SU1326926A1 - Apparatus for calibrating pressure transducers - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to expand the field of application of the device and increase accuracy. The device contains a source of compressed gas 1, pneumatic routes 2 and 13, adjustable gear 3 with control cavities 3 and 3, throttle 4, shut-off valves 5 and 12 with electromagnets 5, 12, pipe 6 with nozzles 7, converters 8 to 9, choke 10 with a reducer 11, pressure alarms 15 and 16, a control panel 17, a pressure meter 18, a step finder 20, a toggle switch 33 and a relay of the signal acquisition and recording system 30. The introduction of new elements and the formation of new connections between the elements of the device automates the process of calibrating converters 8 and 9 and expand the field of application of the device by covering a large number of recording automated systems with intermediate carrier and systems created on the basis of non-controlling EBMs., 2 ill. with "in (L 18 J3 th J-. Y: about N3 35 G)

Description

The invention relates to instrumentation technology, in particular to instruments for the calibration and metrological certification of primary pressure and vacuum transducers.

The purpose of the invention is to expand the field of application and increase the accuracy of the device.

Fig. 1 shows the principle, aln diagram of the proposed device; Fig. 2 is an electrical circuit of the control unit;

The device contains a source of compressed gas 1, a pneumatic route 2, on which an adjustable gear 3 is installed with control cavities 3 and 3, cavity C is connected to pneumatic line 2 between gear 3 and throttle 4, and cavity C is connected to the internal cavity of pipe 6 , throttle 4 inlet shut-off valve 5 with electromagnet h, pipe 6 with fittings 7 placed on it for installing graduated 8 and exemplary 9 primary pressure transducers (dilution), throttle 10, adjustable output gear 11 with control cavities 11 and 11, cavity 1 l connected to the pneumatic rail 13 before, and the cavity 11 behind the choke 10, the shut-off valve 12 with the electromagnet 12 and the perforated cylinder 14 installed coaxially inside the pipe 6 at the outlet of the pneumatic track 2 behind the inlet shut-off valve 5 and at the entrance to the pneumatic track 13,

The pressure detectors 15 and 16, connected to the cavity of the pipe 6, with their contacts, respectively, through intermediate relays RGP 22 and RP2 23 open and close the shut-off valves 5 and 12 of the control panel 17, on the front panel of which there is a test gauge 18 of pressure in the source 1 of compressed gas, a start button 19, a step finder 20 for setting up a poll and a position switch 21. Inside the control console 17, intermediate RP1 22, RP2 23, RPZ 24, RP4 25 and RP 26 relays are installed, RP relay ( ROC 1 28 measurement cycle Eni, the relay 29 is turned off, the relay of the signal acquisition and recording system 30, coming in from the primary transducers 8 and 9. in which there is a contact K31, provides

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0

five

0

five

0

five

0

five

stopping the inclusion of an intermediate relay .27, a harness 32, providing communication for the control panel 17 and the signal collection and recording system 30.N.CLOV, a toggle switch 33, which ensures the condition of operation with an unmanaged I or a control II computer.

The device works as follows

Graduated 8 and exemplary 9 pressure transducers (dilution) are connected to fittings 7, depending on the required dynamic error, the time of filling and emptying the pipe 6 is selected by selecting the cross section of the throttles 4 and 10 and the differential pressure on them, as well as setting gearboxes 3 and 11 The pressure alarms 15 and 16 are adjusted over the range or adjusted to the required pressure. The pressure transducers 8 and 9 are connected to the system for collecting and recording parameters.

Prepare the calibration system for operation by setting the required pressure at the source 1 of compressed gas, controlling it by measuring 18 pressure, the number of polling cycles with the help of the step finder 20, and carrying out the necessary work to prepare the information collection and recording system 30. Then switch the toggle switch 33 to position I.

At the end of the preparatory work, the button 19 is pressed, which turns on the industrial switch; the daily relay 26, which blocks the button 19 with its contacts, turns on the primary pressure transducer interrogation system (zeros) and prepares the turn-on circuit of the step finder 2Q. (DPC) and remove their zero readings. Contact K 31 switches on an intermediate relay 27, which blocks itself and turns on the intermediate relay RP2 23, switching it to the operating position, as a result of which the electronic romagnet 3 cut-off valve 5, opening it, c. As a result, the volume bounded by pipe 6 will be filled with gas, and the pressure in the pipe will increase at a rate corresponding to a constant pressure drop across the throttle 4 supported by the gearbox 3. The signals from the primary converters

3

8 and 9 will be registered by the system. 30 data collection and recording. When the maximum pressure, controlled by the pressure indicator 15, is reached, its contacts will close, resulting in an intermediate relay RP1 22, which will turn off the solenoid 5 of the shut-off valve 5 and turn on the solenoid 12 of the shut-off valve 12, as a result of which the pressure in the pipe 6 will decrease speed, as in the first case, corresponding to the constant differential on the throttle. 10, maintained by the gearbox 11. When the minimum pressure is reached, the pressure alarm 16 will operate, which, through the intermediate relay 23, will command to close the shut-off valve 12 and open the shut-off valve 5 and the measurement cycle will be repeated as many times as specified on the step switch 20.

Upon reaching the established measurement cycles, the step switch 20 turns on the intermediate relay 29, which turns off the entire calibration system.

When calibrating the primary vacuum transducers, an evacuation system is connected to the outlet of the shut-off valve 12, and the source of compressed gas is communicated with the atmosphere, and the calibration process is carried out in the same sequence.

Information is collected from the primary transducers 8 and 9 in the following sequence: the readings are recorded first from the reference and then from the calibrated primary transducers and again from the reference.

The true pressure value for each calibrated primary transducer is determined by the dependence

(A - A,)

P

 d

de A.

A, A „; .-amplitude for i-ro converter;

the amplitude recorded by the reference transducer, prior to recording the pressure values of the graduated transducers;

amplitude after recording the pressure of the calibrated transducers;

, n is the number of primary converters;

i index and place of the calibrated transducer. The calibration is repeated as many times as necessary depending on the methodology, then the results are processed and presented in the form of polynomials or tables indicating the deviation errors from the standard means and are used later in deciphering the readings of the primary transducers installed on the test objects.

When using control computers, the toggle switch 32 switches to position II and the signals come from intermediate relays PC computer 1 or PC computer 2 (the diagram shows only contacts), whose contacts open or close shut-off valves 5 or 12.

The use of the proposed device makes it possible to automate the calibration process of primary transducers or pressure measurement channels in automated systems, expand the scope of the calibration device by covering a large number of recording automated systems with intermediate media and automated systems based on non-controlling computers, and improve the accuracy of the calibration.

Claims (1)

Invention Formula A device for calibrating pressure sensors, containing a source of compressed air, connected by a pneumatic route to a pipe, on which are placed fittings for connecting graduated and exemplary pressure transmitters and in which a perforated cylinder is coaxially mounted, and the first shut-off valve is located at the inlet of the pipe electrically operated and input choke and outlet A 50-out pipe is an output choke and a second electrically operated cut-off valve, characterized in that, in order to expand the field of application and increase accuracy, 55 also has the ability to control the build-up and depressure cycles,; In front of the inlet throttle, there is a first adjustable pressure reducer, the control cavities of which are connected — one to the pneumatic rail before the inlet throttle and the other to the cavity of the pipe; a second adjustable pressure reducer is installed, the control cavities of which are respectively connected to the pneumatic route to and behind the outlet choke, and  27п-ОТ 7 The internal cavity of the pipe is connected to pressure sensors, the contacts of which through the contacts of the intermediate relays are connected to the electric drives of the shut-off valves, and the first shut-off valve is installed in the pneumatic route between the outlet throttle and the pipe inlet. Rpotk pn U 1 U U 1 RPTs. 0.9. Rpotk -ft RP WP2 tt Repot 11 RPts.O. Rppi II11 FIG. 2  2208 J | i | to-3 / -27 Pock -ft v " Rance - J RPts.O.Z / 7/7/22 four:: min. S, Sbf l IL RPEVM1 JL WP2 11 2 tt mouth Rppi eleven and about S ir.: g: s Wftf 25 -P .20 RLts.i23 VNIIPI Order 3272/36 Circulation 776 Subscription Proizv.-poly. pr-tie, Uzhgorod, st. Project, 4