SU1000811A1 - Rarefaction pickup dynamic graduation device (its versions) - Google Patents

Description

The invention relates to appliance building, in particular, to devices for calibrating a vacuum sensor.

A device for dynamic calibration of a pressure sensor is known, comprising a cylinder with a piston and a drive of the piston 1.

The known device does not provide calibration of the vacuum sensors in a wide range.

The closest in technical essence and the achieved result. The proposed device is a device for dynamic calibration, containing a pressure source,. a duct with a nozzle and a pipe 2.

The known device also does not allow to obtain pressure fluctuations in a wide frequency range.

The purpose of the invention is to expand the range of calibration.

The goal is achieved by the fact that in a device for dynamic calibration of vacuum sensors containing a pressure source connected by a gas duct to a nozzle and a pipe, Sorlo is located inside the pipe, coaxially, graduated sensors are installed in the wall of the pipe, in the plane of the cut of the oil, and the gas pipe is put on the movable ring with seals associated with the drive, while the cross-section of the pipe is made according to the ratio

 cr 2-1- (0.08 Md + b,

where R., „the area of the critical section 10

cr no nozzle 5. Mach number at cut-off with a cond jf P „gas pressure at the nozzle inlet, referred to atmospheric. To obtain pressure pulses

pipe cross section is made

by the ratio B

20

FTP RRC 2nd (o, 042m2-0,, 5)

The drawing shows a device for dynamically calibrating the sensors of rarefaction, a general view of e.

25

The device for dynamic calibration of the vacuum sensors contains a source of compressed gas 1, connected by a duct 2 to the nozzle. Laved 3, the Mach number on the cut of which

Claims (2)

30 is greater than or equal to one. As a source of compressed gas 1, a powder or air pressure accumulator can be used. The nozzle Lawal 3 is installed coaxially in the pipe 4 with a zero ejection coefficient. A cylinder 5 is attached to the pipe 4 in the asoplou region A by means of a piston 6 installed in it, forming the cavity B of an adjustable volume and driven, for example, in the form of a screw pair, the role of the movable element of which is performed by the nut 7 moving during the rotation of the external duct of the duct 2. When the nut 7 is rotated, the handle 8 transmits the reciprocating movement of the nut 7 through the tubular rod 9 to the piston 6, the displacement of which causes a change in the volume of the cavity B. In the area of the output section of the Laval nozzle 3, in the same plane of the cross section of the pipe 4, sockets are installed in which calibrated 10 and reference 11 sensors are installed. The device works as follows. The gas flow from the Laval nozzle 3 expands in pipe 4 in the mode of unstable alternate attachment of subsonic and supersonic sections to pipe 4, due to which intense pressure oscillations occur in the backhole region A of pipe 4, which are recorded by reference reference 11 and calibrated by 10 sensors. The oscillatory process is realized only with well-defined relations between the gas-dynamic and geometric parameters, expressed by the dependence — p; .24o, 08M.V) where n. P, is the total pressure of the gas by the nozzle corresponding to the beginning of the flow rate-switching mode, referred to the value of the external pressure Ru; o - / - l, a ° a {LCHr - total gas pressure before, the nozzle corresponding to the end of the oscillatory flow mode, referred to the external pressure P .. Claim 1. Device for dynamic calibration of vacuum sensors containing a pressure source connected by a duct with a nozzle, and a pipe, excellent. In order to expand the graduation range, the nozzle is located inside the pipe, coaxially, the calibrated sensors are installed in the pipe wall, in the plane of the nozzle section, and the gas ring is equipped with a movable ring with seals associated with the drive, while the cross section the pipes are made according to the ratio 2- | - (o, dmd + 3, 1; where Fp is the critical section area of the nozzle, Md is the Mach number at the nozzle section, P (, is the gas pressure at the nozzle entrance, referred to the atmospheric sphere. 2 A device for dynamic sealing of vacuum sensors, containing an A pressure point connected by a duct to a nozzle, and a pipe, characterized in that, in order to obtain pressure pulses, the nozzle is located inside the pipe, coaxially, calibrated sensors are installed in the pipe wall, in the plane of the nozzle section, and In this case, the cross section of the pipe is connected with the intake of the pipe; the relationship P (o, 042M –C35GD41.5) is the critical section area of the nozzle; the Mach number at the nozzle section PO is the gas pressure at the inlet to the nozzle related to atmospheric pressure. Sources of information taken into account in the examination 1. The author's certificate of the USSR 502264, cl. G, 01 L, 27/00, 1974. 2. Authors certificate of the USSR 200830, cl. d, 01 L 27/00, .1966 (prototype).