DE3216613A1 - Calorimetric-electronic measuring system for measuring waste gas velocities - Google Patents

Abstract

The measuring system described can be used to measure waste gas velocities both at high temperatures and at low flow rates - in particular in the relevant range from 0.5 m/s to 20 m/s. The measured data supplied by the calorimetric sensor are fed to an electronic computer which determines the analogue value of the speed. The calorimetric sensor consists of a measuring tube through which water flows and which has a temperature sensor in a measuring duct and a compound piping piece with two temperature sensors in the flow and return direction and a water flow meter.

Description

Title: Calorimetric-electronic measuring system

for measuring exhaust gas velocities.

Field of application: The invention relates to a measuring system for detection of exhaust velocities in chimneys and exhaust gas ducts.

Purpose: The measuring system is intended to determine the exhaust gas velocity enable both high temperatures and low currents.

State of the art: There are various measuring principles for measuring exhaust gas velocities to be able to measure.

Mention should be made here of the vane anemometer, the Pitot tube manometer and ultrasonic probes.

Criticism of the state of the art: All of these measuring systems listed here either cannot be used in a high temperature range (e.g. 900 OC) or are Unsuitable for measuring low flows (e.g. 0.5 m / s) or require one corresponding effort and are therefore not suitable for mobile measurements.

Task: The invention is based on the task for the rough To create a working conditions in flue gas ducts for a reliably working measuring system, that delivers reproducible values and is suitable for mobile measurements.

Solution: According to the invention, this object is achieved by a calorimetric Measurement system in connection with an electronic measurement data acquisition and processing solved.

The heat flow acting on a measuring tube located in the exhaust gas flow, causes a temperature difference in the flow of test water. Simultaneously the measured values for the amount of water and the exhaust gas temperature are sent to a computer, which calculates the analog value of the exhaust gas velocity.

To improve the calculated value, you can use the gas composition and the design of the exhaust duct / correction parameters can be entered.

Further embodiment of the invention: In order to improve the adaptability of the To improve the measuring sensor, the actual measuring tube located in the flue gas flow becomes provided with screw connections and is therefore easily exchangeable.

The measuring tube is normally designed in the shape of a hairpin. That However, the flow profile of the flue gas duct can also have other designs of the measuring tube make necessary. An intermediate-insulated double pipe is suitable for measuring in narrow channels; a ring-shaped measuring tube measures the flow distribution better in a round duct cross-section.

The temperature sensor for recording the temperature difference in the amount of water in the morning are installed in the axial direction of the flow and return to the point at the To be able to lay the edge of the exhaust duct.

For mobile measurements it is favorable if the conditions of use of the sensor are as similar as possible to laboratory conditions. Therefore can for this Measurements a precisely defined radiation shielding improve the measurement accuracy. Therefore According to the invention, a metal channel, as a radiation shield, is at a fixed distance un the measuring tube attached. The radiation shield is on the measuring tube remote side thermally insulated.

Achievable Advantages: The advantages achieved with the invention exist especially because of the easy-to-use, insensitive measuring probe reproducible values can be achieved by means of the downstream electronics both at low and at high exhaust gas temperatures in the relevant measuring range ensure reliable measured values from 0.5 m / s to 20 m / s.

Description of exemplary embodiments: Some exemplary embodiments are shown in the drawing and are described in more detail below: Fig.l ... calorimetric-electronic measuring system, mounted on a chimney.

System structure: On the pipe connection piece (1), with front (2) and Return (3), the measuring tube (4) is screwed. The ones built in the axial direction Temperature sensors (5), (6) with their measuring points up to the vicinity of the exhaust gas duct preferred to avoid falsification of measured values due to heat conduction. The conduit connector is thermally insulated up to the white tube.

Further system components are the temperature sensor (7) with its own measuring point in the exhaust gas flow, the one in the flow Water meter (8) and the electronic computer (9) to which the measurement data are forwarded for evaluation will. The metal channel (10) arranged at a fixed distance around the measuring tube, reduces the radiation effect of the channel wall and is on the, the measuring tube remote side thermally insulated to the effect on the measuring tube as possible to keep it low.

Fig.2 ... shows the embodiment of a double tube measuring tube.

In the outer tube (11), which is closed at the end, lies in a coaxial manner Arrangement of the inner tube (12), with an open face and intermediate insulation (13). The screw connections (14), (15) are pulled out to the side.

Fig.3 ... shows the embodiment of an annular measuring tube (16), with the parallel threaded connection fittings (17), (18).

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Claims (1)

Patent claims generic term: calorimetric - electronic measuring system for measuring flue gas velocities in chimneys and flue gas ducts. Characteristic part: characterized in that for implementation the measurement a calorimetric sensor is required, its in the flue gas flow lying parts a hairpin-shaped measuring tube through which water flows and a temperature sensor are, but its component located outside of the flue gas flow is a thermally insulated one The pipe connecting piece is, in addition to two built-in sensors for measuring the Temperature difference of the test water volume, a water volume meter built into the flow contains, and an electronic calculator, which the analog value of the gas velocity, from the measurement data supplied to it by the sensor. Preamble of the dependent claim: 2. Calorimetric - electronic Measuring system according to claim 1, characterizing part of the dependent claim: characterized in, that the hairpin-shaped measuring tube has a detachable screw connection to the pipe connection piece and that the two temperature sensors installed there in the axial direction of the and rewind are built in so that the measuring point of these sensors is as close as possible far, up to the level of the inner wall of the duct. Preamble of the dependent claim: 3. Calorimetric - electronic Measuring system according to claim 1, characterizing part of the dependent claim: characterized in, that the measuring tube is designed as a double-tube measuring tube. In the face closed outer tube, the inner tube is in a coaxial arrangement, with open face and intermediate insulation on the pipe wall. The screw connections are pulled out to the side to match the pipe socket. Preamble of the dependent claim: 4. Calorimetric - electronic Measuring system according to claim 1, characterizing part of the dependent claim: characterized in, because the design of the measuring tube is ring-shaped. The one on the screw connections open curved ring, is made via parallel connecting pipelines, by means of Screw connections, connected with cem pipe connection piece. Preamble of the dependent claim: 5. Calorimetric - electronic Measuring system according to claim 1, Characteristic part of the sub-claim characterized in that at a fixed distance from the measuring tube, a metal channel is arranged so that the surface opposite the measuring tube is metallic, however, the side facing away from the measuring tube is provided with insulation.