JP2022176769A - Pressure detection device - Google Patents

Abstract

To provide a pressure detection device capable of easily and appropriately adjusting a gap (x) between a nozzle and a flapper for amplifying a detection pressure.SOLUTION: A pressure detection device includes a pressure detection chamber 5 and a comparison pressure chamber 6 partitioned by a flapper 2, a detection flow path 9 for connecting a pressure detection object A to the pressure detection chamber 5, a nozzle 21 for bringing its tip closer to the flapper 2 within the comparison pressure chamber 6, a fluid supply flow path 12 for supplying fluid to the nozzle 21, a discharge flow path 15 for discharging fluid passing through the nozzle 21, and an amplification pressure introduction chamber 7 within a casing 20. The nozzle 21 has a nozzle flow path 22 that allows a rear end 22b to be closed and has a fluid jet nozzle 22a and a supply port 22c, a nozzle holding hole 20d for holding the nozzle 21 so as to be capable of traveling axially in a state in which a rear end 21b of the nozzle 21 is exposed is formed on a first side face 20c of the casing 20, and an opposed clearance (x) between a tip 21a of the nozzle 21 and the flapper 2 is allowed to be adjustable by operating the rear end 21b.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pressure detection device that detects fluid pressure.

Conventionally, various devices have been devised to accurately detect minute pressure changes in fluids, minute differential pressures, and the like, but sensors capable of accurately detecting minute pressures are expensive. Therefore, as a device capable of substantially detecting a very small pressure using a relatively inexpensive sensor with low resolution by amplifying the very small pressure to be measured, for example, the device shown in FIG. 2 is available. Are known.

In the apparatus of FIG. 2, a first flapper 2, a partition wall 3, and a second flapper 4 are arranged in a housing 1 from the side of the bottom surface 1a. 6, the amplified pressure introduction chamber 7 and the reference pressure chamber 8 are divided, and the flow paths described below are formed outside these chambers 5 to 8 within the housing 1 .
A detection channel 9 is connected to the pressure detection chamber 5 , and the pressure detection target A, which undergoes minute pressure changes, is connected to the detection channel 9 .
The partition wall 3 that separates the comparison pressure chamber 6 and the amplified pressure introduction chamber 7 has a nozzle 10 whose tip is directed toward the first flapper 2 that separates the pressure detection chamber 5 and the comparison pressure chamber 6. installed. The nozzle 10 allows the comparison pressure chamber 6 and the amplification pressure introduction chamber 7 to communicate with each other. channel) 12 are connected.

Further, a switch member 13 made of iron is attached to the surface of the second flapper 4 facing the ceiling surface 1b of the housing 1, and the switch member 13 approaches the ceiling surface 1b of the housing 1 by a predetermined distance. A magnetic force switch 14 is provided which senses and turns on the magnetic force switch.
A discharge channel 15 is connected to the comparison pressure chamber 6, and an open channel 16 is connected to the reference pressure chamber 8, so that the pressure chambers 6 and 8 are open to the outside air.

In such an apparatus, when the pressure fluid is supplied from the supply channel 12, the fluid flows through the amplification pressure introduction chamber 7, the nozzle 10, the comparison pressure chamber 6 and the discharge channel 15 in order and is discharged to the atmosphere. In this device, when the pressure in the pressure detection chamber 5 is atmospheric pressure, the distance between the tip 10a of the nozzle 10 and the first flapper 2 is kept sufficiently large, and there is almost no difference between the front and rear of the nozzle 10. The pressure in the amplification pressure introduction chamber 7 and the pressure in the comparison pressure chamber 6 are made substantially equal in a state where pressure fluid is supplied from the supply passage 12 without generating pressure.

From this initial state, when the pressure of the pressure detection target A connected to the detection flow path 9 rises slightly, the pressure of the pressure detection chamber 5 rises, the first flapper 2 displaces toward the comparison pressure chamber 6 side, and the nozzle 10 The distance between the tip 10a of and the first flapper 2 is shortened. As a result, the fluid that passes through the nozzle 10 from the supply flow path 12 and is discharged to the comparison pressure chamber 6 is throttled, and the pressure in the amplified pressure introduction chamber 7 upstream of the nozzle 10 is increased.
At this time, the pressure in the amplified pressure introduction chamber 7 becomes higher than the pressure in the pressure detection chamber 5, that is, the minute pressure of the pressure detection target A due to the restriction formed by the tip 10a of the nozzle and the first flapper 2. , the positional relationship between the nozzle 10 and the first flapper 2, the rigidity of the first flapper 2, and the like are set.

That is, in this detection device, the first flapper 2 is made to easily bulge toward the comparison pressure chamber 6 by a minute pressure, and as a result, a constriction is formed between the tip 10a of the nozzle 10 and the first flapper 2. I'm trying
As a result, the minute pressure of the pressure detection object A can be amplified and the amplified pressure can be generated in the amplified pressure introduction chamber 7 . In this way, if the changed pressure of the pressure detection object A is amplified, even if the pressure change of the pressure detection object A is minute, the pressure change of the amplified pressure introduction chamber 7 becomes larger than that. The flapper 4 can be displaced. By displacing the switch member 13 provided on the second flapper 4, the magnetic force switch 14 can reliably detect the detected pressure.

In this way, a slight pressure change in the pressure detection chamber 5 is amplified by the restriction formed by the facing distance x between the tip 10 a of the nozzle 10 and the first flapper 2 . In the initial state where the pressure of the pressure detection target A is the atmospheric pressure, the facing distance x does not function as a throttle for the fluid supplied from the supply flow path 12, and the pressure in the pressure detection chamber 5 slightly increases. When it rises, it functions as a diaphragm, and it is necessary to set the size to exhibit a sufficient amplifying function.
Therefore, the nozzle 10 is attached to the partition wall 3 so that the distance x between the tip 10a and the first flapper 2 can be adjusted.

Japanese Patent Application Laid-Open No. 2003-300229

As described above, in order to amplify a slight change in pressure in the pressure detection chamber 5, it is necessary to appropriately set the facing distance x between the tip 10a of the nozzle 10 and the first flapper 2. FIG. There is also a device in which the nozzle 10 is attached to the partition wall 3 so that the position of the nozzle 10 can be adjusted in the axial direction in order to adjust the facing distance x. However, the nozzle 10 is attached to a partition wall 3 provided substantially in the center of the housing 1 as shown. Therefore, in order to adjust the position of the nozzle 10 with respect to the first flapper 2, the housing 1 had to be disassembled. Moreover, when the housing 1 is disassembled, the fluid cannot be supplied and the pressure cannot be detected.
Therefore, in order to appropriately adjust the position of the nozzle 10, the housing 1 is disassembled to change the nozzle position, and then the housing 1 is assembled so that minute pressure changes in the pressure detection target A can be detected appropriately. It is necessary to repeat the work of confirming whether or not there is a problem that the workability is very poor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressure detection device that facilitates proper adjustment of the facing distance x between the nozzle and the flapper.

A first invention comprises, in a housing, a flapper, a pressure detection chamber and a comparison pressure chamber partitioned by the flapper, a detection flow path connecting a pressure detection target to the pressure detection chamber, and the above pressure detection chamber in the comparison pressure chamber. A nozzle having a tip close to a flapper, a fluid supply channel that supplies fluid to the nozzle and the comparison pressure chamber, a discharge channel that is connected to the comparison pressure chamber and discharges the fluid that has passed through the nozzle, and the fluid an amplified pressure introduction chamber connected to a supply channel, and detecting pressure in the amplified pressure introduction chamber amplified by the flapper and the nozzle, wherein the nozzle has a fluid ejection port at its tip. a nozzle channel which is open and whose rear end is closed and which communicates with the comparison pressure chamber via the fluid ejection port; and a supply port which connects the nozzle channel to the fluid supply channel, The first side surface is formed with a holding hole for axially movably holding the nozzle with the rear end of the nozzle exposed to the outside of the housing. By manipulating it, the facing distance between the tip of the nozzle and the flapper can be adjusted.

In a second aspect of the invention, the detection channel and the fluid supply channel are opened on a side surface of the housing different from the first side surface where the rear end of the nozzle is exposed.

According to a third aspect of the present invention, in the housing, a side surface other than the first side surface is used as a mounting surface for mounting to a surface to be mounted.

According to a fourth aspect of the present invention, any side surface of the housing is used as a mounting surface, and when this mounting surface is mounted on the surface to be mounted, the pressure receiving surface of the flapper becomes a vertical surface.

According to the first invention, the position of the nozzle can be adjusted by operating the rear end of the nozzle. Therefore, the facing distance between the tip of the nozzle and the flapper can be adjusted and appropriately set without disassembling the housing.

According to the second invention, the pipes connected to the detection channel and the fluid supply channel are not connected to the side surface where the rear end of the nozzle is exposed. never become Therefore, it is particularly easy to adjust the gap between the nozzle and the flapper in a state in which the piping is attached and the fluid is flowing through the channel.

According to the third invention, the distance between the nozzle and the flapper can be adjusted after the housing is attached to the mounting surface and put into actual use.

According to the fourth invention, the flapper is not affected by gravity, and slight pressure displacement is reflected in the displacement of the flapper. Therefore, the detection accuracy of micro pressure is improved.

1 is a cross-sectional view of a pressure detection device according to an embodiment of the present invention; FIG. 1 is a cross-sectional view of a conventional pressure detection device; FIG.

[Embodiment]
Embodiments of the invention are described below. FIG. 1 is a cross-sectional view of this embodiment.
The pressure detection device of the embodiment shown in FIG. 1 is a device for detecting minute pressure changes in a pressure detection target A, like the conventional pressure detection device shown in FIG. 1, the same symbols as in FIG. 2 are used for components having the same functions as those of the conventional apparatus shown in FIG.

The pressure detection device of this embodiment shown in FIG. 1 is provided with components similar to those of the conventional device of FIG. However, the arrangement of the chambers 5 to 8 and the channels 9, 12, 15, 16 connected to them is different from that in FIG. Further, the configuration of the nozzle 21 projecting into the comparison pressure chamber 6 and having the tip 21a opposed to the first flapper 2 is different from that of the conventional nozzle 10 shown in FIG.
The following description focuses on the configuration different from the conventional device described above.

A pressure detection chamber 5 into which the pressure of the pressure detection target A is introduced and a comparison pressure chamber 6 are defined in the housing 20 via the first flapper 2 . A detection channel 9 is connected to the pressure detection chamber 5 , and a discharge channel 15 is connected to the comparison pressure chamber 6 . One end is open.
Further, in this embodiment, the first flapper 2 is arranged so that its pressure receiving surface is a vertical surface while the housing 20 is installed in another device or the like (not shown). For example, if the bottom surface of the housing 20 is the mounting surface 20b and the surface to be mounted is horizontal, when the mounting surface 20b of the housing 20 is mounted to the surface to be mounted, the pressure receiving surface of the first flapper 2 is substantially vertical. . For example, the mounting surface 20b side of the housing 20 is provided with a screw hole or the like for mounting to the mounting surface.

Further, a tip 21a of a rod-shaped nozzle 21 is opposed to the first flapper 2. The nozzle 21 extends into the comparison pressure chamber 6 from a first side surface 20c opposed to the second side surface 20a. It is attached to the nozzle holding hole 20d formed facing. The nozzle 21 has a nozzle flow path 22 inside on the tip 21a side. The nozzle flow path 22 has a fluid ejection port 22a opened at the tip 21a of the nozzle 21, and a rear end 22b thereof is closed. The nozzle 21 is formed with a supply port 22c near the rear end 22b of the nozzle channel 22 in the peripheral wall portion forming the nozzle channel 22. As shown in FIG. A fluid is supplied to the supply port 22c from the supply channel 12 that opens to the second side surface 20a. An annular groove 12b communicating with the nozzle holding hole 20d is formed at the end of the supply channel 12 on the nozzle 21 side. I am trying to communicate. An O-ring 23 for sealing between the annular groove 12b and the outer periphery of the nozzle 21 is attached to the annular groove 12b.

A male thread 21c is formed on the outer peripheral surface of the rear end side of the nozzle 21 so as to mesh with a female thread formed on the inner periphery of the nozzle holding hole 20d. The axial position of the nozzle 21 can be changed by threading the male screw 21c and the nozzle holding hole 20d, and the position of the tip 21a of the nozzle can be adjusted.
Further, a rear end surface 21b of the nozzle 21 exposed from the first side surface 20c of the housing 20 is formed with a tool insertion groove 21d for inserting a tool such as a wrench.

On the other hand, in this embodiment, the amplified pressure introduction chamber 7 and the reference pressure chamber 8 partitioned by the second flapper 4 are provided on the ceiling surface 20e side of the housing 20, as shown in FIG. 4 are placed almost horizontally.
An open flow path 16 is connected to the reference pressure chamber 8, one end of which is open on the second side surface 20a.

The amplified pressure introduction chamber 7 is connected to a branch passage 12a branching from the supply passage 12 between the throttle 11 of the supply passage 12 and the end of the supply passage 12 on the nozzle 21 side. The amplified pressure is introduced into the amplified pressure introduction chamber 7 via the supply channel 12 and the branch channel 12a.
A switch member 13 is attached to the second flapper 4, and a magnetic force switch 14 is attached to the ceiling surface 20e of the housing 20, as in the conventional case.
A throttle 11 is provided on the upstream side of the branch 12a in the supply flow path 12 to throttle the supply flow rate and increase the change in amplified pressure, making it easier to detect small pressure changes.

[Action, effect, etc.]
The operation of the pressure detection device of the embodiment configured as described above is the same as that of the conventional pressure detection device shown in FIG.
That is, when the pressure fluid is supplied from the supply channel 12, the fluid is supplied to the amplified pressure introduction chamber 7 via the branch channel 12a, and the supply channel 12, the annular groove 12b, and the nozzle channel 22 of the nozzle 21 (supply channel 22). The air flows in the order of the port 22c, the ejection port 22a), the comparison pressure chamber 6 and the discharge channel 15 and is discharged to the atmosphere.
When the pressure in the pressure detection chamber 5 is atmospheric pressure, the distance between the tip 21a of the nozzle 21 and the first flapper 2 is kept sufficiently large, and almost no differential pressure is generated across the nozzle 21. FIG. Therefore, in the initial state in which the pressure fluid is supplied to the supply passage 12, the pressure in the amplification pressure introduction chamber 7 and the pressure in the comparison pressure chamber 6 are substantially equal.

From this initial state, when the pressure of the pressure detection object A connected to the detection flow path 9 rises slightly, the pressure of the pressure detection chamber 5 also rises, the first flapper 2 displaces toward the comparison pressure chamber 6 side, and the nozzle 21 The facing distance x between the tip 21a of the first flapper 2 and the first flapper 2 is reduced. As a result, the fluid that passes through the nozzle 21 from the supply flow path 12 and is discharged to the comparison pressure chamber 6 is throttled, and the pressure in the amplified pressure introduction chamber 7 upstream of the nozzle 21 is increased.
At this time, the pressure in the amplified pressure introduction chamber 7 becomes higher than the pressure in the pressure detection chamber 5, that is, the minute pressure of the pressure detection target A due to the restriction formed by the tip 21a of the nozzle 21 and the first flapper 2. The positional relationship between the nozzle 21 and the first flapper 2 is set as shown.

In this way, it is possible to amplify the slightly increased pressure of the pressure detection object A and lead the amplified pressure to the amplified pressure introduction chamber 7 . In this way, if the changed pressure of the pressure detection object A is amplified, even if the pressure change of the pressure detection object A is minute, the pressure change in the amplified pressure introduction chamber 7 becomes large, and this pressure causes the second flapper 4 to move. can be displaced. Therefore, the magnetic force switch 14 can reliably detect the pressure.

In this way, a slight pressure change in the pressure detection chamber 5 is amplified by the restriction formed by the facing distance x between the tip 21 a of the nozzle 21 and the first flapper 2 .
Therefore, in the initial state where the pressure of the pressure detection target A is the atmospheric pressure, the facing distance x does not function as a throttle for the fluid supplied from the supply flow path 12, and the pressure in the pressure detection chamber 5 slightly increases. When it rises, it functions as a diaphragm and must be set to a size that exhibits a sufficient amplification function.

In this embodiment, since the rear end surface 21b of the nozzle 21 is exposed on the first side surface 20c of the housing 20, the operator inserts a tool into the tool insertion groove 21d formed in the rear end surface 21b. By rotating the nozzle 21, the position of the tip 21a can be adjusted and the facing distance x can be adjusted. At that time, the operator applies a known pressure to the pressure detection chamber 5, and while supplying pressure fluid from the supply channel 12, appropriately adjusts the facing distance x between the tip 21a and the first flapper 2. be able to.

As described above, since the rear end surface 21b of the nozzle 21 is exposed on the first side surface 20c of the housing 20, the position of the nozzle 21 can be adjusted without disassembling the housing 20. FIG. Therefore, it is easy to set an appropriate facing distance x while supplying fluid to the nozzles 21 .
In particular, since one end of each flow path 9, 12, 15, 16 is opened to the second side surface 20a facing the first side surface 20c, pipes or the like are connected to these flow paths 9, 12, 15, 16. Even when connected, the piping does not interfere with the position adjustment work of the nozzle 21.例文帳に追加
In this embodiment, the second side is a side different from the first side where the rear end of the nozzle 10 is exposed, and the openings of all the flow paths are provided on this second side. However, the opening of the flow path may be provided on any side surface of the housing 20 as long as it does not interfere with the work of adjusting the position of the nozzle 21 . The supply channel 12 and the detection channel 9 to which the pipes are connected may be provided on different sides. Also, like the discharge flow path 15 and the open flow path 16, if the openings are simply open to the atmosphere, they may be provided on the first side surface 20c.

Further, in this embodiment, when the mounting surface 20b of the housing 20 is mounted on a horizontal mounting surface, the pressure receiving surface of the first flapper 2 becomes a vertical surface, so the first flapper 2 is affected by gravity. It can be done easily.
When the pressure-receiving surface of the first flapper 2 is a horizontal surface, gravity acts perpendicularly to the pressure-receiving surface. Therefore, force in the downward bending direction always acts on the first flapper 2 . In this state, even if the pressure in the pressure detection chamber 5 changes slightly, the displacement of the first flapper 2 does not correspond to the pressure change in the pressure detection chamber 5, and a particularly small pressure change is detected. Sometimes I can't. However, if the influence of gravity on the first flapper 2 can be eliminated as in this embodiment, the pressure detection device can detect minute pressure changes with higher accuracy.

Since the amplified pressure acts on the second flapper 4, the influence of gravity on the amount of displacement is relatively small. Therefore, the pressure receiving surface of the second flapper 4 may be horizontal as shown. However, the pressure receiving surface of the second flapper 4 may be arranged vertically.
In this embodiment, the magnetic force switch 14 is turned on according to the displacement of the second flapper 4 when the pressure in the amplified pressure introduction chamber 7 reaches a predetermined value. Pressure can also be detected by other pressure sensing means. For example, the second flapper 4, the magnetic force switch 14, and the switch member 13 are not necessary if means for directly detecting the pressure in the amplified pressure introduction chamber 7 is provided.

Also, in the above description, a minute pressure change in the pressure detection chamber 5, which is slightly higher than the atmospheric pressure in the comparison pressure chamber 6, is detected. It can also be used to detect pressure.
For example, in order to detect the differential pressure between the pressure detection target A on the high pressure side and the detection target B on the low pressure side, the detection target B is connected to the comparison pressure chamber 6 via the discharge passage 15 in FIG. In this way, the first flapper 2 is inflated by the differential pressure between the pressure detection targets A and B, and the differential pressure is amplified. It can be detected by a detection means.

Furthermore, a tube is connected to the detection channel 9, the tip of the tube is inserted into the liquid in the container, and while a small amount of gas is supplied from the supply channel 12, the head pressure of the liquid is increased in the same manner as described above. can also be detected.
Further, a connecting plate (not shown) may be arranged on the side of the second side surface 20a of the housing 20 shown in FIG. 1, and a plurality of housings 20 may be connected by this connecting plate. A single connection passage communicating with the supply channel 12 of each housing 20 may be provided in the connection plate, and a supply source for supplying fluid to the supply channel 12 may be shared.

It can detect minute pressure changes and differential pressure.

2 First Flapper 5 Pressure Detection Chamber 6 Comparison Pressure Chamber 7 Amplified Pressure Introduction Chamber 9 Detection Channel 12 Supply Channel 15 Discharge Channel 20 Case 20a Second Side 20b Mounting Surface 20c First Side 20d Nozzle Holding Hole 21 Nozzle 21a Tip 21b Rear end face 22 Nozzle channel 22a Fluid ejection port 22b Rear end 22c (of nozzle channel) Supply port

Claims (4)

in the housing,
flapper and
A pressure detection chamber and a comparison pressure chamber partitioned by the flapper;
a detection channel that connects a pressure detection target to the pressure detection chamber;
a nozzle having a tip close to the flapper in the comparison pressure chamber;
a fluid supply channel that supplies fluid to the nozzle and the comparison pressure chamber;
a discharge channel connected to the comparison pressure chamber for discharging the fluid that has passed through the nozzle;
and an amplified pressure introduction chamber connected to the fluid supply channel,
A pressure detection device that detects the pressure in the amplified pressure introduction chamber amplified by the flapper and the nozzle,
The nozzle above
a nozzle flow path having a fluid jet opening at its tip end and a closed rear end communicating with the comparison pressure chamber through the fluid jet outlet;
a supply port for connecting the nozzle channel to the fluid supply channel;
On the first side of the housing,
A nozzle holding hole is formed to hold the nozzle movably in the axial direction with the rear end of the nozzle exposed to the outside of the housing,
A pressure detection device in which a facing distance between the tip of the nozzle and the flapper can be adjusted by manipulating the exposed rear end of the nozzle. 2. The pressure detection device according to claim 1, wherein the detection channel and the fluid supply channel are opened on a side surface of the housing different from the first side surface where the rear end of the nozzle is exposed. 3. The pressure detecting device according to claim 1, wherein a side surface of the housing other than the first side surface serves as a mounting surface for mounting to a surface to be mounted. 3. The pressure detecting device according to claim 1, wherein the pressure receiving surface of the flapper is a vertical surface when one of the side surfaces of the housing is used as a mounting surface and this mounting surface is mounted on the surface to be mounted.

Images