SU1420407A1 - Thermoelectric pressure transducer - Google Patents

Abstract

The invention relates to vacuum manometry and permits an increase in accuracy and stability under conditions of a change in the spatial orientation of a device. A spherical frame 6 made of an insulating material is fixed on the current-carrying posts 3, 4. On the surface of the frame 6 between the diametrically opposite points of attachment, there is a spiral groove 5 with a constant pitch, in which the heat-sensitive thread 2 of the temperature-sensitive element is laid. With a change in the measured pressure, the resistance of the filament 2 changes, which leads to the imbalance of the bridge measuring circuit into which the pressure transducer is connected. 1 il. te (L oo o o o

Description

The invention relates to vacuum manometry, in particular to heat-electric vacuum gauges, and can be used to measure the pressure of a rarefied gas in vacuum installations for various purposes.

The purpose of the invention is to improve the accuracy and stability in terms of changing the spatial orientation of the transducer.

: The drawing shows the design of the 1 | and pressure transmitter. The converter includes a housing 1 inside of which, on the current leads 3 and 4, a temperature-sensitive element is fixed, made in the form of a thread 2, laid in an annular spiral groove 5, having a constant step along the spherical framework 6, made of current-conducting material jja, for example, fluoroplast, and mounted on the current leads 3, 4. The converter operates as follows.

; With increasing or decreasing pressure in the converter case, the number of gas molecules that are involved in heat exchange increases or decreases (respectively). A: So, if the number of gas molecules decreases (due to a decrease in pressure), the heat transfer from the thermistor filament decreases, the filament heating temperature increases, hence the filament resistance increases. Since the transducer is included in a bridge measuring circuit, as the pressure changes, an imbalance occurs in the circuit, which is a function of pressure. The converter works in the same way with increasing pressure. Due to the proposed configuration, the heat flux does not change at different orientations of the converter in space.

It is known that the amount of heat given off by convection heat transfer depends on the angle of inclination of the surface and is maximum when compiled I. Editor A.Dolinich Tehred I.Veres

its zonal position. The amount of heat is determined by

    H-so- (sinci).

where q s

T

heat flux density; effective heat transfer area;

SQ is the thermistor area; oi is the angle between the longitudinal axis of the thermistor and the normal. In the proposed design, the effective heat transfer area S c not

20 25

J5 depends on the angle ei. since s

u

0 5

0

five

0

five

the area of the orthogonal projection of the ball.

Since the effective area of the thermistor output does not change with a change in the angle of inclination, the heat flux remains constant with an arbitrary spatial orientation of the converter, thereby increasing accuracy and stability.

The application of the invention makes it possible to obtain a positive effect, concluded in increasing the accuracy and stability of the converter in terms of its arbitrarily varying spatial orientation.

Claims (1)

Invention Formula A thermoelectric pressure transducer, containing a housing, in which a thermosensitive thread is placed, is connected to two current-supporting racks, characterized in that, in order to increase the accuracy and stability in terms of a change in the spatial orientation of the transducer, a spherical the frame of insulating material, which is fixed on the current-carrying racks, in two diametrically opposite points, and on its surface between the attachment points there is a spiral groove with a constant groove th, the thermally responsive thread is laid into a helical groove, a step which is greater than the filament diameter. Proofreader M.Maksimishinets