JPH0610623B2 - Flow rate detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flow rate detector capable of instantaneously detecting the mass flow rate of a fluid.

<Prior Art> Conventionally, as a flow rate detector for detecting the flow rate of a fluid,
There is something like the one shown in FIG. 3 (US Pat. No. 3,953).
3,819). This flow rate detector 100 has a flange 1
01, housings 102, vanes 103, rotating shaft 10
5. The potentiometer 106 and the torsion spring 107 make up a schematic structure. One end of the vane 103 is fixed to the rotating shaft 105, and the torsion spring 1
It is mounted so as to rotate against the spring force of 07, and the rotary shaft 105 is fixed to the slider of the potentiometer 106. Therefore, the vane 1
An electric signal can be taken out from the lead wire 108 according to the rotation angle of 03. As shown in FIG. 3, the flow rate detector 100 has a flow passage 109 so that the rotation axis 105 of the vane 103 is perpendicular to the axis of the fluid flow passage 109.
, The central portion of the free tip of the vane 103 is located at the axial position of the flow passage 109, and the flow passage 10 is inserted into the flow passage 109.
It is installed so as to face a wall 111 provided at right angles to the axis of 9, and the flange 101 is fixed to the main body 110 with a bolt.

The fluid flowing through the flow path 109 rotates the vanes 103 at an angle according to the flow velocity. Therefore, the flow rate detector 100 can detect the volume flow rate as a function of the rotation angle of the vane 103.

<Problems to be Solved by the Invention> However, in the above conventional flow rate detector, the passage resistance when passing through the vane 103 is detected by the pressure difference between the fluids on both sides of the vane 103 (the rotation angle of the vane 103). Therefore, the detected flow rate is the volume flow rate, and the mass flow rate cannot be detected. Therefore, there is a problem that it is impossible to accurately detect a flow rate such as a flow in which cavitation occurs or a flow including bubbles. Further, since the passage resistance of the fluid is affected by the viscosity change due to the temperature change, there is a problem that the flow rate cannot be accurately detected in an environment where the temperature is unstable.

Therefore, an object of the present invention is to detect a change in the momentum (momentum) of a fluid and obtain a mass flow rate so that it is not affected by a temperature change, and a flow in which cavitation occurs, a flow including bubbles, etc. An object of the present invention is to provide a flow rate detector capable of accurately detecting the mass flow rate of

<Means for Solving the Problems> In order to achieve the above object, the flow rate detector of the present invention comprises:
As illustrated in FIG. 1, a main body having a cylindrical chamber 3a inside and a body slidably fitted in the chamber 3a so that fluid flows from the outside into the internal passages 11a, 11 and is again outside. And the detection body 5 provided in the main body.
Inflow passages 17, 17 for guiding fluid to the internal passages 11a, 11 in the detection body 5 at an angle inclined with respect to the axis of
... and the internal passage 11a, which is provided in the detection body 5,
The inflow passages 17, 17, ...
Has the outflow passages 13, 13, ... Introduced into the main body at an angle inclined in the same inclination direction as the inflow passages 17, 17 ,.
... through the inside of the detection body 5 and the outflow passage 1
The momentum detection unit 1 that acts on the detection body 5 in the axial direction by the change in the momentum of the mass of the fluid flowing out through the plurality of inlet ports 3.
2, 33, and a spool 38 that is switched and connected. The spool 38 and the detection body 5 are coaxially integrally coupled to each other to form an operating member 43. The operating member 43 faces the one end 14a of the operating member 43. While forming the pressure chamber 48, the operating member 43
Forming a second pressure chamber 40 facing the other end 39a of the first pressure chamber 4 and the passage connected to the inflow passages 17, 17 ... Or the outflow passages 13, 13 ,.
8 is connected by a first control line having a throttle 66, while the passage and the second pressure chamber 40 are connected by a second control line having a throttle 69, and the downstream side of the throttle 66 in the first control line is connected. One side is connected to any one of the inlet ports, while the downstream side of the throttle 69 in the second control line is connected to another inlet port, and the outflow body is connected through the inflow passages 17, 17 ,. The first pressure chamber 48 and the second pressure chamber 48 which are in equilibrium with the axial force acting on the detection body 5 due to the change in the momentum of the mass of the fluid flowing in through the outflow passages 13, 13 ,. It is characterized in that a pressure measuring means for detecting a pressure difference with the pressure chamber 40 as mass flow rate information of the fluid flowing in the detection body 5 is provided.

The principle of the present invention will be described below.

The equation of the momentum of the fluid in an arbitrary inspection plane can be expressed as [external force] = [flow rate in mass] × [speed change]. That is, for example, an inflow angle of a fluid flowing into an arbitrary inspection surface in a certain direction is θ ₁ , an outflow angle of a fluid flowing out of the inspection surface in the certain direction is θ ₂ , and an inflow velocity of the fluid to the inspection surface is V 2. _1. Let V _{2 be} the outflow velocity of the fluid from the inspection surface and Q be the flow rate of the fluid flowing into and out of the inspection surface, and the equation of the momentum in a certain direction of the inspection surface can be expressed as follows. it can.

F = ρ · Q (V ₂ COSθ ₂ −V ₁ COSθ ₁ ) + ρ · L · + Fτ + α (1) Where, ρ: Density of fluid L: Damping length (fluid inlet and outlet of inspection surface) The above-mentioned constant direction component of the distance between) and: dQ / dt F τ: Viscous frictional force generated between the fluid and the inner wall of the portion where the fluid passes through the inspection surface α: The object surrounded by the inspection surface is the fluid It is an excessive force required to accelerate the entire object when moving by the force received from.

Usually, the term of ρ · L · + Fτ + α in equation (1) is ρ
Since Q (V ₂ COSθ ₂ −V ₁ COSθ ₁ ) is a sufficiently small amount compared to the term, it can be ignored and the above equation (1) is as follows.

F = ρ · Q (V ₂ COSθ ₂ -V ₁ COSθ ₁ ) ... (2) Here, the cross-sectional area of the inlet of the inflow passage for guiding the fluid to the detection body is A ₁ , and the fluid from the detection body is Assuming that the cross-sectional area of the outlet of the outflow passage provided in the detection body for outflow is A ₂ , the equation (2) is assumed to be V ₁ = Q / A ₁ and V ₂ = Q / A ₂ , Becomes Therefore, the mass flow rate (ρ · Q) can be expressed as a function of the axial force of the detector with θ, A and ρ as constants.
If this force F is detected by an appropriate means, the mass flow rate can be detected.

<Operation> The fluid supplied to the main body of the momentum detection unit 1 is guided into the internal passages 11a, 11 of the detection body 5 at an inclined angle by the inflow passages 17, 17, ... Provided in the main body. Further, the outflow passages 13, 13, ... Are guided into the main body at an angle inclined in the same inclination direction as the inflow passages 17, 17 ,. At this time, a force acts on the detection body 5 due to a change in the momentum of the mass of the fluid, and the spool 38 integrally coupled to the detection body 5 coaxially is moved. That is, the operating member 43 is moved. Then, the space between one of the plurality of inlet ports 32 and 33 and the outlet port 35 is opened, and the throttle 66 of the first control line or the second
The fluid supplied to the inlet port via the control line throttle 69 is discharged from the outlet port 35 to the outside.
As a result, a differential pressure is generated between the two pressure chambers 40 and 48.
Then, the operating member 43 stops at a position where the pressure difference and the force acting on the detection body 5 due to the change in the momentum are balanced.

By detecting the differential pressure thus generated by the pressure measuring means, the fluid flowing into the detection body 5 through the inflow passages 17, 17, ... And flowing out through the outflow passages 13, 13 ,. The change in mass momentum is measured to determine the mass flow rate. Therefore, the flow rate can be measured without being affected by the temperature, and the mass flow rate such as a flow including bubbles can be detected.

<Example> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

FIG. 1 is a cross-sectional view of a flow rate detector (hereinafter, referred to as a momentum flow rate detector) that is roughly configured by the momentum detection unit 1 and the control valve 31.

The moment detecting unit 1 has a cylindrical shaft hole 2a in the axial direction.
The main body 2 has a sleeve 3, the sleeve 3 is fitted in the shaft hole 2a, and the cylindrical detector 5 is slidably fitted in the hole 3a of the sleeve 3.

The detection body 5 is a portion that takes out a change in the momentum of the fluid as a force. A hole 5a is opened from the left end surface 5b of the detection body 5 in the figure along the axis of the detection body 5, and a screw portion 10 is provided near the entrance of the hole 5a. The threaded portion 14a of the plug 14 is screwed into the threaded portion 10 to seal the hole 5a.
A chamber 15 is formed therein. In addition, the outer peripheral surface 5 of the detection body 5
From e, four holes 11, which are spaced 90 ° apart from each other and penetrate through the hole 5a toward the axis of the detection body 5,
11 are provided on the outer peripheral surface 5e of the detection body 5, and even if the detection body moves in the hole 3a of the sleeve 3, all the inflowing fluid can be guided to the holes 11, 11 ,. An annular groove 11a having a width is provided. The annular groove 11a and the hole 11 form an internal passage on the inflow side of the detection body 5. Further, at intervals of 45 ° from the outer peripheral surface 5e, an angle θ is formed toward the axis of the detection body 5, and the hole 5a of the detection body 5 is located on the left end surface 5b side of the through hole of the hole 11. Eight outflow passages 13, 13, ... Penetrating therethrough are provided.

The outer peripheral surface 3b of the sleeve 3 penetrates through the hole 3a at intervals of 90 ° with respect to the axis of the detection body 5 at the same angle θ as the outflow passages 13, 13 ,. , Are provided, and the cross-sectional area of these inflow passages 17, 17 ,.
Make the same as the cross-sectional area of. Further, the outer peripheral surface 3b is spaced at an angle of 45 ° from each other, and eight holes 18 penetrating into the hole 3a on the left end surface 3c side of the through hole of the inflow passage 17 toward the axis of the detection body 5. , 18 are provided in the inner peripheral surface 3a of the sleeve 3 so that even if the detection body 5 moves, all the fluid flowing out from the outflow passages 13, 13 ,.
An annular groove 18a having a width sufficient to guide to 18
To provide.

The inflow passage 1 of the sleeve 3 is formed on the lower surface 2b of the main body 2 in the figure.
An inflow port 19 that is in constant communication with 7, 17, ... Is opened. Further, the holes 18, 1 of the sleeve 3 are provided on the upper surface of the main body 2 in the figure.
Open an outlet 21 that is in constant communication with 8, ... further,
The inner peripheral surface 2a of the main body 2 is provided with an annular groove 20 which is in constant communication with the inflow passages 17, 17, ...
I try to run into 7, ... Similarly, an annular groove 24 that allows the holes 18, 18, ... Of the sleeve 3 to communicate with the outflow port 21 at all times is similarly provided, and all the outflow passages 1 are provided.
The fluid flowing out from the nozzles 3, 13, ... Is discharged from the outlet 21 to the outside.

The control valve 31 communicates with the first inlet port 32, the second inlet port 33, and the outlet port 35 in the center, and
A housing 37 having a cylindrical valve chamber 36, one of which is open, is provided in the valve chamber 36 between the outlet port 35 and the first inlet port 32 and between the outlet port 35 and the second inlet port 33. A spool 38 that opens and closes with a land 38a is slidably fitted. Further, the end surface 39a of the land 39 provided at one end of the spool 38 is
A second pressure chamber 40 is formed by and the wall surface of the housing 37. On the other hand, the other end of the spool 38 is coaxially fixed to the cylindrical portion 5d protruding from the end surface 5c of the detection body 5,
The plug 14, the detector 5, and the spool 38 form an integral operating member 43. At the same time, the housing 37
Fits the protrusion 37b provided on the end surface 37a on the side where the valve chamber 36 is open to the inner hole 3a of the sleeve 3, and the opening of the valve chamber 36 provided on the protrusion 37b has the above-mentioned opening. The cylindrical portion 5d of the detector 5 is fitted and fixed to the main body 2 with a bolt or the like (not shown).

Further, in the cover 51 at the left end in the figure, the cylindrical protrusion 51b provided on the end face 51a is fitted into the inner hole 3a of the sleeve 3, and the above-mentioned detection is made in the hole 53 provided at the axial center of the protrusion 51b. The plug 14 fixed to the body 5 is slidably fitted and fixed to the main body 2 with a bolt or the like not shown, and the end surface 14a of the plug 14 and the wall surface of the cover 51 form a first pressure chamber 48. .

The first spring 54 is contracted between the end surface of the protruding portion 51b of the cover 51 and the left end surface 5b of the detection body 5, while the end surface of the protrusion 37b of the housing 37 and the detection body 5 are arranged.
The second spring 55 is contracted between the right end surface 5c and the right end surface 5c, and the detection body 5 is positioned at the neutral position by the urging force of the first spring 54 and the second spring 55 when the momentum detection unit 1 is not operating. The positions of the openings of the upstream inflow passages 17, 17, ... Are aligned with the positions of the holes 11, 11 ,.

Further, the sleeve 3 is provided with holes 44, 45 communicating with the right chamber 41 formed by the cylindrical portion 5d of the detection body 5, the detection body 5, the sleeve 3, and the housing 37.
An annular groove 44a communicating with the outer peripheral surface 3b of the sleeve 3 is provided. Further, holes 46 and 47 communicating with the left chamber 42 formed by the sleeve 3, the detection body 5, the sleeve 3, the cover 51, and the plug 14 are provided, and an annular groove 46a communicating with the holes 46 and 47 is provided on the outer circumference of the sleeve 3. It is provided on the surface 3b. Further, the main body 2 is provided with a communication hole 49 communicating with the annular groove 44a and a communication hole 50 communicating with the annular groove 46a.

The momentum flow rate detector and the pressure source 61 are connected as follows. The pressure source 61 and the inflow port 19 of the momentum detector 1 are connected via a passage 62, and the passage 63 is connected to the outflow port 21. The branch point 65 provided in the passage 62 and the first pressure chamber 48 are connected via a first control line 67 having a first throttle 66, and the branch point 65 is provided.
The second pressure chamber 40 and the second pressure chamber 40,
Connect via control line 70. Further, the downstream side of the first throttle of the first control line 67 is connected to the first inlet port 32 of the control valve 31 via the line 73, and the second port
The downstream side of the second throttle 69 of the control line 70 is connected to the second inlet port 33 via the line 74, and the outlet port 35 is connected to the tank 75. Here, the diaphragm 6
6, 69 may be provided on either one of the first control line 67 and the second control line 70.

Further, the communication hole 49 provided in the main body 2 is narrowed by the diaphragm 76.
And the communication hole 50 is connected to the passage 63 via a line 79. Therefore, the chamber 41 of the momentum detector 1
The drain generated in 42 is the holes 44, 45, 46, 4
7, the annular grooves 44a and 46a, the communication holes 49 and 50, and the lines 78 and 79 to flow into the passage 63. Communication hole 4
The lines 78, 79 connected to 9, 50 may be connected to the passage 62.

The momentum flow rate detector having the above structure converts the change in the momentum of the fluid into a force by the detection body 5, and drives the spool 38 of the control valve 31 by the force to operate the operating member 43.
Pressure P ₁ , P of the fluid acting on both end faces 41a, 39a of the
₂ to control the change of the momentum of the fluid by the pressures P ₁ and P ₂
It is detected as a differential pressure of, and operates as follows.

The fluid supplied from the pressure source 61 and flowing in from the inflow port 19 through the passage 62 is the annular groove 20 provided in the main body 2.
Four inflow passages 17, 17, ... Provided in the sleeve 3, an annular groove 11a provided in the detection body 5 and four holes 11, 1
1, and flows into the chamber 15 of the detection body 5. Further, the fluid flowing into the chamber 15 is transferred to the eight outflow passages 13, 13, ... Provided in the detection body 5, the annular groove 18a provided in the sleeve 3, the eight holes 18, 18 ,. It passes through the provided annular groove 24 and flows out from the outlet 21.

At this time, the closed curved surface surrounded by the outer peripheral surface 5e of the detection body 5 and both end surfaces 5b and 5c of the detection body 5 can be considered as an inspection surface. Therefore, the inflow passage 17,
Inflow from 17, ... at a constant angle to the axis of the detection body 5,
The change in the momentum of the fluid flowing out at a constant angle from the outflow passages 13, 13 provided in the inspection surface depends on the force acting on the object (in this case, the detection body 5) in the inspection surface. Equally, the above equation (3) is obtained. As described above, in this embodiment, the angle θ ₁ of the inflow passages 17, 17, ... Is equal to the angle θ ₂ of the outflow passages 13, 13 ,. Since A ₁ and the cross-sectional area A _{2 of the} outlet are set to be equal (= A), they flow into the inspection surface including the outer peripheral surface 5e as shown in the equation (4), and further within the inspection surface. The mass flow rate of the fluid flowing out further is
It can be detected by detecting the force acting on. Here, the outer peripheral surface of the detection body 5 forming the inspection surface is a cylindrical surface (inner circumference of the sleeve 3) including the surfaces 5e, 5e, ... In contact with the inner peripheral surface 3a of the sleeve 3 in the detection body 5. Corresponding to the surface 3a).

In addition, as described above, the detection body 5 has the first spring 54
And the second spring 55, the center of the opening of the inflow passages 17, 17, ...
It is supported so that its center coincides with that of a. Therefore,
The detection body 5 is displaced against the spring force of the first spring 54 or the second spring 55 according to the force received by the flow of the fluid. When the detector 5 is displaced, the plug 14 of the actuating member 43, the detector 5, and the spool 38 move together in the hole 53, the inner hole 3a of the sleeve 3, and the valve chamber 36.

Further, the pressure source 61 flowing through the first control line 67.
A part of the fluid supplied from is supplied to the first pressure chamber 48 from the first control line 67 having the throttle 66, and
It is supplied to the first inlet port 32 via a line 73. Further, the pressure source 6 flowing through the second control line 70
Part of the fluid supplied from 1 is supplied to the second pressure chamber 40 from the second control line 70 having the throttle 69, and
It is supplied to the second inlet port 33 via the line 74. That is, since the first control line 67 and the second control line 70 are connected to the same branch point 65 of the passage 62, the same pressure P is applied to the first pressure chamber 48 and the second pressure chamber 40, respectively. It is working.

Next, as described above, the force F is applied to the detection body 5 of the operating member 43.
When, for example, the actuating member 43 is displaced to the right side in the drawing by the action of, the land 38a of the spool 38 starts to open between the first inlet port 32 and the outlet port, and is supplied through the line 73. The fluid is discharged to the tank 75. Then, the fluid pressure in the line 73, that is, the pressure of the fluid supplied to the first pressure chamber 48 starts to drop to P ₁ due to the resistance of the throttle 66, and the both end surfaces of the actuating member 43, that is, the end surface 14 a of the plug 14 and the land 39. the pressure difference _P 2 -P ₁ the pressure _P 1, _{P 2} of the fluid acting on the end face 39a of the occurs, the actuating member 43 by the pressure difference _P 2 -P ₁ is urged to the left in FIG. The operating member 43 has the pressure difference P
The force F acting on the spring force and the detection of the biasing force and the spring by ₂ -P ₁ are balanced to stop at the position. At this time, the balance formula of the force acting on the actuating member 43 is as follows.

_{F = Ap (P 2 -P 1} ) + Fs ...... (5) where, Ap: plug 14 and the pressure receiving area P ₁ of the land 39: pressure P ₂ acting on the end face 14a of the plug 14 at the time of balance: balance Pressure Fs acting on the end face 39a of the land 39 during the time: Spring force of the spring during balancing The width of the land 38a of the spool 38 is substantially equal to the circumferential groove of the valve chamber 36 communicating with the outlet port 35 (that is, 0). Since the lap is set, the control valve 31 can perform a control operation with respect to a slight displacement of the actuating member 43, and has very good responsiveness. As described above, since the displacement amount of the spring is very small, the spring force Fs can be ignored, and the following equation is obtained from the above equations (4) and (5), The mass flow rate (ρ · Q) of the fluid supplied from the pressure source 61 is proportional to the pressure difference (P ₂ −P ₁ ). Therefore, the detection unit Pc
_Using the pressures P ₁ and P ₂ acting on both end faces of the actuating member 43, which are detected by ₁ and Pc ₂ , the mass flow rate is changed to the differential pressure P ₂
It can be detected as P ₁ . In addition, the differential pressure P ₂ −
It is possible to control other fluid equipment (not shown) according to the mass flow rate of the fluid supplied from the pressure source 61 by using P ₁ .

In the above-mentioned embodiment, the annular groove 11a, the hole 11,
A flow path including the chamber 15 and the outflow passage 13 is provided. However, since the present invention can be obtained by allowing the fluid to flow into the inspection surface including the outer peripheral surface 5e of the detection body 5 at a constant angle and further to flow out from the inspection surface at a constant angle, the flow does not necessarily flow into the detection body 5. It is not necessary to form a path, and the detection body 5 may have any shape as long as it can convert the momentum of the fluid into a force.

Further, a sleeve 3 is interposed between the detection body 5 and the main body 2, and the sleeve is provided with flow passages 17, 17, ..., An annular groove 18a for letting out a fluid, a hole 18 and the like. However, the present invention is not limited to this,
The inflow passages 17, 1 can be directly introduced into the main body 2 without using the sleeve 3.
.., annular groove 18a, etc. may be provided.

In each of the above-described embodiments, the inflow angle θ ₁ into the inspection surface including the outer peripheral surface 5e of the detection body 5 and the outflow angle θ ₂ from the inspection surface, or the cross-sectional area A _{1 of the} inflow port. And the cross-sectional area A _{2 of the} outflow port have the same value,
The present invention is not limited to this.

Further, the fluids supplied by the first control line 67 and the second control line 70 may be supplied from anywhere as long as the reference pressures are the same, and thus the branch point 65 may be provided in the passage 63. Good.

Thus, the change of the momentum of the fluid is converted into a force by the detection body 5 of the operating member 43, and this force is further converted into the displacement of the spool 38 of the operating member 43, which acts on both end surfaces of the operating member 43. Controlling the pressure of the fluid to convert the displacement into a differential pressure of the fluid acting on both end surfaces of the operating member 43,
By detecting this pressure difference, it is possible to detect the change in the momentum of the fluid, so it is possible to detect the mass flow rate that is not affected by the viscosity change due to the temperature change of the fluid, and the flow and bubbles that cause cavitation. It is also possible to detect the flow rate such as a flow including the flow rate. Further, since the spool 38 is a zero lap, a slight movement of the spool can generate a pressure difference to counteract the axial thrust, and therefore the response is good and the mass flow rate can be instantaneously achieved. Can be detected. And spool 3
No. 8 is constantly moving according to the fluctuation of the flow rate of the fluid, and in addition, since a large pressure difference does not occur except for the portion through which the fluid supplied from the lines 73 and 74 passes, even if it is used for a long time, High reliability can be obtained without lick lock or silting.

The land 38a of the spool 38 is set to the zero-wrap state, but the present invention is not limited to this, and may be overlap or underlap.

Further, the pressure difference P ₂ −P ₁ can be increased by reducing the pressure receiving areas Ap of the both end surfaces 14 a, 39 a of the actuating member 43 and reducing the throttles 66, 69. It can be detected well.

Furthermore, since the momentum detector 1 and the control valve 31 are integrated and compact, the momentum detector 1 and the control valve 31 can be incorporated into another fluid device to control the other fluid device with the differential pressure.

<Effects of the Invention> As is clear from the above, the flow rate detector of the present invention has a structure in which the flow rate detector of the main body having the cylindrical chamber therein is inclined at an angle inclined with respect to the axis through the inflow passage of the main body. A force acts on the detection body due to a change in the momentum of the mass of the fluid flowing into the internal passage and flowing out through the outflow passage at an angle inclined in the same inclination direction as the inflow passage, and this force is integrated with the detection body. The outlet port is switched and connected to one of the plurality of inlet ports by the coupled spool, and the fluid supplied to the inlet port via the first line or the second line is discharged to the outside from the outlet port, and the detection is performed. A pressure difference is generated in the first pressure chamber and the second pressure chamber formed at both ends of the operating member composed of the body and the spool, and this pressure difference is detected by the pressure measuring means, so that the change in the momentum of the mass of the fluid is detected. The above operation It can be detected as the difference in pressure acting on both ends of the member, and the mass flow rate of the fluid can be obtained.

Therefore, it is possible to accurately detect the mass flow rate of a fluid that causes cavitation, a fluid including bubbles, or the like, without being affected by a change in viscosity of the fluid due to a change in temperature.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the flow rate detector of the present invention, FIG. 2 is a perspective view of a conventional flow rate detector, and FIG. 3 is a view showing a state in which the conventional flow rate detector is installed in a flow path. 2 is a sectional view taken along the line AA of FIG. 1 ... Momentum detection part, 2 ... main body, 3 ... sleeve, 5 ... detector, 13 ... outflow passage, 17 ... inflow passage, 32 ... first inlet port, 33 ... second inlet port , 35 ... Outlet port, 38 ... Spool, 40 ... Second pressure chamber, 43 ... Operating member, 48 ... First pressure chamber, 66 ... First throttle, 67 ... First control line, 69 ...... Second diaphragm, 70 ...... Second control line.

Claims (1)

[Claims] 1. A body having a cylindrical chamber (3a) inside, and a body slidably fitted in the chamber (3a) so that fluid flows from the outside into the internal passages (11a, 11). Detecting body flowing out again (5)
And the internal passage in the detection body (5) provided at an angle oblique to the axis of the detection body (5) provided in the main body.
The inflow passages (17, 17, ...) for guiding the fluid to the (11a, 11) and the inflow passages provided in the detection body (5) for the fluid in the internal passages (11a, 11) with respect to the shaft. (17,17, ...) has an outflow passage (13,13, ...) which is guided into the main body at an angle inclined in the same inclination direction, and the detection is performed through the inflow passage (17,17, ...). A momentum detection unit (a) for exerting an axial force on the detection body (5) by a change in the momentum of the mass of the fluid flowing into the body (5) and flowing out through the outflow passages (13, 13, ...). 1) and a spool (38) for switching and connecting the outlet port (35) to a plurality of inlet ports (32, 33), and the spool (38) and the detection body (5) are coaxially integrally coupled. To constitute the operating member (43), and facing the one end (14a) of the operating member (43), the first pressure chamber (48)
On the other hand, the second pressure chamber (40) is formed facing the other end (39a) of the actuating member (43), and the inflow passages (17, 17, ...) Or of the momentum detector (1) or A passage connected to the outflow passage (13, 13, ...) And the first pressure chamber
(48) is connected by a first control line having a restriction (66), while the passage and the second pressure chamber (40) are connected by a second control line having a restriction (69), The downstream side of the throttle (66) in the control line is connected to any one of the inlet ports, while the downstream side of the throttle (69) in the second control line is connected to another inlet port, The change in the momentum of the substance of the fluid that flows into the detection body (5) through the passages (17, 17, ...) And flows out through the outflow passages (13, 13, ...) The first pressure chamber (48) and the second pressure chamber that are balanced with the axial force acting on
A flow rate detector characterized by comprising pressure measuring means for detecting a pressure difference from the (40) as mass flow rate information of the fluid flowing in the detection body (5).