JPH054624B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure gauge testing device for calibrating a pressure gauge, for example, and particularly to generation of test pressure using a plunger pump.

[Prior Art] Conventionally, a weight-type pressure gauge tester has been used for setting the scale of pressure gauges and electric pressure gauges using Bourdon tubes or bellows, and for calibrating pressure indication values.

Figure 3 is a structural diagram of a weight type pressure gauge tester.
In the figure, 1 is an oil tank for transmitting pressure, 9
1 is a stop valve that opens and closes a pipe, 10 is a pressure gauge that undergoes calibration and pressure indication value calibration, 20 is a weight that serves as a standard for test pressure, 21 is a ram equipped with a pressure receiving part for the weight 20, and 22 is a pressure gauge for transmitting pressure. 23 is a piston for generating test pressure; 24 is a piston for generating test pressure;
2 is a handle for adjusting the test pressure generated by the piston 23, and 25 is a bed for holding a weight type pressure gauge tester.

A conventional weight-type pressure gauge tester is configured as described above. For example, a weight 2 corresponding to the test pressure for calibration is used.
0 is grounded to the ram 21, and the discharge pressure of the piston 23 is increased by operating the handle 24 while rotating the ram 21, and the weight 20 and the ram 21 are pushed up and balanced with the hydraulic pressure. The indicated value is the pressure equivalent to the weight 20 and ram 21.

P=W/AKgf/cm ² W: Total weight of weight 20 and ram 21 A: Effective pressure receiving area of ram 21 When the calibration is completed, operate the handle 24 in the opposite direction to reduce the discharge pressure of the piston 23. Lower the weight 20 and ram 21.

Next, when performing calibration using another test pressure, the weight 20 corresponding to the test pressure is installed on the ram 21 and the same operation as above is performed to calibrate the corresponding pressure.

As described above, the weights 20 corresponding to the test pressures to be calibrated are sequentially selected to calibrate the pressure gauges of various ranges and calibrate the pressure indications.

[Problems to be Solved by the Invention] In the conventional weight-type pressure gauge tester as described above, the weight 20 is used to generate the test pressure input to the pressure gauge 10.
Since the test pressure is different, the weight 2 is
Exchange 0. In particular, when performing calibration using a high test pressure of 350 Kgf/cm ² or more, a very heavy weight 20 is used and the operating force for the handle 23 is also large. Moreover, the work of installing the weight 20 on the ram 21 is a heavy labor, and the safety of the work becomes a problem.

Furthermore, each time the test pressure changes or the pressure range of the pressure gauge 10 changes, the handle 24 is operated to increase and decrease the discharge pressure of the piston 23 and the calibration test is repeated, so the calibration test of the pressure gauge 10 takes time. There was a problem in that it required a lot of work and the work efficiency was low.

This invention was made to solve this problem, and instead of using the weight 20 as a pressure standard, the calibration test of the pressure gauge 10 is performed by setting the test pressure with a setting device, making it easy to carry out light work with only a switch operation. The purpose of the present invention is to obtain a highly productive pressure gauge testing device that can be performed without requiring any skill, is highly safe, and requires short pressure gauge calibration time.

[Means for Solving the Problems] Therefore, the present invention provides a setting device that outputs an electrical signal calibrated at a test pressure, an electric pressure gauge that outputs an electrical signal in response to the test pressure, A servo amplifier to which a deviation signal between the setting device output and the electric pressure gauge output is input, a servo motor controlled by the servo amplifier output, and a plunger pump that outputs a discharge pressure that follows the operation of the servo motor. and a pressure booster cylinder that outputs a discharge pressure in response to a predetermined air pressure, and is configured to apply the pressure booster cylinder output to the plunger pump output via a check valve. did.

[Function] In this invention, the standard of the test pressure is based on the electric signal output by the setting device, and the test pressure is rapidly increased by the prepressure action of the pressure increase cylinder operated by air pressure at the beginning of the operation of the pressure gauge test device. After that, the discharge pressure of the plunger pump is controlled by the feedback servo system, which is activated by the deviation signal between the pressure set by the setting device and the output of the electric pressure gauge, and the test is automatically performed. The pressure is set to the set pressure. Therefore, the pressure gauge can be calibrated by electrically setting the test pressure using a setting device.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention, in which numerals 1, 9, and 10 are exactly the same as the conventional device described above. 2 is a command unit that controls the operation of this device; 3 is a command unit that operates according to the commands of the command unit 2;
Hydraulic solenoid valve that connects the pipeline from 4 is the command unit 2
5 is a pneumatic solenoid valve that is activated by a command and connected to a pneumatic source, and 5 is a plunger pump that is filled with oil from an oil tank 1 by the operation of a hydraulic solenoid valve 3, and whose discharge pressure increases in proportion to the output of the feedback servo. , 6 is a check valve that controls the direction of oil flow in the pipe, and 7 is filled with oil from the oil tank 1 through the check valve 6, and is operated by the primary air pressure, and the discharge pressure of the secondary hydraulic pressure. 8 is an electric pressure gauge that outputs an electric signal in response to the test pressure; 9 is a stop valve that opens and closes the pipe; 10
is the pressure gauge, 11 is the test pressure of pressure gauge 10 in decimal 3
12 is a servo amplifier into which the respective output signals of the electric pressure gauge 8 and the setting device 11 are input; 13 is a driver circuit for amplifying the output of the servo amplifier 12; 14 is a driver circuit for amplifying the output of the servo amplifier 12; The servo motor 15 is controlled by the output of the driver circuit 13, and 15 shows a case in which a coupler is used to mechanically connect the servo motor 14 and the plunger pump 5 that follows the servo motor 14 using a timing belt and a ball screw. ing.

In the pressure gauge testing apparatus configured as described above, the command unit 2 is operated to operate the hydraulic solenoid valve 3 to fill the plunger pump 5 with oil from the oil tank 1. On the other hand, the pressure increase cylinder 7 is filled with oil from the oil tank 1 via the check valve 6.The stop valve 9 is opened and the setter 11 is set to a test pressure of a pressure gauge 10 having a predetermined pressure range, for example 10. Set a digital switch that outputs an electrical signal calibrated using a 3-digit hexadecimal test pressure. When the air solenoid valve 4 is activated by operating the command unit 2, normally 7 kgf/cm ²
The pressure increasing cylinder 7 is actuated from the air pressure source via the air solenoid valve 4, and the discharge pressure of the hydraulic output increases rapidly, and at the same time, the indication on the pressure gauge 10 also increases. The discharge pressure from the pressure booster cylinder 7 depends on the pressure of the air pressure source, and the residual air in the measurement pipe of the test device including the pressure gauge 10 is rapidly compressed and raised to a predetermined pressure, making the pressure test efficient. Set it up so that it can be done.
The test pressure input to the pressure gauge 10 is simultaneously input to the electric pressure gauge 8, and the electric signal as a feedback signal due to the pressure and the digital setting signal of the setting device 11 are converted into analog signals and input to the servo amplifier 12, respectively. The deviation signal is applied to the servo motor 14 via the driver circuit 13 to control its rotation.

Since the setting device 11 has a digital setting structure for various pressure ranges, the notch of the setting device 11 can be adjusted to a predetermined test pressure by calibrating the digital setting value and each electric output of the electric pressure gauge 8 using the test pressure value. It can be used by setting it to the value of . Servo motor 1
The rotational movement of 4 is connected to the plunger pump 5 by a coupler 15 using a ball screw and a timing belt, for example, so that the backlash is extremely small, and the piston position is controlled, so that the plunger pump 5 generates a hunting movement. The output oil passage is connected to the output oil passage of the discharge pressure of the pressure boosting cylinder 7 via the check valve 6 and inputted to the pressure gauge 10, and the discharge pressure of the plunger pump 5 increases without any change. When the pressure becomes higher than the discharge pressure of the pressure boosting cylinder 7, the check valve 6 is activated, and thereafter the test pressure is increased only by the discharge pressure of the plunger pump 5 to match the pressure set by the setting device 11.

Therefore, the test pressure can be set in a short time with good responsiveness. The residual air in the measurement pipe is rapidly compressed by the preload effect of the discharge pressure of the pressure boosting cylinder 7, and then the plunger is driven by the servo motor 14 which is operated by the deviation output of the setting device 11 and the electric pressure gauge 7. Since the test pressure increases only due to the discharge pressure of the pump 5, by adjusting the gain of the driver circuit, the settling time of the control is made appropriate, and the settling of the test pressure to the set pressure is accurately matched, thereby increasing the accuracy of the test device. I'm trying to improve.

It is also possible to attach an indicator to the output of the electric pressure gauge 8 to indicate the test pressure and use it as a reference for the pressure gauge 10 to be calibrated.

As described above, in the present invention, the residual air in the measurement pipe is rapidly compressed by the prepressure action of the pressure booster cylinder 7 operated by air pressure at the initial stage of operation of the device, so that the settling time to the set pressure by the setting device 11 is reduced. The electric pressure gauge 8 outputs a highly accurate pressure signal, and a timing belt and ball screw are used to connect the servo motor 14 of the hydraulic control system and the plunger pump 5. The connector 15 with a very small backlash is adopted, and control is performed using a feedback servo system.
The occurrence of hunting during control is controlled and setter 1
A highly accurate test pressure is obtained that follows the set pressure of 1 very precisely.

Figure 2 shows the response characteristics of the test pressure. 17 is the discharge pressure of the pressure booster cylinder 7, 18 is the discharge pressure of the plunger pump 5. The test pressure increases rapidly at the beginning of the operation of this device, and near the set pressure, the pressure increases. Change will be slow.

Therefore, by using the pressure gauge testing device according to the present invention, the calibration test of the pressure gauge 10 can be performed quickly, accurately, and efficiently.

This avoids labor work such as selecting a weight 20 each time the test pressure changes, installing it on the ram 21, and controlling the discharge pressure of the piston 23 by operating the handle 24, which is required when using a conventional weight-type pressure gauge tester. By simply setting the test pressure by operating the digital switch of the setting device 11 and operating the switch of the command device 2, the pressure gauge can be calibrated in a short time and accurately. It goes without saying that the setting device 11 may be of an analog type using a variable resistor with a dial instead of a digital type.

[Effects of the Invention] As explained above, the present invention is equipped with a pressure booster cylinder operated by pneumatic pressure, and uses a feedback signal using an electric pressure gauge that responds to the test pressure with high precision and a deviation output of the setting device signal to control the plunger. With the simple structure that controls the pump discharge pressure, a preload effect acts on the increase in test pressure, which significantly shortens the time for the test pressure to settle to the set pressure, and the rate of change in the test pressure is slow near the set pressure. Therefore, the occurrence of hunting etc. is suppressed, and the test pressure can be accurately set to the set pressure in a short time.

Furthermore, since the pressure gauge testing device according to the present invention can be operated by simply operating a switch using a command device and setting the test pressure using a setting device, it is possible to perform light work with high safety and work efficiency without requiring the operation of handles on weights or cylinders. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a test pressure response characteristic diagram, and FIG. 3 is a structural diagram of a conventional weight type pressure gauge tester. In the figure, 1 is an oil tank, 2 is a command unit, 3 is a hydraulic solenoid valve, 4 is a pneumatic solenoid valve, 5 is a plunger pump, 6 is a check valve, 7 is a pressure booster cylinder, 8 is an electric pressure gauge, 10 is a pressure gauge, 11 is a setting device, 1
2 is a servo amplifier, 13 is a driver circuit, 14 is a servo motor, and 15 is a coupler. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A setting device that outputs an electrical signal calibrated at the test pressure, an electric pressure gauge that outputs an electrical signal in response to the test pressure, and a deviation signal between the setting device output and the electrical pressure gauge output. a servo amplifier to which is input, a servo motor controlled by the output of the servo amplifier, a plunger pump that outputs a discharge pressure that follows the operation of the servo motor, and a pressure booster that outputs a discharge pressure that corresponds to a predetermined air pressure. 1. A pressure gauge testing device comprising: a cylinder, the pressure increasing cylinder output being applied to the plunger pump output via a check valve.