KR900003164B1 - Flowmeter calibrator by compact piston pusher - Google Patents

Abstract

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Description

Flowmeter calibrator by compact piston pusher

1 is a schematic diagram of a measuring cylinder.

2 is a block diagram of a flowmeter calibration apparatus using a compact piston pusher.

3 is a flow chart of the operation of the flowmeter calibration device by the compact piston pusher.

The present invention aims to quickly and accurately calibrate a flowmeter installed at a production site (as part of a pipeline) without interrupting the production process and shipping process.

Conventionally, when the flowmeter is to be calibrated, the flow gauge installed as part of the pipeline is dismantled and then attached to the calibrator to be calibrated.

If the flowmeter is dismantled, the process must be stopped because fluid cannot flow inside the pipeline. In addition, when calibrating a flow meter in a calibration device, the accuracy of the calibration is reduced because the flow meter cannot always measure with the same fluid as the fluid measured in the field.

The present invention overcomes these shortcomings and improves the accuracy of flow measurement and calibration. The compact piston pusher can be installed with the flowmeter in the pipeline where the flowmeter is installed to improve the accuracy of the calibration by calibrating the flowmeter under the same conditions-such as fluid, temperature and pressure.

In addition, since it is installed in the flow meter and the pipeline, it is not necessary to dismantle the flow meter from the pipeline, so that it can be calibrated without stopping the process.

In particular, the compact piston pusher is operated by a computer (figure 2) so that the flowmeter's accuracy can be checked at any time or on a regular basis as needed, and can be operated without human assistance.

Therefore, it is possible to greatly improve the accuracy, speed and productivity than calibrating the flow meter by conventional calibration devices (weight calibration device, volumetric calibration device).

Hereinafter, the gist of the present invention will be described in detail with reference to the accompanying drawings and the configuration and effects.

In FIG. 1, the basic drawing of the present invention is for calibrating the flowmeter 1 to be calibrated. When the fluid having passed through the flow meter 1 passes through the measurement cylinder 2b, the piston 3 inside the measurement cylinder 2b moves to the pneumatic cylinder 17. At this time, the pulse counter 12 measures the pulse generated by the calibration target flow meter 1, and starts measuring when the measuring rod 11 passes the detection switch 4 and ends the measurement when passing the detection switch 5. It is connected to the pulse counter.

The measuring stroke refers to the movement of the piston 3 from the sensing switch 4 to the sensing switch 5 by the pressure of the measuring fluid. The return stroke refers to the air pressure 18 supplied to the pneumatic cylinder 17 in the direction opposite to the measuring stroke. Says to go by.

Thus, the calibration of the flowmeter is made at the measurement stroke, and the regression stroke is the process of preparing it back to its original launch position (position 1) for the measurement stroke.

Therefore, no measurement is made in the return stroke and the bypass valve 6 is opened so that the fluid passes through the bypass valve 6 so that the return stroke is smooth.

The cylinder 2 is composed of an external cylinder 2a and an internal measurement cylinder 2b so as to reduce errors caused by changes in temperature and pressure that may occur in the measurement.

In other words, all materials expand with increasing temperature or pressure, and must be compensated for when measuring.

However, since the present invention uses a double cylinder, the internal measuring cylinder 2b used for the actual measurement does not need correction because the same pressure acts on the inside and outside of the cylinder.

In addition, since the measuring cylinder is inside the flowing fluid, it is possible to maintain a constant temperature and the temperature distribution of each part of the cylinder is constant. Therefore, by measuring the temperature of the fluid it is possible to correct the change in the volume of the measuring cylinder.

Apparatuses for assisting the operation of the piston include a launch cylinder (9), bypass valve (7), brake port (15), adjusting screw (16), and the like.

These devices act to allow the piston 3 to accelerate quickly and maintain a constant speed and then stop without mechanical impact when stopped.

The bypass valve 6 is open when the cylinder 9 is in the launch position (1st position) for the measurement stroke, and the switch 19 detects this when the bypass balance is completely closed for measurement and the launch cylinder 9 ) By supplying hydraulic, pneumatic or spring pressure (10) to the piston (3) to move. At this time, since the piston 3 must reach a constant speed within a short time, it is necessary to stabilize the movement of the piston 3 when the force for moving the piston 3 changes from hydraulic pressure, air pressure, or spring pressure 10 to the pressure of the fluid. To this end, the bypass port 7 has the same shape as the first degree.

The bypass port 7 has an elliptical shape in the axial direction and is evenly disposed around the measurement cylinder 2b.

The constant speed of the piston (3) here is important because it means to maintain a constant flow rate.

By increasing the overall length of the cylinder to stabilize the speed, the efficiency of the system is reduced, so that the bypass port 7 is elliptical in the axial direction. Since the bypass port 7 is an ellipse, the pressure of the fluid moving the piston 3 is applied to the piston 3 in the form of a first function, so that the speed of the piston 3 can be stably increased.

If the bypass port 7 is not elliptical in shape, the pressure of the fluid is applied to the piston 3 in the form of a STEP INPUT. Since the piston increases in speed as an OVERSHOOT, the speed becomes unstable. .

Therefore, the initial stability is very important for speed stabilization in the measurement stroke of the piston (3). Once the stable speed is reached at the initial stage, the equilibrium velocity is balanced with the frictional force of the piston and the contact surface with the fluid pressure at the preset flow rate. work out.

In addition, since the elliptical bypass port 7 is uniformly arranged in the measuring cylinder 2b in the circumferential direction, the pressure of the fluid acts evenly on the piston 3 to facilitate the movement of the piston 3.

That is, the piston 3 is not caught inside the measuring cylinder 2b due to the imbalance of the force acting on the piston 3 during the movement.

On the other hand, when the piston 3 stops at the end of the measuring stroke, it is necessary to stop it quickly without mechanical impact. An apparatus for stopping the piston 3 includes an expansion pipe 14, a downstream bypass port 8, a brake port 15, and an adjustment screw 16.

Once the piston (3) has passed the downstream sensing switch (5), once the measurement is finished, the piston (3) must be stopped without impact.

When the piston comes in the expansion tube 14, the fluid flows between the head of the piston 3 and the gap of the expansion tube to the downstream bypass port 8. At this time, since the piston 3 receives only the force acting on the area of the head of the piston 3, the moving force is weakened and stopped, but the battery continues to move forward to the brake port 15 due to the inertia.

When the piston head enters the brake port 15, the internal fluid is compressed, so that the piston head is stopped by the compression of the fluid without mechanical impact. The braking force due to the compression of the fluid varies depending on the piston speed, that is, the flow rate.

In other words, in order to stop the piston 3 and the packing of each part without mechanical damage, the braking force is adjusted by the adjusting screw 16.

The operation of the compact piston prober can be divided firstly into the measuring stroke and the return stroke. In the measurement stroke, the flowmeter is calibrated, and the regression stroke refers to the process of returning the piston 3 to its original position to perform the measurement stroke.

In order to understand this process, it is necessary to understand the flow of the fluid according to the operation of the bypass valve 6 and the piston 3.

When the operation is shown in sequence, the bypass valve 6 is opened when the piston 3 is in the upstream position as the first degree.

At this time, the fluid passing the calibration target flow meter 1 passes through the bypass valve 6 and returns to the original line (the line used in the field state). The bypass valve (5) closes for the first time when the computer commands the measurement (see Figure 2).

At this time, the fluid enters the cylinder 2, passes through the upstream bypass port 7, passes through the downstream bypass port 7, and passes through the downstream bypass port 8 and passes through the outlet.

However, in order to shorten the measurement time and increase the efficiency of the system, when the bypass valve 6 is completely closed, the sensing switch 19 attached thereto detects this and supplies hydraulic, pneumatic or spring pressure to the launching cylinder 9. Push the head of the cylinder (3) down to the upstream bypass port (7). From this time, the fluid moves through the sensing switches 4 and 5 while pushing the piston 3.

When the passage of the sensing switch 5 is confirmed by the computer, the measurement process is finished once, and the various readings (pulse, temperature, pressure, etc.) are read by the computer, calculated and stored.

Apart from the calculation and storage, when the piston 3 confirms the passage of the sensing switch 5, the computer commands a return stroke.

First, the bypass valve 6 is opened to directly pass the fluid. When the detection switch 19 confirms that the bypass valve 6 is opened, the hydraulic pressure or air pressure is supplied to return the piston 3 to its original launch position (the position in FIG. 1).

This completes the measurement and regression process and waits for the computer command for the next measurement.

Therefore, in the revolving stroke, the compact piston pusher does not calibrate the flowmeter 1, but can be calibrated only in the measuring stroke.

For reference, the measurement of the fluid in the actual line is performed by the flow meter 1 and the present invention is to check whether the measured value of the flow meter is accurate.

2 shows the state when the compact piston prober is configured as a system and installed in the field as a flowmeter calibration device.

Therefore, FIG. 1 illustrates the detailed configuration and operation of the compact piston pusher including the measuring cylinder, and FIG. 2 illustrates the collection of measurement data and the operation of control signals.

All measurements are collected once by the storage and control unit, which the microcomputer determines and commands the control unit.

The control unit supplies compressed air to the cylinder through the solenoid valve of the pneumatic logic circuit to operate the compact piston pusher.

Information to be measured includes pulses, sense switches, signals from D1 and D2, bypass valve actuation switch signals, and temperature and pressure measurements directly input from the flowmeter to be calibrated.

Signals to be controlled according to these measurement values include a bypass valve operation signal PB, a launch cylinder operation signal PL, a measurement stroke assist signal PA, a regression stroke signal PR, and the like.

Looking at the sequence of operation, as shown in Figure 3, the operation and collection of data is made in a sequential (SEQUENTIAL).

Referring to FIG. 3, the bypass valve is open in the initial state, and the measurement and control signals do not operate.

First, when the computer commands the measurement, the bypass pressure (PB) is supplied and the valve starts to close. When the valve is completely closed, the bypass valve detection switch operation switch (PBS) detects this and simultaneously launches cylinder pressure (PL) and assist pressure (PA). To supply.

At this time, it corresponds to PRE-RUN and the piston 3 of FIG. 1 maintains a stable speed past the upstream bypass port 7.

As the piston 3 moves at a stable speed, it starts to measure the pulse coming from the flow meter to be calibrated through the sensing switch (D1 in FIG.

The piston (3) continues to move and passes through the sensing switch (5 in Fig. 1, D2 in Fig. 3) and the measurement stroke is finished. The computer, which judges this, commands the controller to launch the cylinder pressure (P2) and assist pressure (PA). ), The computer collects all measurement data.

When the computer has finished collecting data, the regression process (Figure 3 RETURN STROKE) begins. The return stroke causes the control device to open the bypass valve (6 in FIG. 1) when the computer has finished collecting data and the bypass valve detection switch (19 in FIG. 1) detects this and opens the cylinder (17) for the return stroke. ) Hydraulic pressure, pneumatic pressure and spring pressure (18 in FIG. 1).

When the piston (3 in FIG. 1) reaches its original true position (position in FIG. 1), all measurement and J signals are reset to initial state as in FIG.

Therefore, the next measurement can be made, and the computer can calibrate the flow meter to be calibrated ((1) of FIG. 1) while repeating this process according to the program.

In general, it is very important for the calibration device to keep this flow rate stable because the flow rate is changed according to the PLOWRATE.

That is, in order to characterize and calibrate the flowmeter, the calibration device must be able to maintain a stable flow once.

Since the compact piston pusher is also a calibration device, it is important to keep the flow rate stable, that is, to keep the speed of the piston constant.

The stability of the piston speed is important for the initial velocity stabilization. When the initial steady velocity is achieved, the equilibrium motion of the fluid and frictional force is balanced.

In order to stabilize the movement of the initial piston 30 for the constant velocity movement, the switch 19 attached to the bypass valve 6, the launch cylinder 9, the upstream bypass port 7, etc. It works in combination.

In addition, the switch 19 and the switch 4 and 5 are the sensing switches which operate separately.

The switch 19 is attached to facilitate the operation of the piston 3 and to make the operation of the system efficient (without waiting time).

In other words, it transmits the information on the opening and closing of the bypass valve 6 to the control device serves to enable the operation of the launching cylinder (9) immediately.

The switches 4 and 5 start and end the pulse signal measurement sent by the calibration flow meter 1.

In other words, it transmits the information on the opening and closing of the bypass valve 6 to the control device serves to enable the operation of the launching cylinder (9) immediately.

The switches 4 and 5 start and end the pulse signal measurement sent by the calibration flow meter 1.

That is, the principle of compact piston pusher measurement is the number of pulses sent while the piston 3 moves between the sensing switches 4 and 5 and the volume of fluid that flows while passing the calibration flow meter 1 by the volume thereof. To compare.

Therefore, from the moment the piston 3 passes the detection switch 4, the measurement of the pulse from the calibration target flowmeter 1 starts, and the measurement stops the moment it passes the detection switch 5.

Therefore, the switch 19 is a separate switch having a role and a function different from those of the switches 4 and 5.

The present invention having such a configuration and action effect is easy to install in a marine oil field, such as the installation area is small and can be calibrated in the environment, such as the use conditions can reduce the errors that can occur in the change of the measurement fluid or measurement conditions In particular, since the flowmeter is calibrated in the process line, it is possible to eliminate non-economic factors such as process interruption, collect data by the computer and control the device so that it can be calibrated quickly and save labor costs. It is widely available in the field.

Claims (6)

Connect the measuring cylinder (2) and the launching cylinder (9) having the pressure gauge (10), and form a bypass port (7) (8) inside the measuring cylinder (2) to install a piston (3) therein Is inserted into the pneumatic cylinder (17) with sensing switches (4) and (5) and the bypass piston (P) is connected with a bypass valve (6) to the gas flow meter (1) under the measuring cylinder (PROVER). Flowmeter Calibration Device The flowmeter calibration device according to claim 1, wherein the measuring cylinder (2) is a compact piston piston (OVER) having a double structure of an outer tube (2b) and an inner tube (2a). The flowmeter calibration device according to claim 1, wherein the bypass port (7) (8) is machined in an elliptical direction in the axial direction by a compact piston pusher (PROVER). 2. A flowmeter calibration apparatus according to claim 1, wherein the bypass ports (7) (8) are arranged around a cylinder of the inner tube (2a) by a compact piston piston (PROVER). 2. The pneumatic cylinder (17) according to claim 1, wherein a bypass switch (6) is provided with a detection switch (19) for detecting the start and completion of the operation, which is provided with a launch cylinder (9) and a detection switch (4) (5). Flowmeter calibrator by COMPACT piston piston louver electrically connected to the unit. The compact (COMPA-) according to claim 1, wherein the expansion pipe portion (14), the brake port (15), and the brake port adjustment screw (16) are provided in the singular or plural number at the rear end of the inner tube (2a) of the measuring cylinder (2). CT) Flowmeter calibration device by piston pusher

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