Method to measure pressure of safety valve opening start

FIELD: machine building.

SUBSTANCE: in the formula P S = P 1 + ( F 1 | F 2 F 1 | ) × ( | P 1 P 2 | ) ; P S = P 2 + ( F 2 | F 2 F 1 | ) × ( | P 1 P 2 | ) ; PS is the pressure of the start of safety valve opening; P1 - pressure in the inner cavity of the safety valve at the first measurement of its pressure of opening start; P2 - pressure in the inner cavity of the safety valve at the second measurement of its pressure of opening start; F1 - force required to open the safety valve at the first measurement of its opening start pressure; F2 - force required to open the safety valve at the second measurement of its opening start pressure.

EFFECT: reduced labour inputs in the determination of pressure of safety valve opening start without the valves' demounting from a pipeline by means of measuring the forces required to open the valves at two different pressures in their inner cavity and by the following calculation of pressure of safety valve opening start.

1 dwg

 

The present invention is intended for measuring pressure since the opening of the safety valves.

In the patent of Russian Federation №82490, IPC G01M 13/00, B66D 3/00 described test rig for breathing and relief valves on tanks with oil or petroleum products and fixture for use, containing an annular flange for mounting the valve at one end of the flange and sealed attach the inlet valve to the Central hole of the flange, compressor-vacuum device for creating pressure or vacuum valve, a device for measuring pressure or vacuum valve, the pipeline.

In the patent SA, IPC G01N 38/00 described device for periodic testing of the safety valve apparatus and vessels, comprising a housing, thrust, drive, capture, dynamometer.

The closest in technical essence of the present invention is a method for testing safety valves described in the patent SL 9600167 And IPC G01L 1/00, G01L 1/04, G01L 7/02, as well as a device for its implementation, containing an electric motor (actuator), a frame, a pressure sensor (a device for measuring pressure), the control module, the gear, the locking head (grip), a device for measuring the force.

This method allows you to measure the pressure at the beginning open the Oia safety valve without dismantling the pipeline, on which they are installed. For measuring pressure since the opening of the device mounted on the housing of the safety valve, the capture device is fixed on the locking element of the valve. After that, the internal cavity pressure relief valve serves the working medium working pressure (Wednesday may already be pre-filed), which in normal mode less pressure since the opening. Then, on the drive serves the electric current. Rotating the drive shaft through the reduction gear compresses the valve spring until, until, is the beginning of the valve opening. The control module records the beginning of the opening or pressure drop in the inner cavity of the valve, or by modifying the efforts of the opening, and then calculates the pressure value since the opening of safety valves for dependencies:

where:

PH- pressure at the beginning of the opening of the safety valve;

F - the force created by the actuator;

S is the effective area of the seat (the area of the seat, which operates the working medium pressure) safety valve;

P is the pressure in the inner cavity of the safety valve.

The value of the effort F generated by the actuator, or calculated by the control module through the value of the current consumed by the actuator is determined either by the device to measure the pressure, associated with the capture device.

In order to accurately determine the pressure at the beginning of the opening of the safety valves must know the value of effective area of their saddles. Often, however, the value of effective area of the saddle is not known. Determining the values of the effective area of the saddle requires dismantling of the safety valve from the pipeline and their subsequent disassembly and measurement of the desired value. This leads to a significant increase in the complexity of determining pressure since the opening of the safety valves.

The proposed method allows to reduce the complexity of determining pressure of the opening of the safety valve without dismantling the pipeline by measuring the effort required to open the valves at two different pressures in their internal cavity and the subsequent calculation of pressure since the opening of the safety valves on the dependencies:

where:

PH- pressure at the beginning of the opening of the safety valve;

P1- pressure in the inner cavity of the safety valve at the first measurement pressure since the opening of;

P2- pressure in the inner cavity of the safety valve when re-measuring its pressure since the opening of;

F1

F2- the force required to open the relief valve when re-measuring its pressure since the opening. The figure presents the device for realization of the proposed method of measuring pressure since the opening of safety valves installed on the relief valve.

The device for implementing the method (see drawing) consists of a frame 1, drive 2, grip 3, a device 4 for measuring the force, the device 5 for measuring the linear displacement, the control module 6, unit 9 for measuring pressure. The control module 6 reads the signals from the device 4 for measuring the force, the device 5 for measuring the linear displacement device 9 for measuring pressure and by means of the control program controls the actuator 2. In addition, the control module 6 outputs the value of the pressure since the opening of the safety valves on the internal display or other display device information (in the drawing not shown). In the figure a relief valve installed on the pipe 10.

Pressure at the beginning of the opening of the safety valves is measured as follows. The device for implementing the method stipulated in the up frame 1 on the relief valve 7, while the grip 3 and the device 5 for measuring the linear displacement is fixed on the locking element 8. The control module 6 issues a command to the actuator 2, which creates a force to move the locking element 8. At that moment, when the actuator generates a force sufficient to open the relief valve 7, the locking element 8 begins to move. The device 5 for measuring the linear displacement captures the moment of the beginning of movement of the locking element 8, and the control module 6 fixes the maximum force generated by the actuator 2. The device 9 pressure measurement fixes the maximum pressure in the inner cavity of the safety valve 7. After that, the pressure in the inner cavity of the safety valve 7 change. Similarly, the control module 6 re-fixes the maximum force generated by the actuator 2. Further, the control module 6, having the values of all source data, calculates the pressure at the beginning of the opening of the safety valve 7 for dependencies (2). Calculating the required pressure at the beginning of the opening of the relief valve 7, all the elements of the device command module 6 control is returned to the original state.

The complexity of determining the value of pressure since the opening of the safety valves on the proposed method was reduced seven times.

Application offer aemula way of measuring pressure since the opening of safety valves ensures the achievement of the technical result a reduction of the complexity of determining pressure since the opening of the safety valves.

A method of measuring pressure since the opening of the safety valve without dismantling the pipeline by measuring the force required to open the valve, pressure in the inner cavity of the valve and then calculating the desired value of pressure since the opening of safety valves by measuring the force required to open the valve, characterized in that the pressure measurement since the opening of the safety valves is carried out by measuring the effort required to open the valves at two different pressures in their internal cavity and the subsequent calculation of pressure since the opening of the safety valves on the dependencies:


where:
PH- pressure at the beginning of the opening of the safety valve;
P1- pressure in the inner cavity of the safety valve at the first measurement pressure since the opening of;
P2- pressure in the inner cavity of the safety valve when re-measuring its pressure since the opening of;
F1- the force required to open the relief valve when the first measurement of pressure since the opening of;
F2- the force is required to open the relief valve when re-measuring its pressure since the opening.



 

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