SU855416A1 - Electric contact pickup for determining elastic sensing element characteristics - Google Patents

Description

; A 1-pin contact 5. On the measuring IIITOKO 4, located inside the base of the body, a clip 6 is attached with a spring 7 and a pin 8, which moves in the groove of the base and prevents the rod from turning. The upper and lower parts are connected by an insulated sleeve 9. A friction clutch 10 is pressed into the sleeve 9, the second end of which is connected to the sleeve 11. A push rod 12 is installed in the sleeve 11, in which the cap 13 is screwed. The push rod 12 and the cap 13 are preloaded with spring 14.

A threaded sleeve 15 is attached to the friction casing 10, inside which a ball 16 and a spring 17 are mounted. The ball 16 rests on the sleeve 18 of the friction mechanism. The tension of spring 17 is adjusted by screw 19.

The friction mechanism (Fig. 2) consists of a sleeve 18, in which an adjusting screw 20 is screwed on one side, a washer 21, a spring 22 and a washer 23 are mounted on the other side, and a threaded sleeve 24 is tightened against the stop. In the sleeve 24 a contact rod 25 is installed containing pin 26. A groove is made in the sleeve 24 to move the pin 26 in the longitudinal direction and prevent the contact rod 25 from turning. The contact rod 25 is pressed in the sleeve 24 by a spring 27, the second end of which rests through the clamp 28 into the nut 29. Between the adjusting screw 20 andontaktnym rod 25 b is formed working gap, which value is set when adjusting the adjusting screw 20. In the lower portion of the contact rod 25 is an electrical contact 30.

The base of the housing 1 is closed by a cover 31 on which the current supply 32 is located. The current supply 33 from the second electrical contact is mounted on the threaded sleeve 15.

The sensor is installed in the stand 34. The design of the stand is determined by the design of the receiving unit of the device under investigation.

The sensor allows you to determine the four main characteristics of the instruments pressure: sensitivity, proportionality, temperature tolerance and stability.

His work is as follows.

A sensor with a stand is installed on the receiving unit of the device under study. The rod 4 is mounted on the center of the sensitive element (the rigid center of the membrane, membrane box, bellows block). An electrical circuit is connected to the current leads 32 and 33 containing a power source and a signaling device. By lightly pressing the cap 13, the friction mechanism is moved up to the stop, while the contacts 5 and 30 are closed.

When determining sensitivity and proportionality, a pressure equal to half of the nominal

(0.5Р „). In this case, the measuring rod, moving up, moves the friction mechanism.

The pressure is released, at the same time, under the action of the spring 7, the measuring brush returns to its original position and, under pressure P, (Fig. 3) opens contacts 5 and 30. The friction mechanism is kept in the upper position by the action of friction force created by the force of the spring-loaded ball 16.

The sensitivity of the characteristic is determined by the formula

s. y | r, -r, stpm / kgf / cmcha)

In a similar way, the sensitivity of the second half of the characteristic is determined at 1 hs, 1 h Rc,

Si - p 5T- MK / srC / Cn

From where proportionality is calculated by the form. T, fr, .14

 -

When determining the stability and temperature variability of the test site, the receiving receiving unit supplies the overload pressure Pnr (the pressure at which the sensitive element rests on the stop). When the pressure is released, the contacts are closed at a pressure of PZ (Fig. 4).

Test: New devices are stabilized at different temperatures, for example, -. - 150С and others. After holding them under normal conditions, a sensor is installed at the receiver nodes and pressure is supplied to the RP. When pressure is released, pressure P is recorded. Hence the stability of the characteristics is determined by formula (4)

PH

l |

If the pressure measurements P and P are made at different temperatures, then the temperature error of the receiving unit of the tested device is determined by the formula (4).

Since all measurements are determined by the size of the specified gap b, then the accuracy and measurements throughout the entire work and under different temperature conditions is determined by the accuracy of maintaining the constancy of this gap.

In the proposed design of the electrocontact sensor, this is ensured by the following solutions: the working gap is made in the friction mechanism and does not depend on the change in the lengths of the body parts; the rod 25 together with the adjusting screw m. 20 and the gap b forms a closed circuit. Erased / ken 25. The adjusting screw 20 and the bushing 18 are discharged (}. Made of material with the same temperature coefficient of linear expansion; repeated removal and its installation on the tested device.

The size of the working gap is selected commensurate with the stroke of the sensitive element of the test instrument. The surface of the adjusting screw 20 and the contact rod 25, forming a gap b, hardened and polished. Pin 26 and the surface of the threaded bushing 24 against which pin ирает rests | also hardened and polished.

Claims (2)

1. The copyright certificate SGGR No. 606095, cl. G 01 B 7/02, 1976, 2. Author's testimony; R No. 353133, cl. G 01 B 7/16, 19GVI -1 |. From.) TNP). 13 t 12 1 Rig.2 N mm s corrsi Pi Pr R - " HrCt (.