RU2373506C1 - Device for calibration of manometres - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention refers to the sphere of pressure measurements, in particular, for the calibration and standardisation of manometres. The device for calibration of manometres consists of control device, collector for connection of standard instrument and manometres to be calibrated and connected to the tank with liquid and to the device to create the pressure. The device is made in the form of cylinder with plunger kinematically connected by the transfer screw-nit rolling to reduction gearmotor electric motor whereof is equipped with the brake and is electrically connected to the control device. In the pipe between cylinder and tank the back-pressure valve is installed.

EFFECT: simplification of construction of the device during automation of the calibration process.

1 dwg

Description

The invention relates to the field of pressure measurement, namely, verification and calibration of pressure measuring instruments, in particular a pressure gauge.

Known devices for checking manometers, made on the principle of deadweight testers (see PM RF No. 15607, RF patent No. 2219506, RF patent No. 2044291).

In known devices, the reference pressure is set by manual installation of weights and a hand pump, which makes the verification process time-consuming and inefficient.

Among the known devices, the closest in technical essence (prototype) is the "Device for checking pressure gauges" (see RF patent No. 2282166), containing a collector for connecting a pressure sensor and calibrated pressure gauges, a tank with liquid, a device for creating pressure connected by highways to the collector and a tank, and a control device consisting of a computing and control device, indicating and printing units, electrically connected to a pressure sensor and a pressure generating device.

In this device, pressure is generated by a source of compressed air and is converted by means of pneumohydraulic multipliers with different amplification factors, the inputs of which are connected to a source of compressed air through pressure reducing valves, and the outputs are connected to the collector through electrically operated valves.

This scheme of the device for creating pressure is quite complex and time-consuming to implement due to the presence of several multipliers and electrically controlled pressure reducing valves.

The objective of the proposed technical solution is to simplify the design of the device while automating the verification process. The solution to this problem is achieved by the fact that the device for creating pressure is made in the form of a cylinder with a plunger kinematically connected by means of a rolling screw-nut transmission to a gear motor, the electric motor of which is equipped with a brake and is electrically connected to a computer-control device, and in the line between the cylinder and the tank is equipped with a check valve.

The analysis of publicly available sources of information on the prior art did not allow to identify a technical solution identical to the declared one, on the basis of which a conclusion is made about the unknownness of the latter, i.e. on compliance of the decision presented in this application with the criterion of “novelty”.

A comparative analysis of the claimed solution with known technical solutions revealed that the presented set of distinctive features is unknown to a person skilled in the art and does not follow explicitly from the prior art, on the basis of which it is concluded that the solution presented in this application meets the criterion of "inventive step".

The drawing shows a diagram of the proposed device for calibration of pressure gauges. In the diagram, the hydraulic lines are shown by solid lines, the electrical connections by dashed lines.

A device for checking manometers contains a manifold 1 with quick-connects (nipples) 2, by means of which a reference device 3 pressure sensor 3 and calibrated pressure gauges are fixed 4. A fluid tank 5 and a device for creating pressure 6 are connected to the manifold 1 by hydraulic lines. 6 includes a base 7, to which a hydraulic cylinder 8 with a plunger 9 and a gearbox 10 with an electric motor are attached 11. The plunger 9 is connected to the output shaft of the gearbox by transmitting a rolling screw 12 10. The plunger 9 is fixed from turning by a lever with a roller 13. The electric motor 11 is equipped with a brake 14. A check valve 15 is installed in the hydraulic line between the hydraulic cylinder 8 and tank 5.

The control device 16 includes a computing and controlling device 17, an indicating unit 18 and a printing unit 19. The computing and controlling device 17 is electrically connected to a pressure sensor 3 and an electric motor 11.

The device for calibrating manometers works according to the following cycle: increasing the pressure from zero to maximum within the scale of the calibrated manometer, holding the manometer under pressure for a predetermined time, reducing the pressure from maximum to zero.

The verification standards, depending on the accuracy class of the calibrated manometer, regulate the number of calibrated points on the scale of the device, in which the testimony of the reference device (sensor) and the calibrated device (pressure gauge) are compared. By the magnitude of the error, a conclusion is drawn on the suitability of the pressure gauge.

Before starting verification, the calibrated gauges 4 are fixed on the collector 1 by means of quick-detachable connections 2. To increase productivity, several pressure gauges of the same type can be installed. The drawing shows the installation of two pressure gauges.

On the control panel of the computing and control device 1 7, verifiable parameters are entered, for example, a range of indications of a gauge scale, identification numbers of gauges, accuracy class, etc. In accordance with the program embedded in the computing and control device 17, for the specified pressure range, the gauge scale divisions are set in which the numerical values of the pressure are compared by the standard instrument and the calibrated gauge.

When calibrating gauges in the sub-cycle of increasing pressure from zero to maximum, the operator records the readings of the arrows of the calibrated gauges 4 at zero (atmospheric) pressure and stores them in the memory of the computing and control device 17. Then the operator sends a command to start the cycle. In accordance with the selected program, the computing and control device 17 supplies an electric signal to the electric motor 11. The brake 14 opens and the electric motor 11 drives the rolling screw-rolling nut 12 through the gearbox 10. The plunger 9 enters the cylinder 8, which leads to an increase in pressure manifold line 1 to a value corresponding to the first verified point on the scale of the pressure gauge 2. The check valve 15 closes the tank 5 from overpressure. The increase in pressure is controlled by a pressure sensor 3, the actual pressure value is displayed on the display unit 18. When the pressure corresponding to the first point being checked is reached, the electric motor 11 is turned off and braked. The operator visually registers the deviations of the readings of the arrows of the calibrated gauges 4 from the actual value and enters them into the memory of the control device 16, after which it gives a command to continue the verification cycle. Similarly to the described above, the error in the readings of verified pressure gauges is recorded at all points on the scale specified by the program.

Exposure of calibrated pressure gauges to a predetermined maximum pressure for a predetermined time verification process is carried out according to the program when the motor 11 is stopped and braked.

In the process of calibrating pressure gauges with a decrease in pressure from maximum to zero, the task of the pressure values to be verified and the error of the readings are recorded in the reverse order described above.

Based on the results of verification, a protocol is displayed on the print unit 19 for each manometer to be verified, indicating the error at all points required by the test program, and also by comparing with the permissible error in the final part of the protocol, a conclusion is made about the suitability or unsuitability of the manometer.

Thus, the proposed device is quite simple hardware allows you to automate the calibration process of pressure gauges. The compactness of the device makes it possible to use it to create mobile installations that allow testing pressure gauges in the field.

Automating the process of adjusting pressure and recording results can reduce calibration time and reduce the likelihood of errors caused by subjective factors. Gauge calibration protocols are a document objectively confirming the results of certification of a specific gauge.

Claims (1)

A device for calibrating pressure gauges, comprising a collector for connecting a pressure sensor and calibrated pressure gauges, a liquid tank, a pressure generating device connected to the collector and the tank by pipelines, and a control device consisting of a computer-control device, indicating and printing units, and electrically connected to a pressure sensor and a device for creating pressure, characterized in that the device for creating pressure is made in the form of a cylinder with a plunger kinematically connected by means of gears Rolling screw-nut with geared motor, which motor is equipped with a brake and is electrically connected to the evaluating and control device, and in line between the cylinder and the tank check valve.