUM>, it is necessary to mount the filter <NUM> in the connecting tube <NUM>, which is considerably longer in comparison to the axial length of the hole of the orifice <NUM>. In the humidity measuring device <NUM> according to the present embodiment, because the orifice <NUM> increases the flow path resistance of the supply path, the humidity measuring device <NUM> can be made smaller in scale.

Compared to a case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, the flow velocity of the gas that flows into the accommodating section <NUM> becomes higher. As the flow velocity of the gas that flows into the accommodating section <NUM> becomes higher, the gas is diffused or spread out over a wider range when the gas collides against the side surface of the accommodating section <NUM>. As the flow velocity of the gas that flows into the accommodating section <NUM> becomes higher, the time until the gas that flows into the accommodating section <NUM> and thereafter collides against the side surface of the accommodating section <NUM> becomes shortened, and the gas is diffused or spread out more rapidly.

Therefore, compared to a case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, the gas that has flowed into the accommodating section <NUM> is diffused or spread out more rapidly and over a wider range inside the accommodating section <NUM>. As a result, compared to the case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, with respect to changes in the temperature and humidity or the like of the target gas to be measured, the response speed of the measurement result of the target gas to be measured by the temperature and humidity measurement unit <NUM> is improved.

Using a computer, the present inventors have carried out simulations concerning the flow rate of the gas that flows into the accommodating section <NUM>. <FIG> are diagrams showing simulation results. <FIG> is a simulation result in the case that the filter <NUM> causes the flow path resistance of the supply pathway to increase. <FIG> is a simulation result in the case that the orifice <NUM> causes the flow path resistance of the supply pathway to increase.

In these simulations, an inner diameter of the supply tube <NUM> was set to <NUM>. In these simulations, the inner diameter of the tube in a portion where the filter <NUM> is provided was set to <NUM>, and an outer diameter of the filter <NUM> was also set to <NUM>. In these simulations, the length of the filter <NUM> was set to <NUM>. In these simulations, an inner diameter of the hole of the orifice <NUM> was set to <NUM> mm. In these simulations, an axial length of the hole of the orifice <NUM> was set to <NUM> mm. In these simulations, the humidity of the gas that flows into the accommodating section <NUM> was set to <NUM>%. In these simulations, the flow rate of the gas that flows into the accommodating section <NUM> was set to <NUM>/min.

In the case that the filter <NUM> causes the flow path resistance of the supply pathway to increase, then as shown in <FIG>, the flow rate of the gas that passes through the filter <NUM> is high, but the flow rate of the gas after having passed through the filter <NUM> is low. The reason why the flow velocity of the gas after having passed through the filter <NUM> decreases in this manner, notwithstanding the fact that the flow velocity of the gas while passing through the filter <NUM> is high, is as follows.

At an inlet portion where the gas flows into the filter <NUM>, since the gas flows into the filter <NUM> (having an outer diameter of <NUM>) from the supply tube <NUM> (having an inner diameter <NUM>), the flow velocity of the gas becomes higher. In the interior of the filter <NUM>, as the flow velocity of the gas becomes higher, the flow path resistance of the filter <NUM> with respect to the gas increases. Therefore, while passing through the filter <NUM>, the gas diffuses (spreads out) from a location in the interior of the filter <NUM> where the flow path resistance is high to a location where the flow path resistance is low. Owing to this feature, at an outlet portion where the gas flows out from the filter <NUM>, regardless of the aforementioned flow velocity of the gas at the inlet portion, the flow velocity of the gas becomes substantially constant. Due to the flow path resistance of the filter <NUM> with respect to the gas, in comparison with the pressure of the gas before having passed through the filter <NUM>, the pressure of the gas after having passed through the filter <NUM> is lower. However, while passing through the filter <NUM>, because the gas diffuses (spreads out) in the interior of the filter <NUM>, the flow velocity of the gas is suppressed to a speed that is dependent on the external shape of the filter <NUM>. At the aforementioned outlet portion, because the gas flows in from the filter <NUM> (having an outer diameter of <NUM>) to the supply tube <NUM> (having an inner diameter of <NUM>), the flow velocity of the gas is further reduced.

On the other hand, in the case that the orifice <NUM> causes the flow path resistance of the supply pathway to increase, then as shown in <FIG>, the flow velocity of the gas after having passed through the orifice <NUM> remains in a high state. The reason why the flow velocity of the gas after having passed through the orifice <NUM> is maintained in such a state is as follows.

At an inlet portion where the gas flows into the orifice <NUM>, since the gas flows into the hole of the orifice <NUM> (having an inner diameter of <NUM>) from the supply tube <NUM> (having an inner diameter <NUM>), the flow velocity of the gas becomes higher. Due to the flow path resistance of the orifice <NUM> with respect to the gas, in comparison with the pressure of the gas before having passed through the orifice <NUM>, the pressure of the gas after having passed through the orifice <NUM> is lower. The axial length of the hole of the orifice <NUM> is <NUM>, and the flow velocity of the gas significantly increases while passing through the hole of the orifice <NUM>. On the other hand, at the outlet portion where the gas flows out from the orifice <NUM>, because the gas flows into the supply tube <NUM> (having an inner diameter of <NUM>) from the hole of the orifice <NUM> (having an inner diameter of <NUM>), the flow velocity of the gas decreases. However, while the gas is passing through the orifice <NUM>, since the flow velocity of the gas is sufficiently increased, the flow velocity of the gas can be maintained in a high state even inside the supply tube <NUM>.

Based on the results of these simulations, compared to a case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, it was shown that the flow velocity of the gas that flows into the accommodating section <NUM> is higher.

Using a computer, the present inventors have carried out simulations concerning the distribution of the humidity of the gas inside the accommodating section <NUM>. <FIG> are diagrams showing simulation results. <FIG> shows a simulation result in the case that the filter <NUM> causes the flow path resistance of the supply pathway to increase. <FIG> shows a simulation result in the case that the orifice <NUM> causes the flow path resistance of the supply pathway to increase.

In these simulations, the outer diameter of the filter <NUM> was set to <NUM>. In these simulations, the length of the filter <NUM> was set to <NUM>. In these simulations, the diameter of the hole of the orifice <NUM> was set to <NUM>. In these simulations, the length of the hole of the orifice <NUM> was set to <NUM>. In these simulations, the humidity of the gas that flows into the accommodating section <NUM> was set to <NUM>%. In these simulations, the flow rate of the gas that flows into the accommodating section <NUM> was set to <NUM>/min.

In the case that the filter <NUM> causes the flow path resistance of the supply pathway to increase, then as shown in <FIG>, the distribution of the humidity of the gas in the accommodating section <NUM> is not uniform. On the other hand, in the case that the orifice <NUM> causes the flow path resistance of the supply pathway to increase, then as shown in <FIG>, the distribution of the humidity of the gas in the accommodating section <NUM> becomes substantially uniform.

As shown in the simulation results of <FIG>, compared to a case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, the flow velocity of the gas that flows into the accommodating section <NUM> is higher. As the flow velocity of the gas that flows into the accommodating section <NUM> becomes higher, the gas is diffused or spread out over a wider range when the gas collides against the side surface of the accommodating section <NUM>.

According to the simulation results of <FIG>, compared to a case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, it was shown that the gas that has flowed into the accommodating section <NUM> became more diffused inside the accommodating section <NUM>.

The present inventors conducted experiments concerning the response speed in measuring the humidity by the temperature and humidity measurement unit <NUM>, with respect to changes in the humidity of the target gas to be measured. In such experiments, by the temperature and humidity measurement unit <NUM>, the present inventors measured the humidity of the gas after having passed through the orifice <NUM>, and the humidity of the gas after having passed through the filter <NUM>. In such experiments, the diameter of the hole of the orifice <NUM> was set to <NUM>. In such experiments, the outer diameter of the filter <NUM> was set to <NUM>.

In a first experiment (hereinafter referred to as Experiment <NUM>), prior to starting of the experiment, the accommodating section <NUM> was filled with a gas having a humidity of <NUM>%. The gas having a humidity of <NUM>% was supplied to the accommodating section <NUM> over a period of <NUM> seconds after having started the experiment. After passage of <NUM> seconds from having started the experiment, supply of a gas having a humidity of <NUM>% into the accommodating section <NUM> was initiated. In a second experiment (hereinafter referred to as Experiment <NUM>), prior to starting of the experiment, the accommodating section <NUM> was filled with a gas having a humidity of <NUM>%. The gas having a humidity of <NUM>% was supplied to the accommodating section <NUM> over a period of <NUM> seconds after having started the experiment. After passage of <NUM> seconds from having started the experiment, supply of a gas having a humidity of <NUM>% into the accommodating section <NUM> was initiated.

<FIG> show experimental results. <FIG> shows the experimental results of Experiment <NUM> in which the humidity of the gas supplied to the accommodating section <NUM> was made to change so as to become higher from <NUM>% to <NUM>%. <FIG> shows the experimental results of Experiment <NUM> in which the humidity of the gas supplied to the accommodating section <NUM> was made to change so as to become lower from <NUM>% to <NUM>%. In Experiment <NUM>, the measured humidity of the gas after having passed through the orifice <NUM> rises more rapidly than the measured humidity of the gas after having passed through the filter <NUM>. In Experiment <NUM>, the measured humidity of the gas after having passed through the orifice <NUM> decreases more rapidly than the measured humidity of the gas after having passed through the filter <NUM>.

From these experimental results, compared to the case in which the filter <NUM> causes the flow path resistance of the supply pathway to increase, in the case of the orifice <NUM> causing the flow path resistance of the supply pathway to increase, it was shown that the response speed in measuring the humidity of the target gas to be measured by the temperature and humidity measurement unit <NUM> is improved, with respect to changes in the humidity of the target gas to be measured.

In the humidity measuring device <NUM> the display unit <NUM> is fixed to the casing <NUM>. The display unit <NUM> includes the display device <NUM>. The display device <NUM> displays the humidity of the gas, the temperature of the gas, and the dew point temperature of the gas. Consequently, the user is capable of confirming the humidity of the gas, the temperature of the gas, and the dew point temperature of the gas, at the location where the humidity measuring device <NUM> is installed.

In the humidity measuring device <NUM> the first output unit <NUM> outputs to the external device <NUM> the comparison result between the set humidity and the humidity (the measured humidity) of the gas measured by the temperature and humidity measurement unit <NUM>. Consequently, the humidity measuring device <NUM> is capable of outputting to the external device <NUM> the comparison result between the set humidity and the measured humidity.

In the humidity measuring device <NUM> the first output unit <NUM> outputs to the external device <NUM> the comparison result between the set dew point temperature and the dew point temperature (the calculated dew point temperature) of the gas calculated by the dew point temperature calculation unit <NUM>. Consequently, the humidity measuring device <NUM> according is capable of outputting to the external device <NUM> the comparison result between the set dew point temperature and the calculated dew point temperature.

In the humidity measuring device <NUM> the second output unit <NUM> outputs to the external device <NUM> the humidity (the measured humidity) of the gas measured by the temperature and humidity measurement unit <NUM>. Consequently, the humidity measuring device <NUM> is capable of outputting the measured humidity to the external device <NUM>.

In the humidity measuring device <NUM> the second output unit <NUM> outputs to the external device <NUM> the dew point temperature (the calculated dew point temperature) of the gas calculated by the dew point temperature calculation unit <NUM>. Consequently, the humidity measuring device <NUM> is capable of outputting the calculated dew point temperature to the external device <NUM>.

In the humidity measuring device <NUM> the direction in which the gas flows from the supply tube <NUM> into the accommodating section <NUM>, and the direction in which the gas flows out from the accommodating section <NUM> into the discharge tube <NUM> are positioned mutually on different straight lines. In accordance with this feature, the temperature and humidity measurement unit <NUM> is capable of improving the accuracy in measuring the humidity of the gas.

In the humidity measuring device <NUM> the connecting tube <NUM> includes the orifice <NUM>. The cross-sectional area of the hole of the orifice <NUM> is smaller than the cross-sectional area of the discharge tube <NUM>. Consequently, the flow path resistance of the gas supply pathway becomes larger than the flow path resistance of the gas discharge pathway. Therefore, the pressure of the gas inside the accommodating section <NUM> can be set to the atmospheric pressure. The dew point temperature calculation unit <NUM> can calculate the dew point temperature under atmospheric pressure of the gas, based on the temperature of the gas and the humidity of the gas measured by the temperature and humidity measurement unit <NUM>.

In the humidity measuring device <NUM> the filter <NUM> is mounted in the connecting tube <NUM>. Further, the orifice <NUM> is arranged in closer proximity to the side of the accommodating section <NUM> than the filter <NUM>. Owing to these features, it is possible to prevent foreign material from clogging the hole of the orifice <NUM> of the connection tube <NUM>.

In the humidity measuring device <NUM> the filter <NUM> is made of metal. Consequently, it is possible to prevent moisture in the gas from being absorbed by the filter <NUM>. Therefore, the humidity measuring device <NUM> is capable of improving the accuracy in measuring the humidity of the gas.

In the humidity measuring device <NUM> the user is capable of removing the connecting portion <NUM> from the main body portion <NUM> in a state in which the filter <NUM> is mounted in the connecting portion <NUM>. Thus, the user is capable of easily replacing the filter <NUM> of the humidity measuring device <NUM>.

<FIG> shows the humidity measuring device <NUM>. In <FIG>, a cross-sectional view of a casing <NUM> is shown. In <FIG>, a schematic diagram of the display unit <NUM> is shown.

In the humidity measuring device <NUM> of <FIG>, the connecting tube <NUM> that is formed in the interior of the connecting portion <NUM> includes the orifice <NUM> (see <FIG>). In contrast thereto, in the humidity measuring device <NUM> of <FIG>, the connecting tube <NUM> that is formed in the interior of the connecting portion <NUM> does not include the orifice (see <FIG>). In the humidity measuring device <NUM> according to the present embodiment, the discharge tube <NUM> that is formed in the interior of the main body portion <NUM> of the casing <NUM> includes an orifice <NUM>. In the orifice <NUM>, the cross-sectional area of a minimum diameter portion of the hole of the orifice <NUM> is smaller than the cross-sectional area of the supply tube <NUM>. In the orifice <NUM>, the cross-sectional area of the minimum diameter portion of the hole of the orifice <NUM> is also smaller than the cross-sectional area of the connecting tube <NUM>. Other constituent features of the humidity measuring device <NUM> of <FIG> are the same as the constituent features of the humidity measuring device <NUM> of <FIG>.

Since the connecting tube <NUM> does not include an orifice, and the discharge tube <NUM> includes the orifice <NUM>, the pressure of the gas inside the accommodating section <NUM> becomes substantially the same as the pressure of the compressed gas inside the tube <NUM>, or alternatively, the pressure of the compressed gas that is discharged by the dehumidifying device <NUM>. The temperature and humidity measurement unit <NUM> measures the temperature under the pressure of the gas. The temperature and humidity measurement unit <NUM> measures the humidity under the pressure of the gas. The dew point temperature calculation unit <NUM> of the display unit <NUM> calculates the dew point temperature under the pressure of the gas, based on the temperature under the pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under the pressure of the gas measured by the temperature and humidity measurement unit <NUM>.

In the humidity measuring device <NUM> of <FIG>, the discharge tube <NUM> includes the orifice <NUM>. The cross-sectional area of the hole of the orifice <NUM> is smaller than the cross-sectional area of the supply tube <NUM>. In the orifice <NUM>, the cross-sectional area of the hole of the orifice <NUM> is smaller than the cross-sectional area of the connecting tube <NUM>. Since the connecting tube <NUM> does not include an orifice, and the discharge tube <NUM> includes the orifice <NUM>, the pressure of the gas inside the accommodating section <NUM> becomes substantially the same as the pressure of the compressed gas inside the tube <NUM>, or alternatively, the pressure of the compressed gas that is discharged by the dehumidifying device <NUM>. The temperature and humidity measurement unit <NUM> is capable of measuring the temperature under the pressure of the gas. The temperature and humidity measurement unit <NUM> is capable of measuring the humidity under the pressure of the gas. The dew point temperature calculation unit <NUM> is capable of calculating the dew point temperature under the pressure of the gas, based on the temperature under the pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under the pressure of the gas measured by the temperature and humidity measurement unit <NUM>.

<FIG> is a control block diagram of the humidity measuring device <NUM>. With reference to the control block diagram of <FIG>, a description will be given concerning the configuration of the display unit <NUM>.

The display unit <NUM> of the humidity measuring device <NUM> of <FIG> includes the dew point temperature calculation unit <NUM>, the first output unit <NUM>, the display control unit <NUM>, the display device <NUM>, and a communication unit <NUM>. The dew point temperature calculation unit <NUM>, the display control unit <NUM>, and the display device <NUM> are the same as the dew point temperature calculation unit <NUM>, the display control unit <NUM>, and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> <FIG>.

The communication unit <NUM> carries out communications with the external device <NUM>. The communication unit <NUM> receives the set temperature, the set humidity, and the set dew point temperature from the external device <NUM>. The communication unit <NUM> outputs to the first output unit <NUM> the set temperature, the set humidity, and the set dew point temperature received by the communication unit <NUM>. The set temperature, the set humidity, and the set dew point temperature may be values set by the user of the external device <NUM>. The set temperature, the set humidity, and the set dew point temperature may also be values set by a manufacturer of the external device <NUM> at a time of shipment of the humidity measuring device <NUM>.

The first output unit <NUM> outputs to the communication unit <NUM> a comparison result between the set temperature and the measured temperature. The first output unit <NUM> outputs to the communication unit <NUM> a comparison result between the set humidity and the measured humidity. The first output unit <NUM> outputs to the communication unit <NUM> the comparison result between the set dew point temperature and the calculated dew point temperature.

The communication unit <NUM> transmits to the external device <NUM> the comparison result between the set temperature and the measured temperature. The communication unit <NUM> transmits to the external device <NUM> the comparison result between the set humidity and the measured humidity. The communication unit <NUM> transmits to the external device <NUM> the comparison result between the set dew point temperature and the calculated dew point temperature.

In the humidity measuring device <NUM> of <FIG>, the display unit <NUM> includes the communication unit <NUM>. The communication unit <NUM> carries out communications with the external device <NUM>. The communication unit <NUM> is capable of receiving the respective set values which are set on the side of the external device <NUM>. In accordance with these features, in the humidity measuring device <NUM> of <FIG>, the first output unit <NUM> is capable of comparing the respective set values that are set in the external device <NUM> with each of the measured temperature, the measured humidity, and the calculated dew point temperature. In the humidity measuring device <NUM> the communication unit <NUM> is capable of transmitting to the external device <NUM> the comparison results compared by the first output unit <NUM>.

<FIG> shows the humidity measuring device <NUM>. The humidity measuring device <NUM> includes a casing <NUM> and the display unit <NUM>. In <FIG>, a cross-sectional view of the casing <NUM> is shown. In <FIG>, a schematic diagram of the display unit <NUM> is shown.

The casing <NUM> includes an accommodating section <NUM> in the interior of the casing <NUM>. The casing <NUM> includes a supply tube <NUM> in the interior of the casing <NUM>. The casing <NUM> includes a discharge tube <NUM> in the interior of the casing <NUM>. The supply tube <NUM> is connected to the accommodating section <NUM>. The discharge tube <NUM> is connected to the accommodating section <NUM>. The gas, which is a target gas to be measured by the humidity measuring device <NUM>, is supplied from the supply tube <NUM> to the accommodating section <NUM>. The gas that is supplied into the accommodating section <NUM> is discharged from the discharge tube <NUM> into the atmosphere. An opening of the discharge tube <NUM> in the accommodating section <NUM> is arranged at a position that is offset, with respect to the opening of the supply tube <NUM> in the accommodating section <NUM>, in a radial direction of the opening of the supply tube <NUM>.

The humidity measuring device <NUM> includes an electronic circuit board <NUM>. The electronic circuit board <NUM> is arranged between the casing <NUM> and the display unit <NUM>. The temperature and humidity measurement unit <NUM> is mounted on the electronic circuit board <NUM>. The temperature and humidity measurement unit <NUM> is accommodated in the accommodating section <NUM>.

The supply tube <NUM> includes an orifice <NUM>. A filter <NUM> is mounted in the supply tube <NUM>. The filter <NUM> is made of metal. The orifice <NUM> is arranged at a position in closer proximity to the accommodating section <NUM> than the position where the filter <NUM> is mounted. In the orifice <NUM>, the cross-sectional area of a minimum diameter portion of the hole of the orifice <NUM> is smaller than the cross-sectional area of the discharge tube <NUM>. Therefore, a flow path resistance of a pathway (hereinafter, referred to as a discharge pathway) through which the gas from the accommodating section <NUM> is discharged is smaller than a flow path resistance of a pathway (hereinafter, referred to as a supply pathway) through which the gas is supplied to the accommodating section <NUM>. Consequently, the pressure of the gas inside the accommodating section <NUM> becomes the atmospheric pressure. The temperature and humidity measurement unit <NUM> measures the temperature of the gas inside the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> measures the humidity of the gas inside the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> outputs to the display unit <NUM> the temperature and humidity of the gas that were measured.

The casing <NUM> includes a branching tube <NUM> in the interior of the casing <NUM>. The branching tube <NUM> is connected to the supply tube <NUM>. A connected position of the branching tube <NUM> in the supply tube <NUM> is between the orifice <NUM> of the supply tube <NUM> and the filter <NUM>. A pressure measurement unit <NUM> is mounted on the electronic circuit board <NUM>. The branching tube <NUM> supplies the gas prior to passing through the orifice <NUM> to the pressure measurement unit <NUM>. The pressure measurement unit <NUM> measures the pressure of the supplied gas. In the case that the humidity measuring device <NUM> is installed in the tube <NUM>, the pressure of the gas supplied to the pressure measurement unit <NUM> is substantially the same as the pressure of the compressed gas that flows through the tube <NUM>. In the case that the humidity measuring device <NUM> is installed in the dehumidifying device <NUM>, the pressure of the gas supplied to the pressure measurement unit <NUM> is substantially the same as the pressure of the compressed gas discharged from the dehumidifying device <NUM>. Consequently, the pressure measurement unit <NUM> is capable of measuring the pressure of the gas at the measurement location.

The display unit <NUM> of the humidity measuring device <NUM> of <FIG> includes the dew point temperature calculation unit <NUM>, the display control unit <NUM>, and the display device <NUM>. The display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> of <FIG> and <FIG> are the same as the display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> of <FIG>.

The temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The pressure of the gas measured by the pressure measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. In the case that the humidity measuring device <NUM> is installed in the tube <NUM>, the pressure measurement unit <NUM> measures the pressure of the compressed gas that flows through the interior of the tube <NUM>. In the case that the humidity measuring device <NUM> is installed in the dehumidifying device <NUM>, the pressure measurement unit <NUM> measures the pressure of the compressed gas discharged from the dehumidifying device <NUM>. The dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas measured by the pressure measurement unit <NUM>, and thereby calculates the dew point temperature under the pressure of the gas.

Even if an absolute humidity of the gas (an amount of moisture contained in the gas) is the same, as the pressure of the gas becomes higher, the higher the dew point temperature becomes. Therefore, as the pressure of the gas in contact with the temperature and humidity measurement unit <NUM> is higher, it becomes easier for water droplets to become adhered to the temperature and humidity measurement unit <NUM>. In the case that water droplets adhere in this manner to the temperature and humidity measurement unit <NUM>, a concern arises in that the humidity measured by the temperature and humidity measurement unit <NUM> may become an abnormal value.

The humidity measuring device <NUM> of <FIG> and <FIG> includes the pressure measurement unit <NUM> that measures the pressure of the gas at the measurement position where the humidity measuring device <NUM> measures the humidity and the like of the gas. The dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, which is calculated based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas measured by the pressure measurement unit <NUM>, and thereby calculates the dew point temperature under the pressure of the gas. Consequently, since the temperature and humidity measurement unit <NUM> does not come into contact with the high pressure gas, the adherence of water droplets to the temperature and humidity measurement unit <NUM> is suppressed.

The display unit <NUM> of the humidity measuring device <NUM> of <FIG> includes the dew point temperature calculation unit <NUM>, the display control unit <NUM>, and the display device <NUM>. The display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> according to the present embodiment are the same as the display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> of <FIG>.

The temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The pressure of the gas, which is measured by a pressure measurement unit <NUM>, is input to the dew point temperature calculation unit <NUM>.

The pressure measurement unit <NUM> is disposed externally of the humidity measuring device <NUM>. In the case that the humidity measuring device <NUM> is installed in the tube <NUM>, the pressure measurement unit <NUM> measures the pressure of the compressed gas that flows through the interior of the tube <NUM>. In the case that the humidity measuring device <NUM> is installed in the dehumidifying device <NUM>, the pressure measurement unit <NUM> measures the pressure of the compressed gas discharged from the dehumidifying device <NUM>.

The dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas measured by the pressure measurement unit <NUM>, and thereby calculates the dew point temperature under the pressure of the gas.

In the humidity measuring device <NUM> of <FIG>, the dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas measured by the pressure measurement unit <NUM> that is disposed externally of the humidity measuring device <NUM>, and thereby calculates the dew point temperature under the pressure of the gas. Consequently, since the temperature and humidity measurement unit <NUM> does not come into contact with the high pressure gas, the adherence of water droplets to the temperature and humidity measurement unit <NUM> is suppressed.

The display unit <NUM> of the humidity measuring device <NUM> of <FIG> includes the dew point temperature calculation unit <NUM>, the display control unit <NUM>, the display device <NUM>, and a pressure input unit <NUM>. The display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> according to the present embodiment are the same as the display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> of <FIG>.

The pressure input unit <NUM> inputs the pressure of the gas to the dew point temperature calculation unit <NUM>. The pressure of the gas that is output to the dew point temperature calculation unit <NUM> by the pressure input unit <NUM> may be a value set by the user. The pressure of the gas that is output to the dew point temperature calculation unit <NUM> by the pressure input unit <NUM> may be a value set by a manufacturer of the humidity measuring device <NUM> at a time of shipment of the humidity measuring device <NUM>. In the case that the pressure of the compressed gas that flows through the tube <NUM> is substantially constant, a pressure that was set beforehand may be input to the dew point temperature calculation unit <NUM>. Similarly, in the case that the pressure of the compressed gas discharged by the dehumidifying device <NUM> is substantially constant, a pressure that was set beforehand may be input to the dew point temperature calculation unit <NUM>.

The temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM> is input to the dew point temperature calculation unit <NUM>. The pressure of the gas from the pressure input unit <NUM> is input to the dew point temperature calculation unit <NUM>.

The dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas input from the pressure input unit <NUM>, and thereby calculates the dew point temperature under the pressure of the gas.

In the humidity measuring device <NUM> of <FIG>, the dew point temperature calculation unit <NUM> calculates the dew point temperature under atmospheric pressure of the gas, based on the temperature under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>, and the humidity under atmospheric pressure of the gas measured by the temperature and humidity measurement unit <NUM>. The dew point temperature calculation unit <NUM> corrects the dew point temperature under atmospheric pressure of the gas, which was calculated by the dew point temperature calculation unit <NUM>, in accordance with the pressure of the gas input from the pressure input unit <NUM>, and thereby calculates the dew point temperature under the pressure of the gas. Consequently, since the temperature and humidity measurement unit <NUM> does not come into contact with the high pressure gas, the adherence of water droplets to the temperature and humidity measurement unit <NUM> is suppressed.

The display unit <NUM> of the humidity measuring device <NUM> according to the present embodiment includes the display control unit <NUM>, the display device <NUM>, a replacement determination unit <NUM>, and a correction unit <NUM>. The display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> according to the present embodiment are the same as the display control unit <NUM> and the display device <NUM> of the display unit <NUM> of the humidity measuring device <NUM> of <FIG>.

When the dehumidifying device <NUM> is replaced, information indicating that the dehumidifying device <NUM> has been replaced is input from a replacement information input unit <NUM> to the replacement determination unit <NUM>. The replacement information input unit <NUM> is disposed externally of the humidity measuring device <NUM>. The dehumidifying device <NUM> may include the replacement information input unit <NUM>. In the case that information from the replacement information input unit <NUM> indicating that the dehumidifying device <NUM> has been replaced is input to the replacement determination unit <NUM>, the replacement determination unit <NUM> determines that the dehumidifying device <NUM> has been replaced. In the case that information from the replacement information input unit <NUM> indicating that the dehumidifying device <NUM> has been replaced is not input to the replacement determination unit <NUM>, the replacement determination unit <NUM> determines that the dehumidifying device <NUM> has not been replaced.

The humidity of the gas measured by the temperature and humidity measurement unit <NUM> is input to the correction unit <NUM>. The determination result determined by the replacement determination unit <NUM> is also input to the correction unit <NUM>. The correction unit <NUM>, in accordance with the determination result that is input thereto, corrects the humidity measured by the temperature and humidity measurement unit <NUM>.

<FIG> is a flowchart showing a process flow of a correction process executed in the replacement determination unit <NUM> and the correction unit <NUM>. The correction process is repeatedly executed at a predetermined cycle.

In step S1, the replacement determination unit <NUM> determines whether or not the dehumidifying device <NUM> has been replaced, between a time from when the process of step S1 has been executed in a previous cycle until a time when the process of step S1 is executed in the current cycle. When information from the replacement information input unit <NUM> indicating that the dehumidifying device <NUM> has been replaced is input thereto, the replacement determination unit <NUM> determines that the dehumidifying device <NUM> has been replaced. In the case that the replacement determination unit <NUM> has determined that the dehumidifying device <NUM> has been replaced (step S1: YES), the correction process proceeds to step S2. In the case that the replacement determination unit <NUM> has determined that the dehumidifying device <NUM> has not been replaced (step S1: NO), the correction process proceeds to step S6.

In step S2, the correction unit <NUM> determines whether or not the humidity (measured humidity) of the gas measured by the temperature and humidity measurement unit <NUM> is greater than or equal to a first threshold value Th1. In the case that the measured humidity is greater than or equal to the first threshold value Th1 (step S2: YES), the correction process proceeds to step S7. In the case that the measured humidity is less than the first threshold value Th1 (step S2: NO), the correction process proceeds to step S3.

In step S3, the correction unit <NUM> determines whether or not the measured humidity is greater than or equal to a second threshold value Th2. In the case that the measured humidity is greater than or equal to the second threshold value Th2 (step S3: YES), the correction process proceeds to step S4. In the case that the measured humidity is less than the second threshold value Th2 (step S3: NO), the correction process proceeds to step S6. The second threshold value Th2 is a smaller value than the first threshold value Th1.

In step S4, the correction unit <NUM> corrects the measured humidity and thereby obtains a new measured humidity. Thereafter, the correction process proceeds to step S5. Hereinafter, the new measured humidity obtained by the correction unit <NUM> may be referred to as a corrected humidity.

In step S5, the replacement determination unit <NUM> clears the information (dehumidifying device replacement information), which was input from the replacement information input unit <NUM>, indicating that the dehumidifying device <NUM> has been replaced. Thereafter, the correction process proceeds to step S6.

In step S6, the correction unit <NUM> outputs the measured humidity to the display control unit <NUM>. Thereafter, the correction process comes to an end.

In step S7, after it has been determined in step S2 that the measured humidity is greater than or equal to the first threshold value Th1 (step S2: YES), the correction unit <NUM> outputs an error signal to the display control unit <NUM>. Thereafter, the correction process comes to an end. In the case that the error signal is input to the display control unit <NUM>, the display control unit <NUM> controls the display device <NUM> to thereby cause there to be displayed on the display device <NUM> a display prompting the user to replace the temperature and humidity measurement unit <NUM>.

The humidity sensing element of the temperature and humidity measurement unit <NUM> includes a humidity sensitive membrane. A capacitance of the humidity sensitive membrane changes in accordance with an amount of moisture contained within the humidity sensitive membrane. The humidity sensing element measures the humidity of the gas based on the capacitance of the humidity sensitive membrane.

Accompanying deterioration of the humidity sensitive membrane, the capacitance of the humidity sensitive membrane corresponding to the humidity of the gas changes. The reason for this is due to permeation of water into the moisture sensitive membrane, dirt on the humidity sensitive membrane, or the like. Therefore, accompanying the deterioration of the humidity sensitive membrane, the accuracy of the measured humidity as measured by the temperature and humidity measurement unit <NUM> decreases.

Immediately after the dehumidifying device <NUM> has been replaced, it is considered that the humidity of the gas after being dehumidified by the dehumidifying device <NUM> should be adjusted to a predetermined humidity in accordance with the dehumidifying ability of the dehumidifying device <NUM>. In the case that the measured humidity measured by the temperature and humidity measurement unit <NUM> is higher than the predetermined humidity, it is considered that the humidity sensitive membrane has deteriorated.

In the humidity measuring device <NUM> according to the present embodiment, in the case that the replacement determination unit <NUM> has determined that the dehumidifying device <NUM> has been replaced, and in the case that the measured humidity is greater than or equal to the second threshold value and less than the first threshold value, the correction unit <NUM> corrects the measured humidity and thereby obtains the corrected humidity. Consequently, even in the case that the humidity sensitive member is deteriorated, the humidity measuring device <NUM> is capable of maintaining the accuracy of the humidity of the gas.

In the humidity measuring device <NUM> according to the present embodiment, in the case that the replacement determination unit <NUM> has determined that the dehumidifying device <NUM> has been replaced, and in the case that the measured humidity of the temperature and humidity measurement unit <NUM> is greater than or equal to the first threshold value, the display control unit <NUM> controls the display device <NUM> to thereby cause there to be displayed on the display device <NUM> a display prompting the user to replace the temperature and humidity measurement unit <NUM>. Consequently, in the case that the humidity sensitive membrane is severely deteriorated, the humidity measuring device <NUM> is capable of prompting the user to replace the temperature and humidity measurement unit <NUM>.

<FIG> and <FIG> show the humidity measuring device <NUM>. The humidity measuring device <NUM> includes a casing <NUM>, the display unit <NUM>, and a coupling member <NUM>. Cross-sectional views of the casing <NUM> and the coupling member <NUM> are shown in <FIG> and <FIG>. A schematic diagram of the display unit <NUM> is shown in <FIG> and <FIG>.

The casing <NUM> includes a main body portion <NUM> and a connecting portion <NUM>. The main body portion <NUM> includes an accommodating section <NUM> disposed in the interior of the main body portion <NUM>. The accommodating section <NUM> is a space formed inside the main body portion <NUM>.

The humidity measuring device <NUM> includes the electronic circuit board <NUM>. The electronic circuit board <NUM> is arranged between the main body portion <NUM> and the display unit <NUM>. A temperature and humidity measurement unit <NUM> is mounted on the electronic circuit board <NUM>. The temperature and humidity measurement unit <NUM> is accommodated in the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> is an electronic component in which a temperature sensing element and a humidity sensing element are mounted in one single integrated circuit. The temperature sensing element measures the temperature of the gas in the accommodating section <NUM>. The humidity sensing element measures the humidity of the gas in the accommodating section <NUM>. The temperature and humidity measurement unit <NUM> outputs to the display unit <NUM> the temperature and humidity of the gas that were measured.

The connecting portion <NUM> includes a first connecting tube <NUM> and a second connecting tube <NUM>. The first connecting tube <NUM> and the second connecting tube <NUM> are connected to the accommodating section <NUM>. Further, the first connecting tube <NUM> and the second connecting tube <NUM> are connected to a coupling tube <NUM> of the coupling member <NUM>, which will be described later. The gas flows in between the accommodating section <NUM> and the coupling tube <NUM> via the first connecting tube <NUM> and the second connecting tube <NUM>. The cross-sectional area of the first connecting tube <NUM> and the cross-sectional area of the second connecting tube <NUM> are different. As shown in <FIG>, the cross-sectional area of a minimum diameter portion of the second connecting tube <NUM> is smaller than the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM>. As shown in <FIG>, the cross-sectional area of a minimum diameter portion of the first connecting tube <NUM> may be smaller than the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM>.

The coupling member <NUM> includes the coupling tube <NUM> and tube mounting members <NUM> in the interior of the coupling member <NUM>. The coupling tube <NUM> is formed to extend in one direction. The tube mounting members <NUM> are connected respectively to both ends of the coupling tube <NUM>. Each of the tube mounting members <NUM> opens to the exterior of the coupling member <NUM>. The coupling member <NUM> is connected in the middle between tube portions <NUM> (see <FIG>) through which the gas flows. The tube portions <NUM> are connected respectively to the tube mounting members <NUM>. The coupling tube <NUM> is connected between the tube portion <NUM> and the tube portion <NUM>. Consequently, via the coupling tube <NUM>, the gas is capable of flowing between the tube portion <NUM> and the tube portion <NUM>.

A filter <NUM> is mounted in the coupling tube <NUM>. The filter <NUM> is arranged in the connecting portion between the coupling tube <NUM> and the tube mounting member <NUM> that is positioned on the upstream side with respect to the flow of the gas in the coupling tube <NUM>. The coupling tube <NUM> includes an orifice <NUM>. In the orifice <NUM>, the cross-sectional area of a minimum diameter portion of the hole of the orifice <NUM> is smaller than the cross-sectional area of other locations of the coupling tube <NUM>. The orifice <NUM> is arranged more downstream than the filter <NUM> with respect to the flow of the gas in the coupling tube <NUM>. Hereinafter, within the coupling tube <NUM>, the portion thereof located more upstream than the orifice <NUM> may be referred to as a first coupling chamber <NUM>. Further, within the coupling tube <NUM>, the portion thereof located more downstream than the orifice <NUM> may be referred to as a second coupling chamber <NUM>.

The filter <NUM> is mounted on an end part of the upstream side of the coupling tube <NUM>. Due to the filter <NUM>, it becomes possible to remove foreign material mixed in the gas that flows into the coupling tube <NUM>. Consequently, it is possible to prevent such foreign material from entering into the coupling tube <NUM>.

In the first coupling chamber <NUM>, the aforementioned first connecting tube <NUM> is connected to the coupling tube <NUM>. Stated otherwise, the first connecting tube <NUM> is connected to the coupling tube <NUM> at a location between the filter <NUM> and the orifice <NUM>, and at a more upstream location than the orifice <NUM>, with respect to the flow of the gas in the coupling tube <NUM>. In the second coupling chamber <NUM>, the aforementioned second connecting tube <NUM> is connected to the coupling tube <NUM>. Stated otherwise, the second connecting tube <NUM> is connected to the coupling tube <NUM> at a more downstream location than the orifice <NUM>, with respect to the flow of the gas in the coupling tube <NUM>.

<FIG> is a diagram showing a state in which the tube portions <NUM> are connected to the humidity measuring device <NUM>. The arrows in <FIG> indicate the flow of the gas.

Due to the orifice <NUM>, the pressure in the first coupling chamber <NUM> becomes higher than the pressure in the second coupling chamber <NUM>. Consequently, it becomes possible to allow the gas of the coupling tube <NUM> to flow from the first connecting tube <NUM> into the interior of the accommodating section <NUM>. The cross-sectional area corresponding to the diameter of the second connecting tube <NUM> is smaller than the cross-sectional area corresponding to the diameter of the first connecting tube <NUM>. Therefore, the pressure in the accommodating section <NUM> can be made substantially equivalent to the pressure in the first coupling chamber <NUM>.

The gas flows into the accommodating section <NUM> after having passed through the filter <NUM>. Therefore, it is possible to prevent foreign material from entering into the accommodating section <NUM>.

The configuration of the display unit <NUM> is the same as the configuration of the display unit <NUM> of the first embodiment, <FIG>, <FIG>, or <FIG>.

Using a computer, the present inventors performed simulations concerning the humidity in the first coupling chamber <NUM>, the second coupling chamber <NUM>, and the accommodating section <NUM>. <FIG>, <FIG>, and <FIG> are diagrams showing simulation results. <FIG> shows a simulation result for a case in which the cross-sectional area of a minimum diameter portion of the first connecting tube <NUM> and the cross-sectional area of a minimum diameter portion of the second connecting tube <NUM> are equivalent. <FIG> shows a simulation result for a case in which the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM> is smaller than the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM>. <FIG> shows a simulation result for a case in which the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM> is smaller than the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM>. In these simulations, a gas having a humidity of <NUM>% was made to flow into the first coupling chamber <NUM>.

In the case that the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM> and the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM> are equivalent, then as shown in <FIG>, the humidity in the accommodating section <NUM> is lower than the humidity in the first coupling chamber <NUM>. On the other hand, the humidity in the accommodating section <NUM> is higher than the humidity in the second coupling chamber <NUM>. More specifically, the humidity in the accommodating section <NUM> differs from both the humidity in the first coupling chamber <NUM> and the humidity in the second coupling chamber <NUM>. Therefore, although the temperature and humidity measurement unit <NUM> provided in the accommodating section <NUM> is capable of measuring the humidity of the gas that flows through the interior of the tube portions <NUM>, the accuracy of such a measurement is low. Moreover, in this case, the pressure in the accommodating section <NUM> is lower than the pressure in the first coupling chamber <NUM>. On the other hand, the pressure in the accommodating section <NUM> is higher than the pressure in the second coupling chamber <NUM>.

In the case that the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM> is smaller than the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM>, then as shown in <FIG>, the humidity in the accommodating section <NUM> is substantially equivalent to the humidity in the first coupling chamber <NUM>. On the other hand, the humidity in the accommodating section <NUM> is higher than the humidity in the second coupling chamber <NUM>. Therefore, the temperature and humidity measurement unit <NUM> provided in the accommodating section <NUM> is capable of highly accurately measuring the humidity of the gas that flows through the interior of the tube portion <NUM> at a location more upstream than the orifice <NUM>. Moreover, in this case, the pressure in the accommodating section <NUM> is substantially equivalent to the pressure in the first coupling chamber <NUM>. On the other hand, the pressure in the accommodating section <NUM> is higher than the pressure in the second coupling chamber <NUM>.

In the case that the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM> is smaller than the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM>, then as shown in <FIG>, the humidity in the accommodating section <NUM> is substantially equivalent to the humidity in the second coupling chamber <NUM>. On the other hand, the humidity in the accommodating section <NUM> is lower than the humidity in the first coupling chamber <NUM>. Therefore, the temperature and humidity measurement unit <NUM> provided in the accommodating section <NUM> is capable of highly accurately measuring the humidity of the gas that flows through the interior of the tube portion <NUM> at a location more downstream than the orifice <NUM>. Moreover, in this case, the pressure in the accommodating section <NUM> is substantially equivalent to the pressure in the second coupling chamber <NUM>. On the other hand, the pressure in the accommodating section <NUM> is lower than the pressure in the first coupling chamber <NUM>.

The humidity measuring device <NUM> of <FIG> includes the coupling member <NUM> that is connected in the middle between the tube portions <NUM>. The coupling tube <NUM> of the coupling member <NUM> and the accommodating section <NUM> of the casing <NUM> are connected by the first connecting tube <NUM> and the second connecting tube <NUM>. The first connecting tube <NUM> is connected to the coupling tube <NUM> at a location upstream of the orifice <NUM>. The second connecting tube <NUM> is connected to the coupling tube <NUM> at a location downstream of the orifice <NUM>.

In accordance with these features, the gas flowing through the coupling tube <NUM> branches off and flows in a diverted manner, and is delivered from the first connecting tube <NUM> into the accommodating section <NUM>. Therefore, the temperature and humidity measurement unit <NUM> is capable of measuring the humidity of the gas in the accommodating section <NUM>, under the same pressure as in the tube portions <NUM>. As a result, the humidity measuring device <NUM> is capable of measuring the humidity of the gas that flows through the tube portions <NUM>. Further, it is possible to prevent water droplets or the like, which are mixed in the gas that flows through the tube portions <NUM>, from entering into the accommodating section <NUM>. As a result, it is possible to prevent the temperature and humidity measurement unit <NUM> from becoming contaminated.

Further, in the humidity measuring device <NUM> of <FIG>, the gas that flows through the tube portions <NUM> flows from the coupling tube <NUM>, through the first connecting tube <NUM>, and into the accommodating section <NUM>. The gas that has flowed into the accommodating section <NUM> passes through the second connecting tube <NUM>, and is returned to the coupling tube <NUM>. Therefore, the gas that flows through the tube portions <NUM> is not discharged to the exterior. As a result, a decrease in the gas can be suppressed.

In the humidity measuring device <NUM> of <FIG>, the cross-sectional area of the first connecting tube <NUM> and the cross-sectional area of the second connecting tube <NUM> differ from each other. In the case that the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM> is made smaller than the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM>, the temperature and humidity measurement unit <NUM> is capable of highly accurately measuring the humidity of the gas that flows through the interior of the tube portion <NUM> at the location more upstream than the orifice <NUM>. In the case that the cross-sectional area of the minimum diameter portion of the first connecting tube <NUM> is made smaller than the cross-sectional area of the minimum diameter portion of the second connecting tube <NUM>, the temperature and humidity measurement unit <NUM> is capable of highly accurately measuring the humidity of the gas that flows through the interior of the tube portion <NUM> at the location more downstream than the orifice <NUM>.

<FIG> shows the humidity measuring device <NUM>. The humidity measuring device <NUM> includes the casing <NUM>, the display unit <NUM>, and the coupling member <NUM>. In <FIG>, cross-sectional views of the casing <NUM> and the coupling member <NUM> are shown. In <FIG>, a schematic diagram of the display unit <NUM> is shown.

A flow sensor <NUM> is attached to the electronic circuit board <NUM>. The flow sensor <NUM> is accommodated in the accommodating section <NUM> of the casing <NUM>. The flow sensor <NUM> detects the flow rate of the gas that flows through the accommodating section <NUM>. The flow rate of the gas that flows through the tube portions <NUM> can be obtained from the flow rate of the gas that flows through the accommodating section <NUM>. The flow sensor <NUM> is constituted from a sensor, a thermistor, and platinum or the like. The sensor is constituted by a MEMS (Micro Electro Mechanical System). Concerning other constituent features of the humidity measuring device <NUM> of <FIG>, they are the same as those of the humidity measuring device <NUM> of <FIG>.

In the humidity measuring device <NUM> of <FIG>, the flow sensor <NUM> is accommodated in the accommodating section <NUM> of the casing <NUM>. Consequently, the flow rate of the gas that flows through the tube portions <NUM> can be obtained.

<FIG> shows the humidity measuring device <NUM>. The humidity measuring device <NUM> includes the casing <NUM>, the display unit <NUM>, and the coupling member <NUM>. In <FIG>, a cross-sectional view of the casing <NUM> and the coupling member <NUM> is shown. In <FIG>, a schematic diagram of the display unit <NUM> is shown.

The filter <NUM> and a filter <NUM> are mounted in the coupling tube <NUM>. The filter <NUM> is arranged on an opposite side from the filter <NUM> with the orifice <NUM> being interposed therebetween. The filter <NUM> is mounted in a connecting portion between the coupling tube <NUM> and one of the tube mounting members <NUM>. The filter <NUM> is mounted in a connecting portion between the coupling tube <NUM> and another one of the tube mounting members <NUM>.

The filter <NUM> is mounted on one end of the coupling tube <NUM>, and the filter <NUM> is mounted on another end of the coupling tube <NUM>. In accordance with these features, even in the case that the direction in which the gas flows is switched, by the filter <NUM> or the filter <NUM>, it is still possible to remove foreign material mixed in the gas that flows into the coupling tube <NUM>. Consequently, it is possible to prevent such foreign material from entering into the coupling tube <NUM>.

The technical concepts that can be grasped from the above-described embodiment will be described below.

The present invention is characterized by the humidity measuring device (<NUM>) according to claim <NUM>.

In the above-described humidity measuring device, the display unit may include the first output unit (<NUM>) configured to output to the external device (<NUM>) on the external portion of the humidity measuring device at least one of the comparison result of comparing the dew point temperature of the gas with the set dew point temperature, or the comparison result of comparing the humidity of the gas with the set humidity. In accordance with these features, the humidity measuring device is capable of outputting to the external device at least one of the comparison result between the dew point temperature of the gas and the set dew point temperature, or the comparison result between the humidity of the gas and the set humidity.

In the above-described humidity measuring device, the display unit may include the second output unit (<NUM>) configured to output to the external device (<NUM>) on the external portion of the humidity measuring device at least one of the dew point temperature of the gas, or the humidity of the gas. In accordance with this feature, the humidity measuring device is capable of outputting to the external device on the external portion of the humidity measuring device at least one of the dew point temperature of the gas, or the humidity of the gas.

In the above-described humidity measuring device, the casing may include the supply tube (<NUM>) configured to supply the gas at a measurement location where the humidity of the gas is measured into the accommodating section, and the discharge tube (<NUM>) configured to discharge the gas from the accommodating section into the atmosphere, wherein the supply tube and the discharge tube are connected to the accommodating section, in a manner so that a direction in which the gas flows inwardly from the supply tube to the accommodating section, and a direction in which the gas flows outwardly from the accommodating section to the discharge tube are positioned on different straight lines. In accordance with these features, the humidity measuring device is capable of improving the accuracy in measuring the humidity of the gas.

In the above-described humidity measuring device, the casing may include the connecting tube (<NUM>) configured to connect the measurement location and the supply tube to enable the gas to flow between the measurement location and the supply tube, the filter (<NUM>) may be mounted in the connecting tube, the connecting tube may include the orifice (<NUM>), the orifice may be arranged more on a side of the accommodating section than the filter, and the orifice may be formed in a manner so that the cross-sectional area of the hole of the orifice is smaller than the cross-sectional area of the discharge tube. In accordance with these features, the pressure of the gas inside the accommodating section can be made equivalent to the atmospheric pressure.

In the above-described humidity measuring device, the display unit may include the pressure input unit (<NUM>) configured to input the pressure of the gas at the measurement location, and the dew point temperature calculation unit (<NUM>) configured to calculate the dew point temperature under pressure as the dew point temperature, based on the temperature of the gas measured by the temperature sensing element, the humidity of the gas measured by the humidity sensing element, and the pressure of the gas input by the pressure input unit. In accordance with these features, since the measurement unit does not come into contact with the high pressure gas, the adherence of water droplets to the measurement unit is suppressed.

In the above-described humidity measuring device, there may further be included the pressure measurement unit (<NUM>) configured to measure the pressure of the gas at the measurement location, and the display unit may include the dew point temperature calculation unit configured to calculate the dew point temperature under pressure as the dew point temperature, based on the temperature of the gas measured by the temperature sensing element, the humidity of the gas measured by the humidity sensing element, and the pressure of the gas measured by the pressure measurement unit. In accordance with these features, since the measurement unit does not come into contact with the high pressure gas, the adherence of water droplets to the measurement unit is suppressed.

In the above-described humidity measuring device, the casing may include the connecting tube configured to connect the measurement location and the supply tube to enable the gas to flow between the measurement location and the supply tube, the filter may be installed in the connecting tube, the discharge tube may include the orifice (<NUM>), and the orifice may be formed so that the cross-sectional area of the hole of the orifice is smaller than the cross-sectional area of the supply tube. In accordance with these features, the humidity measuring device is capable of filling the interior of the accommodating section with the compressed gas.

In the above-described humidity measuring device, the filter may be made of metal. In accordance with this feature, the humidity measuring device is capable of improving the accuracy in measuring the humidity of the gas.

In the above-described humidity measuring device, the casing may include the main body portion (<NUM>) including the supply tube, and the connecting portion (<NUM>) including the connecting tube, and in a state in which the filter is installed in the connecting portion, the connecting portion may be attached to the main body portion in a manner so that the connecting portion is detachable from the main body portion. In accordance with these features, the user is capable of easily carrying out replacement of the filter of the humidity measuring device.

In the above-described humidity measuring device, the gas at the measurement location where the humidity of the gas is measured is a gas that is discharged from the dehumidifying device (<NUM>) configured to dehumidify the gas, and the display unit includes the replacement determination unit (<NUM>) configured to determine whether or not the dehumidifying device has been replaced, and the correction unit (<NUM>) which, in the case that the humidity of the gas measured by the humidity sensing element is higher than a threshold value immediately after having determined that the dehumidifying device has been replaced, thereafter is configured to correct the humidity of the gas measured by the humidity sensing element, based on the humidity of the gas measured by the humidity sensing element immediately after having determined that the dehumidifying device has been replaced, and the dehumidifying capability of the dehumidifying device that has been replaced. Even in the case that the humidity sensitive membrane is deteriorated, the humidity measuring device is capable of maintaining the accuracy of the humidity of the gas.

In the above-described humidity measuring device, the gas at the measurement location where the humidity of the gas is measured may be a gas that is discharged from the dehumidifying device configured to dehumidify the gas, and the display unit includes the replacement determination unit configured to determine whether or not the dehumidifying device has been replaced, and in the case that the humidity of the gas measured by the humidity sensing element is higher than a threshold value immediately after having determined that the dehumidifying device has been replaced, the display control unit may control the display unit to thereby cause a display to be displayed on the display device, the display prompting the user to replace the measurement unit. In accordance with these features, in the case that the humidity sensitive membrane is severely deteriorated, the humidity measuring device is capable of prompting the user to replace the measurement unit.

In the above-described humidity measuring device, the coupling member (<NUM>) may be connected in the middle between the tube portions (<NUM>) through which the gas flows, the coupling member may include the coupling tube (<NUM>) configured to connect one of the tube portions and another of the tube portions, and which enables the gas to flow between the one tube portion and the other tube portion, the filter (<NUM>) may be mounted in the coupling tube, the coupling tube may include the orifice (<NUM>), with respect to the flow of the gas in the coupling tube, the orifice may be arranged at a location more downstream than the filter, the casing may include the first tube (<NUM>) and the second tube (<NUM>) configured to connect the coupling tube and the accommodating section, and which enable the gas to flow between the coupling tube and the accommodating section, with respect to the flow of the gas in the coupling tube, the first tube is connected to the coupling tube at a location more upstream than the orifice, and between the filter and the orifice, and with respect to the flow of the gas in the coupling tube, the second tube is connected to the coupling tube at a location more downstream than the orifice. In accordance with these features, the humidity measuring device is capable of highly accurately measuring the humidity of the gas that flows through the tube portions.

In the above-described humidity measuring device, the cross-sectional area of the first tube and the cross-sectional area of the second tube may be different. In accordance with this feature, the humidity measuring device is capable of highly accurately measuring the humidity of the gas that flows through the tube portions.

Claim 1:
A humidity measuring device (<NUM>) configured to measure humidity of a gas, the humidity measuring device comprising:
a measurement unit (<NUM>) including a temperature sensing element configured to measure temperature, and a humidity sensing element configured to measure humidity;
a casing (<NUM>) including an accommodating section (<NUM>) in which the measurement unit is accommodated; and
a display unit (<NUM>) including a display device (<NUM>), and which is fixed to the casing,
characterized in that
the gas at the measurement location where the humidity of the gas is measured is the gas that is discharged from a dehumidifying device (<NUM>) configured to dehumidify the gas; and
the display unit further comprises:
a display control unit (<NUM>) configured to control the display device to thereby cause the display device to display at least one of the humidity of the gas measured by the humidity sensing element, or a dew point temperature of the gas calculated based on both the temperature of the gas measured by the temperature sensing element and the humidity of the gas measured by the humidity sensing element;
a replacement determination unit (<NUM>) configured to determine whether or not the dehumidifying device has been replaced; and
a correction unit (<NUM>) which, in a case that the humidity of the gas measured by the humidity sensing element is higher than a threshold value immediately after having determined that the dehumidifying device has been replaced, thereafter, is configured to correct the humidity of the gas measured by the humidity sensing element, based on the humidity of the gas measured by the humidity sensing element immediately after having determined that the dehumidifying device has been replaced, and a dehumidifying capability of the dehumidifying device that has been replaced.