SU1223149A2 - Controlled jet hot-wire anemometer - Google Patents

Abstract

The invention relates to a measuring technique and allows one to expand the informative capabilities of the device by measuring the dynamic pressure of the gas stream. The gas jet formed by the choke 1 blows over the thermal sensor 2. The vibrator 4 excites gas oscillations in the cavity of the housing 3, the amplitude of which is changed by the regulator 5. These oscillations lead to the formation of a jet directed to the screen 9, to which the jet from the dynamic pressure receiver 8, the outlet of which is located in the wave node on the same axis as the throttle 1. The total receiver length is a multiple of half the wavelength of the operating frequency of the vibrator. Pipe 7 serves to connect to a source of static pressure and to equalize the static pressure in the measured flow and in the cavity of the thermal sensor. The invention is an improvement on the main author. No. 537301. 1 Il. § hO its X) 4; o

Description

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The invention relates to a measuring technique and can be used as a gauge of dynamic pressures in gas flows.

The purpose of the invention is the expansion of informative possibilities by measuring the dynamic pressure of the gas stream.

The drawing shows a diagram of the device.

The device consists of throttles 1, designed to form a gas jet blowing a thermal sensor 2, which is installed inside the thermal sensor case 3, the oscillations of gas (air) in the cavity of the housing c. Are excited by the vibrator 4, and their amplitude is changed by the regulator 5, the power the sensor is carried out through the current-carrying conductors 6, on the case of the sensor 3 there is a pipe 7 which serves to connect to the source of static pressure in the measured flow and to equalize the static pressure in the measured flow and D cavity and a temperature sensor, or for correcting the frequency characteristics of a controlled jet thermal anemometer, the dynamic pressure receiver 8 is hermetically inserted into the thermal sensor body and its outlet opening is directed toward the screen 9, made in the form of a tube, the dynamic pressure receiver and throttle located symmetrically relative to the screen and positioned a thermal sensor on the same axis with it, the total length of the dynamic pressure receiver is a multiple of half the wave of the vibrator's operating frequency, and the outer edge of the receiver is Our pressures are located at its site.

The principle of measuring the dynamic pressure in a flow is based on comparing its value with the known pressure developed on the throttle due to the operation of the vibrator. In this case, the operating frequency of the vibrator determines the working wavelength.

The absence of multiplicity half the wavelength of the operating frequency of the vibrator and the length of the dynamic pressure receiver leads to a pressure difference at the ends of the dynamic pressure receiver and to the appearance of air currents inside it, which distorts the measurement results of dynamic

pressure in the gas (air) flow,

The device works as follows

The vibrator 4 creates inside the body of the thermal sensor 3 variable oscillations of the gas (air), which leads to the formation of a jet on the throttle 1, the required velocity of the jet is set by the amplitude regulator 5, and the jet itself is directed to the screen 9, inside which the thermal sensor 2 is sensitive to the magnitude of the speed, on the other hand this

the screen 9 from the receiver 8 dynamic pressure, placed in the measured gas flow, jet expires due to its dynamic pressure,

In the screen 9, these two jets at the moment of their equality, which is carried out by the amplitude regulator 5, create a zero gas flow rate, which is registered by the thermal converter

2, the signal from which along the current-carrying conductors 6 is fed to the electronic circuit of the indicator; logging 7 is connected to the measured flow to equalize the static

pressure, either by means of external pneumatic i-chains, or connected to the throttle to correct frequency characteristics. The initial calibration for dynamic pressures is carried out on standard calibration devices.

The use of the proposed device as a dyn meter

The mechanical pressures in gas flows expand the informative capabilities of the main device.

Claims (1)

Invention Formula Managed jet thermo-anemometer according to avtom, sv, P 537301, characterized in that, in order to expand the informative possibilities by measuring the dynamic pressure of the gas flow, it is equipped with a dynamic pressure receiver and a screen made in the form of a tube and spaced inside the housing coaxially to the throttle In this case, the dynamic pressure receiver is partially located inside the housing so that its outlet opening is on the same axis with the rosel on the other side of the screen. 312231494 and a temperature sensor is installed inside the screen half of the wavelength of the working tank, the total receiver length of the vibrator's receiver, and its output pressure output is performed at the wave node.