JPS5850424A - Measuring device for flow rate of fluid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The present invention relates to the measurement of fluid flow rates and, more particularly, to apparatus for measuring characteristics of flow meters.

U.S. Patent No. 4,152.92, issued May 8, 1979 to Nidward E. 7 Lancisco, Jr.
2 discloses a ballistic flow measuring device of the type in which a measuring piston made to move within a measuring cylinder and a control piston made to move within a control cylinder are connected by a rod. has been done. The measuring cylinder is connected in series in a fluid line with a flow meter whose properties are to be measured. Compression=5= An air source is provided and connected to the control cylinder with compressed air pressure applied alternately to both sides of the control piston. Air pressure is adjusted to control control piston movement within the control cylinder during operation of the measuring device.

If the rod is coupled to only one side of the measuring piston, the area that can be exposed to fluid on one side of the measuring piston is reduced. This also applies to the other side. As a result, an undesirable pressure difference occurs in the measuring piston, which slows down its movement during the measuring operation. To eliminate this differential pressure, one embodiment of the measuring device described in the aforementioned patent no. 4,152,922 employs a rod connected to opposite sides of the measuring piston and extending through it. are doing. This rod also extends beyond the end of the measuring cylinder opposite the control cylinder, so that the measuring device occupies considerably more space.

The invention provides an example of using a pressure gas filled chamber to compensate for the pressure difference. This plenum is connected to the control cylinder with gas pressure applied to the control piston, in order to compensate for the unbalanced pressure caused by the = 6 rod and the frictional forces exerted on the measuring piston during its movement within the measuring cylinder. ing. Thanks to the gas delivered from the plenum, the control piston is subjected to an approximately constant compensation pressure, independent of its position within the control cylinder.

SUMMARY OF THE INVENTION In the present invention, the characteristics of a flow meter are measured by using a pressure gas-filled chamber to compensate for the differential pressure within the device. Specifically, the fluid displacement measuring cylinder has an inlet portion and an outlet portion near both ends thereof. A fluid displacement ω measurement piston is configured to move within the measurement cylinder in the form of a fluid barrier body, and a control piston having first and second sides is configured to move within the control cylinder in the form of a fluid barrier body. It is being The control piston is connected by a rod only to the side of the measuring piston facing the nine measuring cylinders. The pressurized gas-filled chamber is connected to the control cylinder in such a way that the pressure of the pressurized gas presses the measuring piston towards the other end of the measuring cylinder. The movement of the measuring piston in the measuring cylinder was sensed and the movement of the control piston in the control cylinder was fluidically controlled.

Although the filling chamber has a significantly larger volume than the control cylinder, its pressure is selected to counteract the unbalanced pressure caused by the rods.

The device according to the invention therefore allows for a significant reduction in length, since the rod does not have to extend between the ends of the measuring cylinder and protrude from the end of the measuring cylinder opposite the control cylinder.

The invention also provides for a source of pressurized liquid to be connected to the control cylinder in such a way that the pressure of the pressurized liquid is applied to the side of the control piston opposite to the side on which the gas pressure from the plenum is applied. The pressure of the liquid in the control cylinder is automatically adjusted to control the movement of the measuring piston. Due to the incompressibility of the liquid, the measuring piston reacts rapidly to change commands and at the same time adapts to compensating effects of unbalanced pressures and frictional forces caused by the rod. Preferably, control
- The pressure of the liquid in the control cylinder is preferably controlled in such a way that the pressure difference between the two ends of the measuring piston in the measuring cylinder is maintained constant. As a result, during the measurement operation, the movement of the measuring piston within the measuring cylinder has virtually no or little relation to the flow rate and/or density of the tube fluid, even if the tube fluid is a gas. No impact.

The features of specific embodiments which are believed to be the best suited for carrying out the invention are illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF A SPECIFIC EMBODIMENT In FIG. 1, a measuring device 10 is connected in series with a measured flow meter 12 in a fluid conduit 14. In FIG. The measuring device 10 is equipped with a measuring cylinder 16 having an inlet 18 and an outlet 20 connected to a fluid line 14 . The measuring piston 22 is designed to carry out a displacement movement within this measuring cylinder 16 in the form of a fluid barrier. The measuring piston 22 is provided with a plurality of openings 24 to allow fluid to flow from the fluid line 14 into the measuring cylinder 16 when the measuring piston 22 is at rest. A poppet valve 26 is provided, which is constructed such that it can be moved toward and away from the opening 24-- to close or open the fluid passage formed by the opening. ing. The control cylinder 28 is joined to the prosthetic end of the cylinder 16 in axial alignment with the measuring cylinder 16 .

A control piston 30 is made to move within this control cylinder 28. The poppet valve 26 and thus the measuring piston 22 are connected via a rod 32 to a control piston 30 . Rod 32 is connected only to the upstream side of piston 22 and to that side of control piston 30.

For a description of the specific construction of the various components of the measuring device 10, including the sealing members and bushings and various components described below, see U.S. Pat. No. 152,922.

The poppet valve 26 can be considered part of the measuring piston 22 as far as the pressure applied to it by the fluid line 14 is concerned. As a result of connecting the rod 32 only upstream of the poppet valve 26, the area upstream of the measuring piston 22 on which the fluid in the fluid line 14 acts is smaller than the downstream area of a similar measuring piston 22. . For this reason, an imbalance of force occurs that presses the measuring screw 22 toward the upstream end of the measuring cylinder 16, and therefore movement of the measuring piston 22 from the upstream end of the measuring cylinder 16 to the downstream end is hindered. become. Cylinder 1 for Vistka 30
Dynamic frictional force is added when moving within the 6, which also hinders movement. If the displacement movement of the measuring piston is impeded, the flow rate will be affected or changed and excessive pressure fluctuations will occur in the fluid flowing within the tube 14. In order to compensate for and cancel out such unbalanced pressures and frictional forces, a plenum chamber 34 is connected to one end of the control cylinder 28, ie to the end opposite to the end on which the measuring cylinder 16 is located.

This filling chamber 34 is filled with pressurized gas supplied from a gas supply source 35. The pressure of the gas in the filling chamber 34 is due to the unbalanced pressure exerted on the measuring piston 22 by the rod 32 on the side of the control piston 30 opposite the measuring piston 22 and the movement of the control piston 30 in the measuring cylinder 16. It is desirable to select the most suitable value for applying a force that is equal in magnitude to the dynamic friction force generated between the sealing member, bushing, etc., and opposite in one direction. . This optimum fill gas pressure value is determined by the flowmeter response value when the control piston 30 is in its standby or upstream position and the measurement cylinder 16 of the control piston 30.
Determined by comparing the response values of the flowmeter during internal movement. The filling chamber gas pressure is adjusted until these two response values are equal.
That is, the movement of the control piston 30 into the measuring cylinder 16 continues until the piston 30 no longer impedes the flow of fluid in the fluid line.

The optimum pressure within the filling chamber 34 varies as a function of the static fluid pressure within the fluid conduit 14. In order to make accurate measurements,
If the above procedure is preferably carried out prior to each operation, or if the static pressure can be measured prior to the measurement operation, such as with a pressure probe 31 in the fluid line 14, then after this pressure measurement, the filling chamber 34 Based on this, adjust the pressure inside to obtain the optimum value. For this purpose, the gas supply source 35 is connected to the filling chamber 34 via a manual control valve 43;
A pressure gauge 45 and a vent valve 41 are arranged in the filling chamber 34. The pressure of the gas supply 35 is 19 - greater than the maximum required to pressurize the plenum chamber 34 . The volume of the plenum chamber 34 is significantly larger than the volume of the control cylinder 28, for example 30 times or more, so that the pressure of the gas supplied from the plenum chamber 34 remains approximately constant even if the volume of the control cylinder 28 changes. It is maintained.

In order to sense the movement of the measuring piston 22 within the measuring cylinder 16, an elongated housing 33 having a longitudinal axis parallel to the axis of the control cylinder 28 is coupled to the end of the measuring cylinder 16;
Optical sensors 36, 37 and 38 are mounted inside this housing 33 along the longitudinal direction. cylinder 1
Piston 22 in 6 and light shielding 1144 in housing 33
0 are connected by a rod 39.

Optical sensors 36, 37 and 38 each consist of a photovoltaic cell and a light source aligned with the photovoltaic cell and projecting a beam onto the rechargeable battery. As the piston 22 moves within the cylinder 16, the shading group 40 moves within the housing 33 and sequentially engages the optical sensors 36, 37 and 3.
8 beams are blocked and electrical pulse signals are sequentially generated.

Optical sensor 36 is located at a position within rung 33 that corresponds to the two-fluid rest position of piston 22 within cylinder 16 . The optical sensor 37 is positioned at a position within the housing 33 that corresponds to the position of the piston 22 within the cylinder 16 at the starting position of the measurement interval. That is, the piston 22 is preferably located one minute away from the upstream position of the piston 22 so that the piston 22 can move synchronously with the fluid flowing within the tube 14. The optical sensor 38 is positioned in the housing 33 at a position corresponding to the screw 8222 at the end of the measurement interval near the downstream end of the cylinder 16.

Sensors 36, 37 and 38 are connected to a control console 44 by a cable 42. The output of the flow meter 12, which may be, for example, an electrical pulse signal whose frequency is proportional to the flow rate, is connected to a control console 44 by a cable 46. The console 44 contains electronic circuitry for measuring the characteristics of the flowmeter 12. It may also be constructed from the circuit shown in FIG. 8 of US Pat. No. 3,403,544, the disclosure of which is incorporated herein by reference in its entirety. This built-in circuit 14- in the console 44 is connected to the sensors 36 to 38 and m m fft 12
generates a value indicative of the flowmeter characteristics in response to an electrical signal generated by the flowmeter, which value is displayed by the console 44.

Control piston 30. The movement of the measuring piston 22 is therefore:
It is controlled by a hydraulic open-loop controller.

A reservoir 48 stores an incompressible fluid, preferably a suitable hydraulic oil. Hydraulic fluid is supplied from reservoir 48 to the input of pump 50 . This fluid is routed from the pump 50 output to the portion of the cylinder 28 that is between the piston 30 and the upstream end of the cylinder 16 and to the input of the two-way fluid loaf dump valve 52 . Valve 52 is connected to cable 5 from console 44.
Operate via 3.

The output of the dump valve 52 is connected to the storage tank 48 via a servo control valve 54 . Valve 54 is operated from console 44 via cable 55. The pump 50 is driven by a constant speed motor 51. Pump 50 is a constant pressure, variable displacement pump that generates a pressure slightly greater than the gas in fill chamber 34 . This pressure is large enough to overcome not only the gas pressure applied to the piston 30, but also the frictional force and the fluid pressure in the fluid line, and is therefore a pressure capable of driving the piston 16-22 in the upstream direction. be.

The differential pressure (Ap) feeding device 56 is connected to each cylinder 1.
a pair of input boats in fluid communication with the upstream and downstream ends of console 4 via cable 58;
and an electrical output section connected to 4. The Ap delivery device 56 is arranged between a region of the cylinder 16 upstream of the piston 22 and a region of the cylinder 16 downstream of the piston 22 when the opening 24 is closed by the poppet valve 26 and the piston 22 moves within the cylinder 16. generates an electrical output signal proportional to the differential pressure of

As shown in FIG. 2, the control console 44 includes characterization electronics 70, which may be the circuit shown in FIG. 8 of U.S. Pat. No. 3,403,544. is also possible. The disclosure content of this patent is fully incorporated into the present application by reference. Cables 42 and 46 connect to the inlet of circuit 70 and
The output section 0 is connected to the recording/instruction device 72. In response to the electrical pulse signals generated by the sensors 37 and 38 when the beam is blocked by the blocking group 40 and the electrical signal generated by the flow rate reduction characteristic, the circuit 10 generates a flowmeter characteristic value;
This value is displayed by the recording and indicating device 72. The cable 42 and the activation command terminal are connected to the input of the matching circuit 74.

- The output of the number circuit 74 is connected to the input of the interval timing mechanism 76, and the output of the mechanism 16 is connected to the set input of the bistable circuit 78. The optical sensor 38 is a bistable circuit 78
Connected to the reset input of the The ΔD feed device 56 is connected via a cable 58 to the input of a servo amplifier 80, the output terminal of the servo amplifier 80 is connected via an electronic switch 82 and a cable 55 to a control input terminal of the servo control valve 54. . The output terminal of bistable circuit 78 is connected via cable 53 to a control input terminal of dump valve 52 and to a switching input terminal of electronic switch 82 . When the beam of sensor 36 is interrupted and an activation command signal appears at terminal 71, minus number circuit 74 triggers interval timing mechanism 76. At the end of the measured time interval, mechanism 76 sets bistable circuit 78. When the bistable circuit 78 is set, the dump 52 valve opens and the electronic switch 82 closes, thus establishing a return path from the An17-16- feeding device 56 to the servo control valve 54. When the sensor 38 beam is interrupted, the bistable circuit 78 is relit, the dump valve 52 is closed, and the electronic switch 82 is opened, so that the return path from the Ap feed device 56 to the servo control valve 54 is open. become.

In operation, prior to the measurement operation, the dump valve 52 is closed, the piston 22 is positioned at the upstream end of the cylinder 16, the beam of the sensor 36 is blocked, and the electronic switch 82 is closed.
and the poppet valve is held open by the pressure of the hydraulic fluid applied to the side of the piston 30 on the cylinder 16 side.

To open the piston 22 for measurement operations, an activation command is input to the terminal 71. After a timed interval, dump valve 52 opens and electronic switch 82 closes. As a result, cylinder 16
The fluid pressure on the side of the control piston 30 decreases, and the combined effect of the gas pressure on the opposite side of the piston 30 and the movement of the fluid flowing in the fluid line 14 causes the poppet valve 26 to close the opening 24; The piston 22 begins to move downstream within the cylinder 16, and the return path between the Ap lifting device 56 and the servo control valve 54 is activated, thereby causing a A constant pressure difference is achieved between. Since the control fluid is incompressible, i.e., a fluid, the control device senses the Ap delivery signal by adjusting the fluid pressure and thus varying the pressure on the side of the piston 30 coupled to the rod 32. It is possible to quickly react to pressure difference fluctuations and cancel out these pressure difference fluctuations. Although this constant differential pressure can be set to zero, it is preferable that the pressure on the downstream side of the piston 22 is made slightly larger than the pressure on the upstream side. By the time the piston 22 reaches a certain position within the cylinder 16, i.e., the sensor 37 beam blocking position, the piston 22 is in synchronous motion with the fluid flow within the fluid line 14, and the servo control valve 52 is A constant pressure difference is achieved between the upstream and downstream sides of the piston 22, and as a result, fluctuations in the flow rate of the fluid flowing within the tube 14 are minimized. When the piston 22 reaches the downstream end of the cylinder 16, a stopper (not shown) stops the piston 22.
absorbs the shock and opens the poppet valve 26. In addition,
This is as described in US Pat. No. 4,152,922. When the beam of the sensor 38 is interrupted, the electronic switch 82 is opened to stop the return path and the dump valve is closed to return fluid pressure to the side of the piston 30 on the cylinder 16 side.

The piston 22 is driven by the fluid pressure applied to the piston 30, the poppet valve 26 is opened, and the downstream end and upstream end of the cylinder 16 are brought into communication. When piston 22 reaches the upstream end of cylinder 16, one measurement operation performance cycle is complete. After the timing mechanism 76 has timed an interval sufficient to allow the fluid turbulence to subside, the cycle is automatically repeated until the activation command is removed from the terminal 71.

In summary, gas in cylinder 28 contacting the side of piston 30 opposite rod 32 exerts a constant pressure on piston 22 through piston 30 and rod 32;
Thereby, the unbalanced pressure and the frictional force applied to the piston 22 can be canceled out. In use, the liquid in the cylinder 28 that is in contact with the side of the piston 30 on the same side as the rod 32 flows through the piston 30 and the rod 32 to the piston 22.
A variable pressure can be applied to maintain a constant pressure differential across the piston-90-22.

As a result of these fluid pressures being applied to the piston 22 via the piston 30 and the rod 32, the flow of fluid flowing within the fluid pipe 14 is hardly disturbed by the movement of the piston 22, and therefore the movement of the piston 22 is caused by the movement of the piston 22. There is virtually no or little impact on either or both the flow rate and flow of fluid within 14.

Instead of the circuitry of FIG. 2, the device can also be operated automatically under microprocessor control. This means that the microprocessor can process and evaluate the measurement data and, if necessary, also carry out statistical analysis of the data. Alternatively, dump valve 52 and electronic switch 82
can be manually operated to perform one or more measurement operation cycles.

The embodiments of the present invention described above are merely preferred and illustrative examples for illustrating the idea of the present invention, and are not intended to limit the scope of the present invention. Those skilled in the art can devise a wide variety of other configurations without departing from the spirit and scope of the invention. For example, although the fluid pressure control system described herein is a preferred embodiment when the fluid within the tube is compressible, ie, a gas, the present invention may be practiced without the use of this system. In other words, this system is not desirable if the fluid within the tube is incompressible, ie, liquid. Although the dump valve and the solenoid control valve are arranged in series in the figure, they can also be arranged in parallel. The control and measuring cylinders can also be arranged in parallel rather than in axial alignment. For parallel configuration,
The rod has a U-shaped configuration and the pressure gas supplied from the plenum will apply pressure to the rond connection side of the control piston. Alternatively, the control cylinder may be axially aligned with the downstream end of the measurement cylinder. The hydraulic control device for supplying liquid into the control cylinder can be used to perform one, two or three of the three functions mentioned above. That is, there is a function to hold the measuring piston in an upstream position, that is, a standby position prior to the measuring operation, and release the measuring piston at the start of the measuring operation, and a function to maintain the pressure difference between the two ends of the measuring piston during the measuring operation. There are three functions: maintaining the piston constant, and returning the measurement operation start constant piston to the upstream position. However, especially when the fluid in the pipe is gas, these three
A usage method that utilizes all functions is desirable.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a test rig incorporating the principles of the present invention, and FIG. 2 is a diagram illustrating the control console of FIG. 1 and some of the other components selected from the test rig. FIG. 2 is a detailed schematic block diagram. DESCRIPTION OF SYMBOLS 10... Measuring device 12... Flow meter 16... Measuring cylinder 22... Measuring piston 24... Opening part 26... Poppet valve 28... Control cylinder 30
...Control piston 32...Rod 34...Full chamber 35...Gas supply source 36.37.38...
Optical lenser 39...Rod 40...Shading flag
44...Control console 48...Storage tank Muto pump 52...Dump valve 54...Servo control valve
56...Differential pressure feeding device 23-Continued from page 1 Priority claim @July 30, 1981 [Inc.] United States (US
) [Yes] 288338 @ Applicant Nidward Elsworth Francisco Jr. 3400 Flaremont, Paradise Valley, Alisina, 85253 United States of America November 1988 Commissioner of the Japan Patent Office Kazuo Wakasugi 1 Case Description Patent Application filed in 1988 No. 131060 2, Title of the invention: Fluid flow rate measuring device 3, Relationship with the amended person's case Name of patent applicant: Flow Chikunoroshii, Representative of Incorporated -'1 Yi, Yi Francisco, Jr. 4, Agent

Claims (12)

[Claims] (1) A fluid displacement measuring cylinder having an inlet and an outlet near both ends, a fluid displacement measuring piston configured to move within the measuring cylinder in the form of a fluid barrier, and a control cylinder. , a control piston adapted to move in the form of a fluid barrier in the control cylinder; a rod connecting the control piston only to the side of the measuring piston facing one end of the measuring cylinder; a device for sensing the movement of the measuring piston in a measuring cylinder; a pressure gas-filled chamber; and the filling chamber and the control cylinder are located on one side of the control piston. A device for coupling the measurement piston in such a manner that applied gas pressure pushes the measurement piston toward the other end of the measurement cylinder; and a device for fluidically controlling the movement of the control piston within the control cylinder. Fluid flow measurement device. (2) the control cylinder is axially aligned with one end of the measurement cylinder, the rod is linear in shape, and the coupling device connects the plenum chamber and the control cylinder;
Apparatus according to claim 1, wherein the gas pressure is coupled in a positive manner to the side of the control piston opposite the measuring piston. (3) the control device includes a source of fluid at a higher pressure than the plenum, and alternately supplies pressurized fluid from the source to and removes pressurized fluid from the side of the control piston facing the measurement piston; The device according to claim 2, comprising a member that performs the following actions. (4) a fluid supply connected to the inlet and a fluid receiver connected to the outlet, the gas pressure value of the filled chamber being as a result of the measurement from the fluid supply; A value that generates a pressure on the control piston equal in magnitude and opposite in direction to the sum of the unbalanced pressure exerted on the measuring piston by the static pressure of the fluid flowing through the cylinder and the frictional force of the measuring piston. Apparatus according to scope (3). (5) The apparatus according to claim (4), wherein the measuring piston includes an opening for fluid flowing within the measuring cylinder and a member for opening and closing the opening. (6) The opening/closing member comprises a poppet valve arranged between the inlet and the opening in the form of a part of the measuring piston, and the poppet valve closes and opens the opening. a feature z' [Claim No. 5 ). (7) The motion control device includes: a liquid supply device; a device that connects the liquid supply device and the control cylinder in a state where liquid pressure is applied to the other side of the control piston; 3- inside the control cylinder; The device according to claim (1), comprising: a device for controlling the pressure of a liquid; and a device for controlling the pressure of a liquid. (8) The apparatus according to claim (7), further comprising a gas source connected to the inlet and a gas receptor connected to the outlet. (9) The liquid pressure control device in the control cylinder includes a device that senses the pressure difference between both ends of the measuring screws 1 to 1, and responds to the sensing device to adjust the pressure of the liquid in the control cylinder to 9. The device according to claim 8, comprising a device for canceling out fluctuations in the pressure difference across the measuring piston. (10) The liquid pressure regulating device in the control cylinder includes a device that senses a pressure difference between both ends of the measuring piston, and responds to the sensing device to adjust the pressure of the liquid in the control cylinder to adjust the pressure of the liquid in the measuring piston. 7. The device according to claim 7, comprising a device for canceling fluctuations in pressure difference between both ends. (11) The measuring piston has a through-shaped opening forming a passage for allowing fluid to flow from the inlet to the A-outlet, and a movable poppet valve for opening and closing the opening. An apparatus according to claim (10) comprising: (12) The rod is connected to the measuring piston via the poppet valve, and the poppet valve can be opened and closed by movement of the rod.
).