Patent Description:
In the related art, two lines, one for cold water and the other for hot water, are connected to a water discharge port provided in a lavatory or the like in an aircraft, and it is possible to switch the temperature or adjust the temperature to an intermediate temperature according to the user's preference.

As a method for adjusting the temperature to an intermediate temperature, a manual (dial) type has been adopted in the old model, and a button-based multi-stage (for example, <NUM>-step) switching method and the like have been adopted recently.

Most of the button-based multi-step methods are electronically controlled, and for example, a method of changing the actual flow rate ratio by changing the duty ratio of a solenoid valve (ON-OFF valve) between hot water and cold water has been proposed.

For example, in Patent Document <NUM> described below, a mixing means is provided with a first solenoid valve and a second solenoid valve individually connected to a cold water inlet port and a hot water inlet port, a control signal reflecting the temperature specified by a temperature adjusting means is transmitted to the mixing means via a control wire, and a duty ratio of each of the first solenoid valve and the second solenoid valve is changed based on the specified temperature, whereby the water temperature of the mixed water is adjusted.

However, temperature of both cold water and hot water is not constant due to environmental factors within aircrafts (for example, flight altitude (outside air temperature), heater performance for hot water, continuous hot water usage, and the like). Thus, even if cold water and hot water are mixed by controlling the electromagnetic valve according to the conventional method, the temperature of the water supplied to a water discharge port will not be constant. In other words, even when the temperature is set by a user, the relative water temperature can be adjusted, but there is a problem that it is difficult to supply water at a certain temperature.

In light of the foregoing, an object of the present invention is to enable water to be used in an aircraft to be supplied at a desired temperature. Document <CIT> discloses an aircraft water supply system according to the preamble of claim <NUM>.

In order to attain the object, the present invention provides an aircraft water supply system for supplying water to a water discharge port in an aircraft according to claim <NUM>.

According to the present invention, since the flow rate of cold water and hot water (the opening/closing state of the first control valve and the second control valve) is controlled based on the water temperature detected by the temperature sensors, which is advantageous in controlling the temperature of the water to be discharged from the water discharge port with high accuracy as compared with a case where the temperature sensors are not used.

Aircraft water supply systems according to preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

<FIG> is a diagram illustrating a configuration of an aircraft water supply system <NUM> not belonging to the invention.

The aircraft water supply system <NUM> supplies water to a water discharge port <NUM> in an aircraft. The water discharge port <NUM> is installed in a lavatory, a galley, or the like in an aircraft, for example, and provides users with water for hand washing or drinking.

In the present case, it is assumed that the water discharge port <NUM> is installed in a lavatory inside an aircraft. A hand wash faucet (the water discharge port <NUM> in the present embodiment) in a lavatory is used by an unspecified number of boarding passengers, and there are various demands for water temperature as compared with a faucet such as a galley used by a limited number of users.

The discharge of the water from the water discharge port <NUM> is switched on/off by operating a discharge instruction unit <NUM>. The discharge instruction unit <NUM> is a mechanism such as a sensor, a cock, a switch, or the like provided in the vicinity of the water discharge port <NUM>. For example, the discharge instruction unit <NUM> may be configured as an automatic faucet such that an infrared sensor is used as the discharge instruction unit <NUM>, a user's hand is detected by the infrared sensor, and water is discharged when the user's hand is held over. Alternatively, the discharge instruction unit <NUM> may be configured as a manual faucet such that a cock or a switch is used as the discharge instruction unit <NUM> and water is discharged for a predetermined period in response to the user operating the cock or the switch.

The temperature specifying unit <NUM> is disposed near the water discharge port <NUM>, for example, and a user can specify the temperature of the water to be discharged from the water discharge port <NUM>. The temperature specifying unit <NUM> may employ a button-based multi-stage switching system, a dial-based continuous switching system, or the like.

Note that the temperature specifying unit <NUM> may not be provided, and the water temperature may be maintained at a predetermined set temperature (fixed value).

The water supplied to the water discharge port <NUM> is stored in a water tank <NUM> installed in an aircraft. In addition to the water W, the compressed air A is supplied to the water tank <NUM>, and the water W is extruded toward the water discharge port <NUM> by the pressure from the compressed air A. The temperature of the water W inside the water tank <NUM> varies depending on the temperature and the like around the tank.

The water flow path from the water tank <NUM> to the water discharge port <NUM> includes a cold water flow path <NUM>, a hot water flow path <NUM>, and a mixing flow path <NUM>. In the present embodiment, a main valve (a shutoff valve) <NUM> is first provided downstream from the water tank <NUM>. The main valve <NUM> is a valve for disconnecting the water tank <NUM> and the flow paths in the event of abnormalities. The cold water flow path <NUM> and the hot water flow path <NUM> are branched downstream from the main valve <NUM>.

Note that the cold water flow path <NUM> and the hot water flow path <NUM> may be connected directly to the water tank <NUM>. In this case, main faucets (a cold water faucet and a hot water faucet) may be provided at positions near the water tank <NUM> of the cold water flow path <NUM> and the hot water flow path <NUM>, respectively.

The cold water flow path <NUM> is a flow path for supplying cold water to the water discharge port <NUM>, and is a flow path through which the water W in the water tank <NUM> flows as it is (without being heated). In the present embodiment, the cold water flow path <NUM> connects the water tank <NUM> and the mixing tank <NUM>.

The hot water flow path <NUM> is a flow path for supplying hot water to the water discharge port <NUM>. In the present case, the hot water flow path <NUM> connects the water tank <NUM> and the mixing tank <NUM>. A water heater (WH) <NUM> is provided in the hot water flow path <NUM>. A heating material is provided in the water heater <NUM>, and water flowing through the hot water flow path <NUM> is heated by the water heater <NUM> to become hot water, and the hot water is supplied to the water discharge port <NUM>. The temperature of the hot water heated by the water heater <NUM> varies depending on factors, for example, such as the temperature of the water W in the water tank <NUM>, the heating performance of the water heater <NUM>, the amount of continuous hot water used (the higher the continuous hot water usage, the lower the heating performance).

In the mixing tank <NUM>, the cold water flowing through the cold water flow path <NUM> and the hot water flowing through the hot water flow path <NUM> are mixed.

The mixing flow path <NUM> connects the mixing tank <NUM> and the water discharge port <NUM>, and the mixed water of cold water and hot water mixed in the mixing tank <NUM> flows through the mixing flow path <NUM>.

In the present case, the components ranging from the mixing tank <NUM> to the mixing flow path <NUM> form a mixing supply unit <NUM>. The mixing supply unit <NUM> mixes cold water and hot water downstream from the first control valve <NUM> and the second control valve <NUM>, which will be described later, and supplies the mixed water to the water discharge port <NUM>.

The mixing flow path <NUM> is provided with a constant flow valve <NUM> that makes the amount of water supplied to the water discharge port <NUM> constant. As a result, the amount of the water discharged from the water discharge port <NUM> becomes constant. The constant flow valve <NUM> maintains the amount of water supplied to the downstream side to be constant by widening the water channel when the water pressure on the upstream side is low and narrowing the water channel when the water pressure on the upstream side is high.

In this case, the temperature sensor <NUM> detects the water temperature at any point from the water tank <NUM> to the water discharge port <NUM>. In the present case, the temperature sensor <NUM> is provided in the mixing supply unit <NUM> to detect the water temperature in a state in which cold water flowing through the cold water flow path <NUM> and hot water flowing in the hot water flow path <NUM> are mixed. In <FIG>, the temperature sensor <NUM> is provided downstream from the mixing tank <NUM> and on the mixing flow path <NUM> upstream from the constant flow valve <NUM>, but the temperature sensor <NUM> may be provided, for example, in the mixing tank <NUM>, or downstream from the constant flow valve <NUM>.

The detection value of the temperature sensor <NUM> is output to the flow control unit <NUM>, which will be described later.

The cold water flow path <NUM> and the hot water flow path <NUM> are each provided with a control valve for adjusting the flow rate of water flowing through each of the flow paths.

That is, a first control valve <NUM> that adjusts the flow rate of cold water flowing through the cold water flow path <NUM> and a second control valve <NUM> that adjusts the flow rate of hot water flowing through the hot water flow path <NUM> are provided.

The first control valve <NUM> and the second control valve <NUM> are, for example, solenoid valves, and in the present case, are proportional control valves of which the degree of valve opening depends on an input current value.

The type of the valves used as the first control valve <NUM> and the second control valve <NUM> are not particularly limited as long as the flow rate of water flowing through each of the flow paths can be adjusted. When a proportional control valve is used, the degree of valve opening can be adjusted arbitrarily (continuously), and the flow rate in each of the flow paths can be adjusted with higher accuracy.

As another example of the valves used as the first control valve <NUM> and the second control valve <NUM>, an ON-OFF valve of which the opening time (or closing time) per unit time can be adjusted by changing the duty ratio can be used.

The flow control unit <NUM> (controller) controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> based on the water temperature detected by the temperature sensor <NUM>. In the present case, the temperature sensor <NUM> is provided in the mixing supply unit <NUM>. In this case, the flow control unit <NUM> controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> based on the water temperature in the mixing supply unit <NUM>.

The flow control unit <NUM> controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> based on the temperature specified by the temperature specifying unit <NUM>. In other words, the opening/closing state of each of the control valves <NUM> and <NUM> is controlled so that the temperature of the water discharged from the water discharge port <NUM> reaches the temperature specified by the temperature specifying unit <NUM> (hereinafter referred to as the "specified water temperature").

Note that when the temperature specifying unit <NUM> is not provided, the opening/closing state of the first control valve <NUM> and the second control valve <NUM> is controlled based on a predetermined set temperature (fixed value). In other words, the opening/closing state of each of the control valves <NUM> and <NUM> is controlled so that the temperature of the water discharged from the water discharge port <NUM> reaches a set temperature.

In the present case, since the temperature sensor <NUM> is provided in the mixing supply unit <NUM>, the detection value of the temperature sensor <NUM> is approximately equal to the temperature of the water discharged from the water discharge port <NUM>. Thus, for example, when the detection value of the temperature sensor <NUM> is higher than the specified water temperature, the flow control unit <NUM> controls the first control valve <NUM> (the cold water side) to the opening direction and controls the second control valve <NUM> (the hot water side) to the closing direction so that the amount of the cold water flowing toward the mixing tank <NUM> is increased and the amount of the hot water flowing toward the mixing tank <NUM> is decreased. Further, for example, when the detection value of the temperature sensor <NUM> is lower than the specified water temperature, the flow control unit <NUM> controls the first control valve <NUM> (the cold water side) to the closing direction and controls the second control valve <NUM> (the hot water side) to the opening direction so that the amount of the cold water flowing toward the mixing tank <NUM> is decreased and the amount of the hot water flowing toward the mixing tank <NUM> is increased.

Note that the flow control unit <NUM> may adjust any one of the first control valve <NUM> and the second control valve <NUM> (the hot water side). For example, when the detection value of the temperature sensor <NUM> is higher than the specified water temperature, the first control valve <NUM> (the cold water side) may be controlled to the opening direction without changing the degree of opening of the second control valve <NUM> (the hot water side), and the second control valve <NUM> (the hot water side) may be controlled to the closing direction without changing the degree of opening of the first control valve <NUM> (the cold water side).

On the other hand, when only one of the first control valve <NUM> and the second control valve <NUM> is adjusted, there is a possibility that the amount of water supplied to the mixing supply unit <NUM> fluctuates. Thus, the flow control unit <NUM> may control the opening/closing state of the first control valve <NUM> and the second control valve <NUM> so that the sum of the flow rate of the cold water flowing through the cold water flow path <NUM> and the flow rate of the hot water flowing through the water flow path <NUM> is substantially constant during the use of a hand wash faucet (that is, during the discharge of water from the water discharge port <NUM>).

When the temperature specifying unit <NUM> is not provided, the flow control unit <NUM> controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> so that the detection value of the temperature sensor <NUM> reaches a predetermined set temperature (fixed value).

<FIG> is a flowchart illustrating processing of the flow control unit <NUM> in the present case.

In an initial state, the target degree of valve opening of the first control valve <NUM> and the second control valve <NUM> are each set to a predetermined initial setting value (step S200).

When a temperature specifying operation (change in the specified water temperature or the like) is performed on the temperature specifying unit <NUM> (step S202: Yes), the flow control unit <NUM> sets the target temperature of the water to be discharged from the water discharge port <NUM> to the specified water temperature (the temperature presently specified for the temperature specifying unit <NUM>) (step S204). Additionally, when the specifying operation is not performed on the temperature specifying unit <NUM> (step S202: No), the target temperature is maintained at the current temperature setting (step S206).

Until an operation (discharge ON operation) is performed on the discharge instruction unit <NUM> and passing of water is performed (step S208: No loop), the process returns to step S202 and the subsequent processing is continued.

When an operation (discharge ON operation) is performed on the discharge instruction unit <NUM>, the flow control unit <NUM> opens the first control valve <NUM> and the second control valve <NUM> to the target degree of valve opening set in step S200, and starts passing water (step S208: Yes).

The flow control unit <NUM> acquires the detection value of the temperature sensor <NUM> (step S210), and determines whether the current water temperature (current temperature) in the mixing supply unit <NUM> is within the range of target temperature ± α (α is a predetermined allowable value) (step S212).

When the current temperature is not in the range of target temperature ± α (step S212: No), the flow control unit <NUM> changes the degrees of valve opening of the first control valve <NUM> and the second control valve <NUM> so that the water temperature in the mixing supply unit <NUM> approaches the target temperature (step S214). Specifically, for example, as described above, when the current temperature is higher than the target temperature, the first control valve <NUM> (the cold water side) is controlled to the opening direction and the second control valve <NUM> (the hot water side) is controlled to the closing direction. Further, for example, when the current temperature is lower than the target temperature, the first control valve <NUM> (the cold water side) is controlled to the closing direction, and the second control valve <NUM> (the hot water side) is controlled to the opening direction.

When the current temperature is in the range of the target temperature ± α (step S212: Yes), the flow control unit <NUM> maintains the degrees of valve opening of the first control valve <NUM> and the second control valve <NUM> in the current state (step S216).

Until an operation (discharge OFF operation) is performed on the discharge instruction unit <NUM> and passing of water ends (step S218: No loop), the process returns to step S202 and the subsequent processing is continued. For example, when an operation of changing the specified water temperature is performed during the discharge of water, the target temperature is changed to the specified water temperature after change.

Then, when an operation (discharge OFF operation) is performed on the discharge instruction unit <NUM>, the first control valve <NUM> and the second control valve <NUM> are fully closed to end passing of water (step S218: Yes), and the processing of this flowchart ends.

In the aircraft water supply system <NUM> described above, since the flow rate of cold water and hot water (the opening/closing state of the first control valve <NUM> and the second control valve <NUM>) is controlled based on the water temperature detected by the temperature sensor <NUM>, which is advantageous in controlling the temperature of the water to be discharged from the water discharge port <NUM> with high accuracy as compared with a case where the temperature sensor <NUM> is not used.

In addition, in the aircraft water supply system <NUM>, since the temperature sensor <NUM> is provided in the mixing supply unit <NUM>, it is possible to detect the temperature of the mixed water of cold water and hot water (that is, the temperature of water in a state near the water to be discharged from the water discharge port <NUM>), which is advantageous in adjusting the water temperature to the desired water temperature with high accuracy.

Furthermore, the aircraft water supply system <NUM> controls the opening/closing state of the control valves <NUM> and <NUM> based on the temperature specified by the temperature specifying unit <NUM>, which is advantageous in providing water at a temperature desired by the user.

Furthermore, the aircraft water supply system <NUM> uses a proportional control valve as the first control valve <NUM> and the second control valve <NUM>, which is advantageous in adjusting the flow rates of cold water and hot water with high accuracy.

According to the invention, the cold water flow path <NUM> and the hot water flow path <NUM> each comprise a temperature sensor (36A,36B).

<FIG> is a diagram illustrating a configuration of an aircraft water supply system <NUM> according to an embodiment of the invention.

In the configuration illustrated in <FIG>, the same parts as those in <FIG> are denoted by the same reference signs, and detailed description thereof will be omitted.

In the aircraft water supply system <NUM> according to the invention, the temperature sensors <NUM> (36A, 36B) are provided in the cold water flow path <NUM> and the hot water flow path <NUM>, respectively. The temperature sensor provided in the cold water flow path <NUM> is referred to as a temperature sensor 36A, and a temperature sensor provided in the hot water flow path <NUM> is referred to as a temperature sensor 36B.

Note that in the example of <FIG>, the temperature sensor 36A is provided in the water flow path <NUM> downstream from the water tank <NUM> and upstream from the first control valve <NUM>, and the temperature sensor 36B is provided in the hot water flow path <NUM> at a location downstream from the water heater <NUM> and upstream from the second control valve <NUM>.

The flow control unit <NUM> acquires the detection values of the temperature sensor 36A and the temperature sensor 36B, and controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> based on the temperature of the cold water flowing through the cold water flow path <NUM> and the temperature of the hot water flowing through the hot water flow path <NUM>.

That is, the temperature of the mixed water when a plurality of components of water having different temperatures are mixed by a predetermined amount can be predicted with a certain accuracy. Thus, the flow control unit <NUM> controls the mixing ratio (≈ the degree of valve opening) of the cold water and the hot water based on the temperatures of the cold water and the hot water acquired from the temperature sensors 36A and 36B so that the mixed water of cold water and hot water is at a target temperature.

Note that the flow control unit <NUM> predicts the change in temperature of the cold water and hot water downstream from the temperature sensors 36A and 36B, based on the thermal conductivity of the material of components (for example, the mixing tank <NUM> and the mixing flow path <NUM>) downstream from the temperature sensors 36A and 36B or the temperature around the components and control the opening/closing state of the first control valve <NUM> and the second control valve <NUM> by taking the predicted change in temperature into consideration.

Furthermore, as illustrated in <FIG> for example, a temperature sensor 36C may be provided in the mixing supply unit <NUM> in addition to the temperature sensors 36A and 36B. In this case, the flow control unit <NUM> controls the opening/closing state of the first control valve <NUM> and the second control valve <NUM> based on the temperature of the cold water flowing through the cold water flow path <NUM>, the temperature of the hot water flowing through the hot water flow path <NUM>, and the water temperature in the mixing supply unit <NUM>.

For example, the flow control unit <NUM> determines a degree of valve opening changing direction based on the temperature of the mixed water acquired from the temperature sensor 36C so that the mixed water of cold water and hot water is at a target temperature. Furthermore, the flow control unit <NUM> determines the amount of change in the degree of valve opening based on the temperatures of the cold water and the hot water obtained from the temperature sensors 36A and 36B. Thus, for example, when the detection value of the temperature sensor 36C is higher than the target temperature, the flow control unit <NUM> determines that the first control valve <NUM> (the cold water side) is controlled to the opening direction and the second control valve <NUM> (the hot water side) is controlled to the closing direction. Specifically, how much the valve opening is to be changed is determined based on the temperatures of cold water and hot water acquired from the temperature sensors 36A and 36B.

In this way, by using three temperature sensors <NUM>, the temperature of the water discharged from the water discharge port <NUM> can be brought closer to the target temperature with higher accuracy.

<FIG> is a flowchart illustrating processing of the flow control unit <NUM> in the configuration illustrated in <FIG>.

In an initial state, the target degrees of valve opening of the first control valve <NUM> and the second control valve <NUM> are each set to a predetermined initial setting value (step S500).

When a temperature specifying operation (change in the specified water temperature or the like) is performed on the temperature specifying unit <NUM> (step S504: Yes), the flow control unit <NUM> sets the target temperature of the water to be discharged from the water discharge port <NUM> to the specified water temperature (the temperature presently specified for the temperature specifying unit <NUM>) (step S506). Additionally, when the specifying operation is not performed on the temperature specifying unit <NUM> (step S504: No), the target temperature is maintained at the current temperature setting (step S508).

Until an operation (discharge ON operation) is performed on the discharge instruction unit <NUM> and passing of water is performed (step S509: No loop), the process returns to step S504 and the subsequent processing is continued.

When an operation (discharge ON operation) is performed on the discharge instruction unit <NUM>, the flow control unit <NUM> opens the first control valve <NUM> and the second control valve <NUM> to the target degrees of valve opening set in step S200, and starts passing water (step S509: Yes).

The flow control unit <NUM> acquires the detection values of the temperature sensors 36A and 36B (step S510), and determines the target degrees of valve opening of the first control valve <NUM> and the second control valve <NUM> based on the cold water temperature and the hot water temperature acquired from the temperature sensors 36A and 36B, and the target temperature (step S512). Specifically, the mixing ratio of cold water and hot water is calculated such that the mixed water of cold water and hot water is at a target temperature, and the degree of valve opening is calculated such that cold water and hot water flowing on the mixing supply unit <NUM> side have the mixing ratio.

Then, the degrees of valve opening of the first control valve <NUM> and the second control valve <NUM> are changed to match the target degrees of valve opening (step S514).

Until an operation (discharge OFF operation) is performed on the discharge instruction unit <NUM> and passing of water ends (step S516: No loop), the process returns to step S504 and the subsequent processing is continued. For example, when an operation of changing the specified water temperature is performed during the discharge of water, the target temperature is changed to the specified water temperature after change.

Then, when an operation (discharge OFF operation) is performed on the discharge instruction unit <NUM>, the first control valve <NUM> and the second control valve <NUM> are fully closed to end passing of water (step S516: Yes), and the processing of this flowchart ends.

In other words, in the aircraft water supply system <NUM>, the temperature sensors 36A and 36B are provided in the cold water flow path <NUM> and the hot water flow path <NUM>, respectively, which is advantageous in adjusting the mixing ratio at the stage of mixing cold water and hot water and adjusting the temperature of the water to be discharged from the water discharge port <NUM> to a desired water temperature.

Claim 1:
An aircraft water supply system (<NUM>) for supplying water to a water discharge port (<NUM>) in an aircraft, the system comprising:
a cold water flow path (<NUM>) that supplies cold water to the water discharge port (<NUM>);
a hot water flow path (<NUM>) that supplies hot water to the water discharge port (<NUM>);
a first control valve (<NUM>) that adjusts a flow rate of the cold water flowing through the cold water flow path (<NUM>);
a second control valve (<NUM>) that adjusts a flow rate of the hot water flowing through the hot water flow path (<NUM>);
at least one temperature sensor (<NUM>, 36A, 36B, 36C) that detects a water temperature at any point up to the water discharge port (<NUM>); and
a flow control unit (<NUM>) that controls an opening/closing state of the first control valve (<NUM>) and the second control valve (<NUM>) based on the water temperature detected by the at least one temperature sensor (<NUM>,36A,36B,36C);
characterized in that
the cold water flow path (<NUM>) and the hot water flow path (<NUM>) each comprise a temperature sensor (36A, 36B), and the flow control unit (<NUM>) controls the opening/closing state of the first control valve (<NUM>) and the second control valve (<NUM>) based on the detected temperature of the cold water flowing through the cold water flow path (<NUM>) and based on the detected temperature of the hot water flowing through the hot water flow path (<NUM>);
wherein the system (<NUM>) comprises a component (<NUM>,<NUM>) downstream from the temperature sensors (36A,36B) and the flow control unit (<NUM>) predicts a change in temperature of the cold water and the hot water downstream from the temperature sensors (36A, 36B) based on at least one of a thermal conductivity of the component (<NUM>, <NUM>) or a temperature around the component (<NUM>, <NUM>), and wherein the flow control unit (<NUM>) controls the opening/closing state of the first control valve (<NUM>) and the second control valve (<NUM>) by taking the change in temperature into consideration.