Patent Description:
A conventionally known pressure detection device includes a flow passage unit provided with a pressure transmitting surface formed on a part of a flow passage that allows liquid to flow therethrough, a pressure detection unit that detects pressure transmitted to a pressure detecting surface, and a mounting mechanism by which these units are removably mounted (see, for example, <CIT>).

In the pressure detection device disclosed in <CIT>, the flow passage unit is removably mounted on the pressure detection unit, and thus a used flow passage unit can be replaced with a new flow passage unit.

When a flow passage unit is replaced, the pressure transmitting surface of a used flow passage unit separates from the pressure detecting surface of the pressure detection unit, and a pressure transmitting surface of a new flow passage unit then comes into contact with a pressure detecting surface of the pressure detection unit.

In the pressure detection device disclosed in <CIT>, the internal thread formed in the inner circumferential surface of a nut rotatably attached to the flow passage unit is screwed onto the external thread of the flow passage unit, and thereby the pressure detecting surface of a pressure sensor comes into contact with the pressure transmitting surface of the flow passage unit.

In the pressure detection device disclosed in <CIT>, however, the strength of force to cause the pressure detecting surface of the pressure detection unit and the pressure transmitting surface of the flow passage unit to come into contact with each other depends on the strength of the operator's force to screw the internal thread of the nut and the external thread of the flow passage unit with each other. Thus, it is not possible to have always the same strength of force to cause the pressure detecting surface of the pressure detection unit to come into contact with the pressure transmitting surface of the flow passage unit, and the pressure detection characteristics obtained by the pressure detection unit may vary.

<CIT> discloses is a pressure detection device which includes: a pressure detection unit configured to detect a pressure transmitted to a diaphragm; a flow passage unit in which a flow passage and a diaphragm are formed, a fluid being made to flow through the flow passage along a flow direction from an inflow port to an outflow port, and the diaphragm being configured to transmit a pressure of the fluid flowing through the flow passage to the diaphragm; and a nut configured to allow the flow passage unit to be detachably mounted on the pressure detection unit. The pressure detection unit includes a mounting detection sensor configured to detect that the flow passage unit is mounted on the pressure detection unit in a state where the diaphragm and the diaphragm are in contact with each other.

<CIT> discloses a sensor case which includes a body portion having a circular horizontal section. An upper body includes an accommodation space having a wall surface having a circular horizontal section, and the body portion is inserted in the accommodation space such that the body portion is capable of rotating about a central axis thereof extending in a vertical direction. A stopper is arranged to project in a horizontal direction in an outer circumferential surface of the body portion. A guide groove is arranged to extend in the vertical direction at the wall surface of the accommodation space, and is arranged to allow the stopper to move therein. The upper body includes a restricting portion arranged to restrict a vertical movement of the stopper.

The present invention has been made in view of such circumstances and intends to prevent variation of the pressure detection characteristics obtained by a pressure detection unit in a pressure detection device including a mounting unit used for removably mounting a flow passage unit on the pressure detection unit.

To solve the problem described above, the present invention employs the following solutions.

A pressure detection device according to the claimed invention is defined in independent claim <NUM>.

According to the pressure detection device of one aspect of the present invention, since the flow passage unit is removably mounted on the pressure detection unit, when a fluid to be passed through the flow passage is changed, a used flow passage unit may be removed from the pressure detection unit, and an unused flow passage unit may be newly mounted on the pressure detection unit. Thus, when a fluid to be passed through the flow passage is changed, cleaning work for the flow passage that would otherwise take a long time is no longer required, and the speed of work can be increased. Further, since an unused flow passage unit can be newly used, safety can be enhanced.

Further, according to the pressure detection device of one aspect of the present invention, the mounting unit mounts the flow passage unit on the pressure detection unit with the pressure detecting surface being in contact with the pressure transmitting surface under the urging force generated by the urging unit. Since the pressure detecting surface is in contact with the pressure transmitting surface under the urging force generated by the urging unit, the strength of force with which the pressure detecting surface contacts the pressure transmitting surface is always the same, and this can prevent variation of the pressure detection characteristics obtained by the pressure detection unit.

The pressure detection device according to one aspect of the present invention is preferably configured such that the holding unit has a protrusion protruding in a direction orthogonal to the axis, the mounting unit is mounted on the flow passage unit rotatably about the axis and has a groove configured to accept the protrusion, the groove has a first groove extending in the axis and having an open one end, and a second groove connected to the other end of the first groove and extending circumferentially about the axis, and the sensor unit is positioned at a predetermined position on the axis when the second groove is pressed against the protrusion by the urging force generated by the urging unit.

According to the pressure detection device of the configuration described above, when the operator holds the mounting unit rotatably mounted on the flow passage unit and presses the mounting unit against the pressure detection unit in a state where the circumferential positions of the first groove and the protrusion are matched, thereby the protrusion is inserted in the first groove. When the mounting unit is pressed against the pressure detection unit, the pressure detecting surface is in contact with the pressure transmitting surface under the urging force generated by the urging unit.

The operator then rotates the mounting unit within a range less than one turn about the axis, thereby the protrusion is inserted in the second groove connected to the first groove, and the sensor unit is positioned at a predetermined position on the axis. The state where the pressure detecting surface is in contact with the pressure transmitting surface under the urging force generated by the urging unit is maintained with the sensor unit being positioned.

The operator is able to mount the flow passage unit on the pressure detection unit by a relatively easy operation of pressing the mounting unit against the pressure detection unit and then rotating the mounting unit within a range less than one turn about the axis. Further, it is possible to remove the flow passage unit from the pressure detection unit by a relatively easy operation of rotating the mounting unit within a range less than one turn about the axis in the reverse direction. It is therefore possible to quickly mount and remove the flow passage unit on and from the pressure detection unit compared to a case where the operator rotates a nut about the axis for multiple times to mount and remove the flow passage unit on and from the pressure detection unit as with the case of <CIT>.

The pressure detection device of the configuration described above is preferably configured such that the second groove has a recess formed in a shape corresponding to an outer circumferential surface of the protrusion, and the mounting unit is restricted from rotating about the axis when the recess is pressed against the protrusion by the urging force generated by the urging unit.

According to the pressure detection device of the configuration described above, the operator rotates the mounting unit about the axis to arrange the recess of the second groove at the position of the protrusion, and thereby the recess is pressed against the protrusion by the urging force generated by the urging unit. Since the recess is formed in a shape corresponding to the shape of the protrusion, once the recess is pressed against the protrusion, the mounting unit is restricted from being rotated about the axis and is locked.

Thus, unless the operator presses and rotates the mounting unit about the axis with pressing force against the urging force applied by the urging unit, the flow passage unit is not removed from the pressure detection unit. It is thus possible to reliably maintain the state where the flow passage unit is mounted on the pressure detection unit.

The pressure detection device according to one aspect of the present invention is preferably configured to include a sensing unit configured to detect that circumferential positions about the axis of the recess and the protrusion are matched.

By using the sensing unit to detect that the circumferential positions about the axis of the recess and the protrusion are matched, it is possible to detect that the flow passage unit is secured on the pressure detection unit.

The pressure detection device of the configuration described above is preferably configured such that a magnet is attached to any one of the pressure detection unit and the mounting unit, and the sensing unit is attached to the other of the pressure detection unit and the mounting unit, detects that the magnet is arranged at a proximate position, and when the circumferential positions about the axis of the recess and the protrusion are matched, the magnet is arranged at the proximate position.

According to the pressure detection device of the configuration described above, when the circumferential positions about the axis of the recess and the protrusion are matched, the sensing unit attached to any one of the pressure detection unit and the mounting unit detects that the magnet attached to the other of the pressure detection unit and the mounting unit is arranged at a proximate position. Accordingly, it is possible to reliably detect a state where the flow passage unit is mounted on the pressure detection unit.

The pressure detection device according to one aspect of the present invention is preferably configured such that the mounting unit has a knob extending in a direction orthogonal to the axis and configured to enable an operator to apply, in a direction along the axis, pressing force against the urging force generated by the urging unit.

According to the pressure detection device described above, the operator is able to easily mount the flow passage unit to the pressure detection unit by applying pressing force via the knob against the urging force generated by the urging unit to the mounting unit.

According to the present invention, it is possible to prevent variation of the pressure detection characteristics obtained by a pressure detection unit in a pressure detection device including a mounting unit used for removably mounting a flow passage unit on the pressure detection unit.

With reference to the drawings, a pressure detection device <NUM> according to an embodiment of the present disclosure is described below.

As shown in <FIG> and <FIG>, the pressure detection device <NUM> according to this embodiment includes a pressure detection unit <NUM>, a flow passage unit <NUM>, and a mounting unit <NUM>. The pressure detection unit <NUM> is mounted on an installation surface S (see <FIG>) by fastening bolts (not shown). The flow passage unit <NUM> includes a flow passage <NUM> formed therein to allow liquid (fluid) to flow through the flow passage <NUM> along a straight-line flow direction from an inflow port 21a to an outflow port 21b. The mounting unit <NUM> allows the flow passage unit <NUM> to be removably mounted on the pressure detection unit <NUM>.

In the pressure detection device <NUM> according to this embodiment, the flow passage unit <NUM> is mounted on the pressure detection unit <NUM> by the mounting unit <NUM>. The pressure detection device <NUM> is mounted on the installation surface S in a state where the flow passage unit <NUM> is mounted integrally on the pressure detection unit <NUM> by the mounting unit <NUM>.

As shown in <FIG>, the inflow port 21a of the flow passage unit <NUM> is attached to an inflow pipe (not shown) that allows fluid to flow in the inflow port 21a. The outflow port 21b of the flow passage unit <NUM> is attached to an outflow pipe (not shown) that allows fluid flowing out from the outflow port 21b to flow therethrough. The pressure detection unit <NUM> detects pressure of fluid flowing through the flow passage <NUM> from the inflow port 21a to the outflow port 21b. In this embodiment, fluid means liquid such as blood or a dialysate.

As shown in <FIG>, the pressure detection unit <NUM> includes a body <NUM> mounted on the installation surface S. As shown in <FIG> and <FIG>, on the body <NUM> of the pressure detection unit <NUM>, a cable <NUM> is mounted via a cable mounting nut 50a. The cable <NUM> electrically connects a sensor unit <NUM> arranged in the body <NUM> to a control device (not shown) arranged outside the body <NUM>.

Next, the pressure detection unit <NUM> will be described in detail with reference to <FIG>. The pressure detection unit <NUM> illustrated in <FIG> is a device that detects the pressure of a fluid transferred to a pressure detecting surface 12aA. <FIG> is a front view illustrating a state where the flow passage unit <NUM> has been removed from a pressure detection unit <NUM> illustrated in <FIG>. <FIG> illustrates a partial cross section of the flow passage unit <NUM> and the mounting unit <NUM> illustrated in <FIG>. <FIG> is a longitudinal sectional view of the pressure detection unit <NUM> illustrated in <FIG>.

As illustrated in <FIG>, the pressure detection unit <NUM> has a body <NUM>, a sensor unit <NUM>, a holding unit <NUM>, a urging unit <NUM>, a sensor board <NUM>, a zero-point adjusting switch <NUM> (see <FIG>), a mounting detection sensor (sensing unit) <NUM>, and a guide member (guide part) <NUM>.

As illustrated in <FIG>, the sensor unit <NUM> has a sensor body 12a, a housing member 12b, and a support member 12c. The sensor body 12a has the pressure detecting surface 12aA to which a distortion resistor is attached and a base part 12aB to which the pressure detecting surface 12aA is attached. The sensor body 12a is a distortion type sensor that outputs a pressure signal in accordance with a change in the resistance of a distortion resistor that deforms together with the pressure detecting surface 12aA in accordance with a transmitted pressure.

A through hole (not illustrated) that communicates with the pressure detecting surface 12aA is formed in the base part 12aB, and one of the surfaces of the pressure detecting surface 12aA is maintained at an atmospheric pressure. Thus, the sensor body 12a serves as a sensor that detects a gauge pressure based on the atmospheric pressure as a reference. The pressure detecting surface 12aA is formed in a thin film with an anti-corrosion material (for example, sapphire).

As illustrated in <FIG>, the housing member 12b extends along the axis Y and is formed in a cylindrical shape, which is a member to house the sensor body 12a therein. An internal thread 12bA is formed in the inner circumferential surface of the housing member 12b. The internal thread 12bA engages with an external thread 12cA formed on the outer circumferential surface of the support member 12c.

Two slits 12bB formed circumferentially in two portions and opened to the lower end are formed around the lower end of the housing member 12b. Each slit 12bB is inserted in a detent pin 14c that prevents the sensor unit <NUM> from rotating about the axis Y together with the mounting unit <NUM> when the operator rotates the mounting unit <NUM> about the axis Y.

As illustrated in <FIG>, the support member 12c extends along the axis Y and is formed in a cylindrical shape, which is a member to support the sensor body 12a inside the housing member 12b. The external thread 12cA is formed on the outer circumferential surface of the support member 12c. The sensor body 12a is fixed inside the housing member 12b by inserting the sensor body 12a in the housing member 12b and screwing and fastening the external thread 12cA of the support member 12c into the internal thread 12bA of the housing member 12b.

The holding unit <NUM> is a member extending along the axis Y and formed in a cylindrical shape, which is a member to hold the sensor unit <NUM> movably along the axis Y orthogonal to the pressure detecting surface 12aA. The holding unit <NUM> has a body 13a, a fixing member 13b, and an O-ring 13c. The O-ring 13c in contact with the outer circumferential surface of the housing member 12b of the sensor unit <NUM> is attached to the inner circumferential surface of the body 13a.

An external thread 13aA is formed in the outer circumferential surface of the lower end of the body 13a, and an internal thread 13bA is formed on the inner circumferential surface of the fixing member 13b. The body 13a is fixed to the guide member <NUM> mounted on the body <NUM> by screwing and fastening the internal thread 13bA of the fixing member 13b onto the external thread 13aA of the body 13a.

The urging unit (pushing unit) <NUM> generates urging force to urge the sensor unit <NUM> against the pressure transmitting surface 22a of the flow passage unit <NUM>. The urging unit <NUM> has a spring 14a, a base member 14b, and a detent pin 14c. The spring 14a is arranged with one end thereof being in contact with the base member 14b fixed to the body <NUM> and the other end being in contact with the support member 12c of the sensor unit <NUM>. The spring 14a generates urging force in accordance with the distance along the axis Y from one end, which is in contact with the base member 14b, to the other end.

The detent pin 14c is a member extending in a direction orthogonal to the axis Y and formed in a shaft and is fixed to the base member 14b. The detent pin 14c is inserted in the pair of slits 12bB formed in the lower end of the housing member 12b. The detent pin 14c prevents the sensor unit <NUM> from rotating about the axis Y together with the mounting unit <NUM> when the operator rotates the mounting unit <NUM> about the axis Y.

The sensor board <NUM> includes an amplifier circuit (not shown) that amplifies a pressure signal output from the sensor body 12a, an interface circuit that transmits the pressure signal amplified by the amplifier circuit to a pressure signal line (not shown) of the cable <NUM>, a power supply circuit (not shown) that transmits a power supply voltage supplied from outside via the cable <NUM> to the sensor body 12a, a zero-point adjustment circuit (not shown) that performs a zero-point adjustment when the zero-point adjustment switch <NUM> is pressed. The zero-point adjustment circuit performs an adjustment such that, at the time when the zero-point adjustment switch <NUM> is pressed, a pressure signal output from the sensor body 12a is set as a reference value (for example, zero).

As illustrated in <FIG> and <FIG>, the sensor unit <NUM> and the holding unit <NUM> of the pressure detection unit <NUM> protrude upward along the axis Y out of the body <NUM> with the pressure detecting surface 12aA being arranged at the top. As illustrated in <FIG> and <FIG>, the holding unit <NUM> has a pair of protrusions 13aB protruding in a direction orthogonal to the axis Y from the outer circumferential surface of the body 13a.

As illustrated in <FIG>, the protrusions 13aB formed on the outer circumferential surface of the holding unit <NUM> are formed in two portions spaced apart from each other by <NUM> degrees about the axis Y. As illustrated in <FIG>, when the flow passage unit <NUM> is not mounted on the pressure detection unit <NUM>, the pressure detecting surface 12aA of the sensor unit <NUM> is exposed to outside.

A mounting detection sensor <NUM> (see <FIG>) is a sensor that detects that the flow passage unit <NUM> has been mounted on the pressure detection unit <NUM>. The mounting detection sensor <NUM> detects that the circumferential positions about the axis of a recess 31aC of a groove 31a of the mounting unit <NUM> described later and the protrusion 13aB of the pressure detection unit <NUM> are matched.

Guide members <NUM> include grooves 18a that guide the flow passage <NUM> to a predetermined mounting position when the flow passage unit <NUM> is mounted on the pressure detection unit <NUM>. The guide members <NUM> are provided in pairs symmetrically on the axis Y1. The respective guide members <NUM> in pairs guide a part of the flow passage <NUM> on the side of the inflow port 21a and a part of the flow passage <NUM> on the side of the outflow port 21b to the predetermined mounting position.

Next, with reference to <FIG>, <FIG> and <FIG>, the flow passage unit <NUM> is described in detail.

As shown in <FIG>, the flow passage unit <NUM> includes a flow passage body 20A formed with the flow passage <NUM>, the recess <NUM>, and the opening <NUM>. The flow passage <NUM> allows fluid to flow therethrough in a flow direction extending along the axis X (first axis) from the inflow port 21a to the outflow port 21b. The recess <NUM> includes the pressure transmitting surface 22a arranged on the bottom thereof. The opening <NUM> opens in a direction along an axis Y orthogonal to the axis X.

The pressure transmitting surface 22a is a diaphragm formed in a thin film shape and formed of a material (for example, polycarbonate (PC)) having corrosion resistance. The pressure transmitting surface 22a is formed in a circular shape in a planar view and is centered at the axis Y. An outer peripheral edge of the pressure transmitting surface 22a is joined to the flow passage body 20A by bonding or welding so as to close the opening <NUM>. Consequently, fluid introduced to the flow passage <NUM> does not flow out of the flow passage <NUM>. Since the pressure transmitting surface 22a is formed in a thin film shape, the pressure transmitting surface 22a is displaced along the axis Y by pressure of fluid introduced into the flow passage <NUM>.

In a state shown in <FIG> where the flow passage unit <NUM> has been detached from the pressure detection unit <NUM>, the pressure transmitting surface 22a of the flow passage unit <NUM> is spaced apart from the pressure detecting surface 12aA of the pressure detection unit <NUM>. On the other hand, in a state shown in <FIG>, describe later, where the flow passage unit <NUM> has been mounted on the pressure detection unit <NUM>, the pressure transmitting surface 22a of the flow passage unit <NUM> is in contact with the pressure detecting surface 12aA of the pressure detection unit <NUM>. Thus, the pressure transmitting surface 22a transmits pressure of fluid flowing through the flow passage <NUM> to the pressure detecting surface 12aA.

In a state shown in <FIG> where the flow passage unit <NUM> is not mounted on the pressure detection unit <NUM>, the pressure transmitting surface 22a is exposed to the outside. Nevertheless, an operator has a less risk of touching the pressure transmitting surface 22a, since the pressure transmitting surface 22a is arranged on the bottom of the recess <NUM>.

As shown in <FIG>, on an outer peripheral surface of the recess <NUM> of the flow passage unit <NUM>, an endless annular groove 22b is formed to extend about the axis Y. On an inner peripheral surface of the mounting unit <NUM>, an endless annular protrusion 30a is formed to extend about the axis Y. The mounting unit <NUM> is formed of an elastically deformable material (for example, a resin material). When the mounting unit <NUM> is pressed toward the annular groove 22b formed on the outer peripheral surface of the recess <NUM>, the annular protrusion 30a is engaged with the annular groove 22b.

In a state shown in <FIG> where the annular protrusion 30a is engaged with the annular groove 22b, a minute gap is formed between an outer peripheral surface of the annular protrusion 30a and an inner peripheral surface of the annular groove 22b. Accordingly, the mounting unit <NUM>, which is mounted on the flow passage unit <NUM>, is rotatable about the axis Y relative to the sensor unit <NUM> and the holding unit <NUM>. This enables an operator to rotate the mounting unit <NUM> about the axis Y in a state where the pressure detection unit <NUM> is fixed to the installation surface S.

As illustrated in <FIG>, the mounting unit <NUM> is a member extending along the axis Y and formed in a cylindrical shape and has a connecting member <NUM> and a knob <NUM>. The mounting unit <NUM> is mounted on the flow passage unit <NUM> rotatably about the axis Y. As illustrated in <FIG> and <FIG>, the connecting member <NUM> has the groove 31a that accepts a protrusion 13aB protruding out of the body 13a of the holding unit <NUM>.

The groove 31a has a first groove 31aA extending along the axis Y and opened at the lower end and a second groove 31aB connected to the upper end of the first groove 31aA and extending circumferentially about the axis Y. The second groove 31aB has the recess 31aC formed in a shape corresponding to the outer circumferential surface of the protrusion 13aB at the other end on the circumferentially opposite side of one end connected to the first groove 31aA. The second groove 31aB is formed circumferentially in a range less than one turn about the axis Y from one end connected to the first groove 31aA to the other end in which the recess 31aC is formed. This range is desirably a range of <NUM>/<NUM> turns or less (a range of rotation angle of <NUM> degrees or less), for example.

A housing hole 31d used for housing the flow passage body 20A of the flow passage unit <NUM> is formed in the connecting member <NUM>. The housing hole 31d is formed circumferentially with a predetermined opening width so that the flow passage body 20A is rotatable about the axis Y with respect to the connecting member <NUM>. After the flow passage unit <NUM> is installed in the housing hole 31d of the connecting member <NUM>, the knob <NUM> is mounted on the upper end of the connecting member <NUM>, and thereby the flow passage unit <NUM> is housed in the housing hole 31d.

The knob <NUM> is a member that extends in the direction orthogonal to the axis Y and enables the operator to apply, in the direction along the axis Y, pressing force against urging force generated by the urging unit <NUM>. Further, the knob <NUM> is a member that enables the operator to apply force to rotate the mounting unit <NUM> circumferentially about the axis Y.

As illustrated in <FIG>, a pair of magnet holding parts 31b are formed in the connecting member <NUM> at positions on an extension line of the knob <NUM> extending straight. A magnet 31c is attached to each of the pair of magnet holding parts 31b.

Next, an operation to mount the flow passage unit <NUM> on the pressure detection unit <NUM> will be described.

The operator may work in the following procedure when mounting the flow passage unit <NUM> on the pressure detection unit <NUM> mounted on the installation surface S.

First, as illustrated in <FIG>, the center axis of the pressure detection unit <NUM> and the center axis of the flow passage unit <NUM> are matched to the axis Y, and the flow passage unit <NUM> is arranged such that the circumferential position about the axis Y of the protrusion 13aB of the pressure detection unit <NUM> and the circumferential position about the axis Y of the first groove 31aA of the mounting unit <NUM> are matched.

Next, the operator moves the flow passage unit <NUM> downward along the axis Y while maintaining the state illustrated in <FIG> and inserts the sensor unit <NUM> of the pressure detection unit <NUM> in the recess <NUM> of the flow passage unit <NUM>. Once the sensor unit <NUM> is inserted in the recess <NUM>, the pressure detecting surface 12aA of the sensor unit <NUM> is in contact with the pressure transmitting surface 22a of the flow passage unit <NUM>.

As illustrated in <FIG>, the protrusion 13aB of the pressure detection unit <NUM> has been inserted in the first groove 31aA of the mounting unit <NUM> with the pressure detecting surface 12aA being in contact with the pressure transmitting surface 22a. In a state where the operator does not apply pressing force to press the knob <NUM> downward, the urging unit <NUM> generates urging force to support the weight of the mounting unit <NUM> and the flow passage unit <NUM>.

Next, the operator applies pressing force to press the mounting unit <NUM> downward while gripping the knob <NUM> in the state illustrated in <FIG>. Once the downward pressing force is applied to the mounting unit <NUM>, the spring 14a of the urging unit <NUM> contracts, and the protrusion 13aB of the pressure detection unit <NUM> reaches the upper end of the first groove 31aA. The operator rotates the knob <NUM> clockwise circumferentially about the axis Y in a state where the protrusion 13aB has reached the upper end of the first groove 31aA and inserts the protrusion 13aB in the second groove 31aB into a state illustrated in <FIG>.

<FIG> is a front view illustrating the pressure detection device <NUM> during the mounting unit <NUM> being rotated from a release position to a lock position. <FIG> is a plan view of the pressure detection device <NUM> illustrated in <FIG>. <FIG> is a longitudinal sectional view of the pressure detection device <NUM> illustrated in <FIG>. As illustrated in <FIG>, in the pressure detection device <NUM> during the mounting unit <NUM> being rotated from the release position (the position illustrated in <FIG>) to the lock position, the knob <NUM> is arranged so as to extend in a direction orthogonal to both the axis X in which the flow passage body 20A extends and the axis Y.

As illustrated in <FIG>, in the pressure detection device <NUM> during the mounting unit <NUM> being rotated from the release position to the lock position, the mounting unit <NUM> mounts the flow passage unit <NUM> on the pressure detection unit <NUM> with the pressure detecting surface 12aA being in contact with the pressure transmitting surface 22a under the urging force generated by the urging unit <NUM>.

In the state illustrated in <FIG>, even if the operator reduces the force to press the knob <NUM> downward or releases the knob <NUM>, the mounting unit <NUM> to which upward urging force is applied by the urging unit <NUM> is restricted from moving upward in the direction of the axis Y. This is because the second groove 31aB comes into contact with the protrusion 13aB even if the mounting unit <NUM> is forced to move upward by the urging force of the urging unit <NUM>.

Next, the operator rotates the knob <NUM> clockwise circumferentially about the axis Y while gripping the knob <NUM> in the state illustrated in <FIG> and presses the recess 31aC arranged at the end of the second groove 31aB against the protrusion 13aB into a state illustrated in <FIG>. As illustrated in <FIG>, the recess 31aC is formed in a shape recessed downward along the axis Y from the second groove 31aB and corresponding to the outer circumferential surface of the protrusion 13aB.

<FIG> is a front view illustrating the pressure detection device <NUM> after the mounting unit <NUM> has been rotated to the lock position. <FIG> is a plan view of the pressure detection device <NUM> illustrated in <FIG>. <FIG> is a longitudinal sectional view of the pressure detection device <NUM> illustrated in <FIG>.

As illustrated in <FIG>, in a state where the mounting unit <NUM> has been rotated to the lock position, the recess 31aC of the second groove 31aB is pressed against the protrusion 13aB by the urging force generated by the urging unit <NUM>, and thereby the sensor unit <NUM> is positioned at a predetermined position on the axis Y.

Further, the mounting unit <NUM> is restricted from rotating about the axis Y when the recess 31aC is pressed against the protrusion 13aB by the urging force generated by the urging unit <NUM>. This is because, once the recess 31aC is pressed against the protrusion 13aB, unless the operator applies pressing force to press the knob <NUM> downward, the knob <NUM> is unable to be rotated anticlockwise.

In the above description, the operation to mount the flow passage unit <NUM> on the pressure detection unit <NUM> by rotating the mounting unit <NUM> from the release position to the lock position has been illustrated. An operation to remove the flow passage unit <NUM> from the pressure detection unit <NUM> will be an operation to rotate the mounting unit <NUM> from the lock position to the release position.

When removing the flow passage unit <NUM> from the pressure detection unit <NUM>, the operator presses the knob <NUM> downward to separate the recess 31aC from the protrusion 13aB and rotates the knob <NUM> anticlockwise into the state illustrated in <FIG>. The operator further rotates the knob <NUM> anticlockwise into the state illustrated in <FIG>. The operator then pulls the mounting unit <NUM> upward while dripping the knob <NUM> and thereby separates the flow passage unit <NUM> from the pressure detection unit <NUM>.

Next, the mounting detection sensor <NUM> that detects that the flow passage unit <NUM> has been mounted on the pressure detection unit <NUM> will be described with reference to <FIG> is a partial sectional view illustrating the pressure detection device <NUM> after the mounting unit <NUM> has been rotated to the lock position. As illustrated in <FIG>, the mounting detection sensor <NUM> is attached to the body <NUM> of the pressure detection unit <NUM>. The mounting detection sensor <NUM> is a lead switch, for example, which is a sensor that is switched on in response to detecting that a magnet is arranged at a proximate position.

As illustrated in <FIG>, when the circumferential positions about the axis Y of the recess 31aC and the protrusion 13aB are matched, the mounting detection sensor <NUM> is arranged at a proximate position of the magnet 31c. As illustrated in <FIG>, when the magnet 31c is held by each of the pair of the magnet holding parts 31b, the mounting detection sensor <NUM> can be arranged at any one of the positions at which the magnets 31c are arranged when the mounting unit <NUM> is in the lock position.

Although the flow passage unit <NUM> can be mounted on the pressure detection unit <NUM> with the inflow port 21a and the outflow port 21b being in the opposite direction, the mounting detection sensor <NUM> can detect that the magnet 31c comes in close proximity as long as the magnet 31c is held by each of the pair of the magnet holding parts 31b.

In another form, the magnet 31c may be held by either one of the pair of the magnet holding parts 31b, and a pair of mounting detection sensors <NUM> may be arranged at positions where the pair of the magnet holding parts 31b are arranged when the mounting unit <NUM> is in the lock position. In such a case, even when the inflow port 21a and the outflow port 21b are mounted on the pressure detection unit <NUM> in the opposite direction, any one of the pair of the mounting detection sensors <NUM> can detect that the magnet 31c is arranged at the proximate position.

In yet another form, the mounting detection sensor <NUM> may be attached to the mounting unit <NUM> in advance, and the magnet 31c may be attached to the pressure detection unit <NUM>. Even in such a case, the mounting detection sensor <NUM> can detect that the magnet 31c is arranged at the proximate position when the mounting unit <NUM> is in the lock position in the same manner as above.

The pressure detection device <NUM> according to this embodiment provides the following effects.

In the pressure detection device <NUM> according to this embodiment, the flow passage unit <NUM> is removably mounted on the pressure detection unit <NUM>. When fluid flowing through the flow passage <NUM> is changed, the used flow passage unit <NUM> can be removed from the pressure detection unit <NUM> to mount a new unused one on the pressure detection unit <NUM>. Consequently, there is no need to perform time-consuming cleaning of the flow passage <NUM> when fluid flowing through the flow passage <NUM> is changed, thereby enabling prompt work. Further, use of the new unused flow passage unit <NUM> can improve safety.

Further, according to the pressure detection device <NUM> of the present embodiment, the mounting unit <NUM> mounts the flow passage unit <NUM> on the pressure detection unit <NUM> with the pressure detecting surface 12aA being in contact with the pressure transmitting surface 22a under the urging force generated by the urging unit <NUM>. Since the pressure detecting surface 12aA is in contact with the pressure transmitting surface 22a under the urging force generated by the urging unit <NUM>, the strength of force with which the pressure detecting surface 12aA contacts the pressure transmitting surface 22a is always the same, and it is possible to prevent variation of the pressure detection characteristics obtained by the pressure detection unit <NUM>.

Further, according to the pressure detection device <NUM> of the present embodiment, when the operator holds the mounting unit <NUM> rotatably mounted on the flow passage unit <NUM> and presses the mounting unit <NUM> against the pressure detection unit <NUM> in a state where the circumferential positions of the first groove 31aA and the protrusion 13aB are matched, thereby the protrusion 13aB is inserted in the first groove 31aA. When the mounting unit <NUM> is pressed against the pressure detection unit <NUM>, the pressure detecting surface 12aA is in contact with the pressure transmitting surface 22a under the urging force generated by the urging unit <NUM>.

When the operator then rotates the mounting unit <NUM> within a range less than one turn about the axis Y, thereby the protrusion 13aB is inserted in the second groove 31aB connected to the first groove 31aA, and the sensor unit <NUM> is positioned at a predetermined position on the axis Y. The state where the pressure detecting surface 12aA is in contact with the pressure transmitting surface 22a under the urging force generated by the urging unit <NUM> is maintained with the sensor unit <NUM> being positioned.

The operator is able to mount the flow passage unit <NUM> on the pressure detection unit <NUM> by a relatively easy operation of pressing the mounting unit <NUM> against the pressure detection unit <NUM> and then rotating the mounting unit <NUM> within a range less than one turn about the axis Y. Further, it is possible to remove the flow passage unit <NUM> from the pressure detection unit <NUM> by a relatively easy operation of rotating the mounting unit <NUM> about the axis Y in the reverse direction. It is therefore possible to quickly mount and remove the flow passage unit on and from the pressure detection unit compared to a case where the operator rotates a nut about the axis for multiple times to mount and remove the flow passage unit on and from the pressure detection unit.

Further, according to the pressure detection device <NUM> of the present embodiment, when the operator rotates the mounting unit <NUM> about the axis Y to arrange the recess 31aC of the second groove 31aB at the position of the protrusion 13aB, thereby the recess 31aC is pressed against the protrusion 13aB by the urging force generated by the urging unit <NUM>. Since the recess 31aC is formed in a shape corresponding to the shape of the protrusion 13aB, once the recess 31aC is pressed against the protrusion 13aB, the mounting unit <NUM> is restricted from being rotated about the axis Y and is locked.

Thus, unless the operator presses and rotates the mounting unit <NUM> about the axis Y with pressing force against the urging force applied by the urging unit <NUM>, the flow passage unit <NUM> is not removed from the pressure detection unit <NUM>. It is thus possible to reliably maintain the state where the flow passage unit <NUM> is mounted on the pressure detection unit <NUM>.

Further, according to the pressure detection device <NUM> of the present embodiment, by using the mounting detection sensor <NUM> to detect that the circumferential positions about the axis Y of the recess 31aC and the protrusion 13aB are matched, it is possible to detect that the flow passage unit <NUM> is secured on the pressure detection unit <NUM>.

Further, according to the pressure detection device <NUM> of the present embodiment, when the circumferential positions about the axis Y of the recess 31aC and the protrusion 13aB are matched, the mounting detection sensor <NUM> attached to any one of the pressure detection unit <NUM> and the mounting unit <NUM> detects that the magnet 31c attached to the other of the pressure detection unit <NUM> and the mounting unit <NUM> is arranged at a proximate position. Accordingly, it is possible to reliably detect a state where the flow passage unit <NUM> is mounted on the pressure detection unit <NUM>.

Further, according to the pressure detection device <NUM> of the present embodiment, the operator is able to easily mount the flow passage unit <NUM> to the pressure detection unit <NUM> by applying pressing force via the knob <NUM> against the urging force generated by the urging unit <NUM> to the mounting unit <NUM>.

The guide member <NUM> provided to the pressure detection device <NUM> of the present embodiment described above is a member having a groove 18a used for guiding the flow passage <NUM> to a predetermined mounting position when mounting the flow passage unit <NUM> on the pressure detection unit <NUM>. As the shape of the guide member <NUM>, shapes illustrated in <FIG> may be employed.

<FIG> is a plan view illustrating a pressure detection device <NUM> of a modified example and illustrates a state where the flow passage unit <NUM> is in contact with the top of the guide member 18A. <FIG> is a left side view of the pressure detection device <NUM> illustrated in <FIG> and illustrates a state where the flow passage unit is in contact with the top of the guide member. <FIG> is a left side view of the pressure detection device <NUM> illustrated in <FIG> and illustrates a state where the flow passage unit has been accepted in the groove of the guide member.

As illustrated in <FIG>, the pressure detection device <NUM> is provided with a pair of guide members 18A at positions symmetrical about the axis Y on the axis Z crossing the axis Y and extending in the horizontal direction. Each of the guide members 18A is a member formed in an arc shape circumferentially about the axis Y. The guide member 18A has a groove 18Aa arranged on the axis Z and a pair of top parts 18Ab arranged adjacent to the groove 18Aa. As illustrated in <FIG>, each top part 18Ab is formed so as to extend circumferentially about the axis Y and within a range of an angle θ relative to the axis Z passing through the center of the groove 18Aa.

As illustrated in <FIG>, the groove 18Aa is formed so as to be recessed below the top part 18Ab along the axis Y and has a width W1 that can accept the flow passage body 20A of the flow passage unit <NUM>. The flow passage unit <NUM> is rotatable about the axis Y with respect to the mounting unit <NUM>, and the angle rotatable about the axis Y is θ illustrated in <FIG>.

When it is intended to mount the flow passage unit <NUM> on the pressure detection unit <NUM> in a state where the magnet holding part 31b is set to the release position, if the axis in which the flow passage body 20A extends is shifted by the angle θ relative to the axis Z as illustrated in <FIG>, the top part 18Ab of the guide member 18A comes into contact with the flow passage body 20A.

In such a case, it is not possible to move the flow passage unit <NUM> to come closer to the pressure detection unit <NUM>, and it is thus not possible to mount the flow passage unit <NUM> on the pressure detection unit <NUM>. As illustrated in <FIG>, in a state where the top part 18Ab of the guide member 18A is in contact with the flow passage body 20A, the flow passage body 20A is not accepted in the groove 18Aa. To mount the flow passage unit <NUM> on the pressure detection unit <NUM>, it is required to adjust the rotation angle about the axis Y of the flow passage unit <NUM> relative to the mounting unit <NUM> so that the axis X illustrated in <FIG> matches the axis Z.

If the rotation angle about the axis Y of the flow passage unit <NUM> relative to the mounting unit <NUM> is adjusted so that the axis X matches the axis Z, the position about the axis Y of the flow passage body 20A and the position about the axis Y of the groove 18Aa are matched on the axis Z. In this state, since the top part 18Ab of the guide member 18A does not come into contact with the flow passage body 20A, the flow passage body 20A is accepted in the groove 18Aa as illustrated in <FIG>, and this enables the flow passage unit <NUM> to be mounted on the pressure detection unit <NUM>.

As described above, according to the pressure detection device <NUM> of the modified example, when it is intended to mount the flow passage unit <NUM> on the pressure detection unit <NUM> in a state where the magnet holding part 31b is set to the release position, it is not possible to mount the flow passage unit <NUM> on the pressure detection unit <NUM> without matching the position about the axis Y of the flow passage body 20A and the position about the axis Y of the groove 18Aa to each other on the axis Z. It is therefore possible to suitably prevent the flow passage unit <NUM> from being erroneously connected to the pressure detection unit <NUM> in a state where the flow passage body 20A is not accepted in the groove 18Aa.

Claim 1:
A pressure detection device (<NUM>) comprising:
a pressure detection unit (<NUM>) configured to detect a pressure transmitted to a pressure detecting surface (12aA);
a flow passage unit (<NUM>) in which a flow passage (<NUM>) configured to cause a fluid to flow in a flow direction from an inflow port to an outflow port and a pressure transmitting surface (22a) used for transmitting, to the pressure detecting surface (12aA), a pressure of a fluid flowing through the flow passage (<NUM>) are formed; and
a mounting unit (<NUM>) used for removably mounting the flow passage unit (<NUM>) on the pressure detection unit (<NUM>),
wherein the pressure detection unit (<NUM>) includes
a body (<NUM>), a sensor unit (<NUM>) having the pressure detecting surface (12aA),
characterized in that the pressure detection device further comprises:
a holding unit (<NUM>) configured to hold the sensor unit (<NUM>) movably along an axis (Y) orthogonal to the pressure detecting surface (12aA), and
an urging unit (<NUM>) configured to generate urging force to urge the sensor unit (<NUM>) toward the pressure transmitting surface (22a), the urging unit (<NUM>) comprising a spring (14a) and a base member (14b),
wherein the spring (14a) is arranged with one end thereof being in contact with the base member (14b) fixed to the body (<NUM>) and the other end being in contact with a support member (12c) of the sensor unit (<NUM>),
wherein the spring (14a) is configured to generate the urging force in accordance with the distance along the axis (Y) from one end, which is in contact with the base member (14b), to the other end, and
wherein the mounting unit (<NUM>) mounts the flow passage unit (<NUM>) on the pressure detection unit (<NUM>) in a state where the pressure detecting surface (12aA) is in contact with the pressure transmitting surface (22a) under urging force generated by the urging unit (<NUM>).