SU845030A2 - Device for automatic setting and maintaining pressure - Google Patents

Description

(54) DEVICE FOR ABTO / VLATHHECKOrO TASKS AND SUPPORT PRESSURE

one

The invention relates to the field of instrumentation, in particular to devices for testing and testing pressure sensors.

According to the main author. St. No. 418834, a device for automatically setting and maintaining pressure, comprising a piston pressure gauge, a vessel with separation fluid, an outlet choke, solenoid valves, a differential piston rigidly connected to a sensitive element of a capacitive sensor and a compensating coil mounted in a permanent magnet field, is an additional sub-piston. the cavity of which is connected by pipelines with the cavity of the bellows, the cavity of the damper and the piston, the software device connected to the pressure unit, the roar unit XRD consisting of pressure circuits, and the memory unit, the inverter amplifier, a control unit and a motor pneumosizes 1.

To set a predetermined pressure in such a device, a vent valve and a blower for pneumatic capacity are used. It does not provide a smooth adjustment of a given pressure value and affects

on the duration of the transient processes that occur when setting the specified pressure.

The aim of the invention is to increase plant capacity and. sensor calibration accuracy.

This is achieved by installing in the device for automatic setting and maintaining pressure parallel to the main valves one additional valve, the windings of electromagnets of which are connected to the output of the key circuit, one of the outputs of which is connected to the output of the control unit and the other of the amplitude discriminator whose input is connected to the unbalance sensor output.

The drawing shows constructive 15 on the scheme of the proposed device.

The device contains a pressure gauge 1, a vessel 2 with a separation fluid, the outlet fitting 3, the main solenoid valves 4 and 5, the differential piston 6,

Claims (1)

20 rigidly connected to the sensitive element 7 of the capacitive sensor 8 and the compensation coil 9 placed in the field of the permanent magnet 10, an additional podporshnevaya cavity 11 of which is connected by pipelines 12 to the bellows cavity 13, the cavity 14 of the damper and the piston 15, software 16, connected to the setpoint device 17, the reverse unit 18, consisting of the comparison circuit 19 and the memory block 20, the converter-amplifier 21, the control unit 22, the electric motor 23, the pneumatic capacitance 24, the amplitude discriminator 25, the key circuit 26 and additional elec tromagnetic valves 27 and 28. The amplitude discriminator 25 is a threshold circuit, the output signal which occurs when excess signal at the input of a set value. The signal from the output of the amplitude discriminator 25, the key circuit 26 connects the electromagnets of the valves 27 and 28 to the outputs of the control unit 22. The device operates as follows. According to the signals from the software device. 16, the valve 4 opens and the bellows 13 exposes the pistons 15 of the damper and the manometer to the initial state corresponding to the zero value of the signal from the sensing element 7 of the sensor 8. The weight of the differential piston is balanced by the weight of the piston 15 of the damper. The pressure is set in accordance with the program of the device 16. The pressure setter 17 outputs to the memory unit 20 a setpoint value corresponding to a predetermined pressure. In this case, the converter-amplifier 21 sets a current in the compensation winding that is sufficient to balance the specified distance. Due to the fact that at the time of issuing the setpoint, the pressure under the piston 6 does not correspond to the specified value, the sensitive element of the sensor 8 is displaced from the middle position and the output of the sensor 8 has an imbalance signal, the value of which exceeds the pickup threshold of the amplitude discriminator 25. As a result, the output, a signal appears which, through the key circuit 26, connects the electromagnets of the valves 27 and 28 to the outputs of the control unit 22. The comparison circuit 19 outputs to the control unit 22 signals opening the valves blowers 5 and 28, if the setpoint requires a pressure increase, or opening relief valves 4 and 27, if the setpoint requires a pressure drop. As the pressure value below the threshold 6 approaches the preset level, the signal from the imbalance sensor 8 begins to decrease, approaching a zero value. When the signal from the sensor 8 decreases below the threshold of the amplitude discriminator 25, the output signal disappears and the key circuit 26 turns off the additional valves 27 and 28 from the output of the control unit 22, and further charging (reset) occurs only through the main valves 4 and 5. At the same time, the rate of change of pressure at the outlet fitting 3 becomes smaller, which ensures a smooth approach to a given pressure. When the imbalance signal becomes zero, the control unit 22 generates a signal for closing valves 4 and 5. The bellows press aligns and automatically maintains the set pressure. The use of the invention makes it possible to increase the smoothness of the installation of given levels of pressure and temp. To shorten the calibration time. The invention The device for automatically setting and maintaining pressure on the author. St. No. 41-8834, characterized in that, in order to increase device performance and sensor calibration accuracy, two additional valves, an amplitude discriminator and a key diagram are inserted, each valve is installed parallel to the main corresponding valve, the solenoid windings of additional valves the output of the key circuit, one of the inputs of which is connected with the output of the control unit, and the other with the output of the amplitude discriminator, the input of which is connected to the output of the capacitive sensor. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 418834, cl. G 01 L 27/00, 1977.