DE657747C - Device for indicating flammable gases - Google Patents

Description

Device for indicating combustible gases The invention relates to a Device for the display of gauzes, in which in a Meßlcatnmer in Lä :: gsricittt: ng stretched out an electrically heated thread - is what is to be examined Gas sweeps along. In the previously known devices of this type, the suffers Measurement under flow conditions of the gas around becomes imprecise. I? S can develop such pull-through accelerations. that in the devices flames and melting temperature: approx. which destroy the measuring thread and also cause ignitions lead to the outside; it is therefore possible to use these devices by everyone Measure concentrations of flammable gases.

According to Errindut, these deficiencies are eliminated by the fact that!% As Power supply lines for the lIel ', thread at the opposite ends of the measuring chamber .two cone-shaped bodies, pointing inwards, made of heat-conducting material -Material are provided, 'whose outer ends with the' metallic wall parts the chamber are in a thermally conductive connection and have such a diameter, They almost fill the chamber at their ends, as do the ventilation openings above and below in labor the ke-e'-shaped body lie, while the thread is in one Glass cylinder is arranged, which forms the central part of the measuring chamber, in such a way that the air flow in the longitudinal clearing of the thread is fed to this and a transverse passage through the tube or against the thread, which would disrupt the constant air flow, is avoided.

The cone-shaped bodies and the vents are adjustable, such that by moving the conical body the volume of the measuring chamber increases or decreases the airflow rate by adjusting the ventilation openings can be regulated, whereby the measuring comb: it can be tuned so that at Breath of explosive gas-air mixtures, the otherwise constant air flow automatically is interrupted at intervals, so that a heating period on each leg is a cooling period follows and the heating of the device is kept within moderate limits.

These interruptions in the constant air flow show up in the Thread as extinguishing or lighting up the same and can at the same time as striking Characteristics of the composition of the gas mixture are used. The built-in conical Due to their heat dissipation, bodies prevent any aureole and flame image in of the device and thus prevent the thread from being destroyed Outward ignitions prevented. On the drawing is the new one Device shown.

Fig. I shows a view of the device. Fig. A is a schematic Longitudinal section. On the middle part a of the measuring chamber, which consists of glass or the like, the two metallic heads b are attached. These heads b have ventilation openings c, which sand gridded with close-meshed wire mesh. In the heads b are cone-shaped Body built in, which at the same time serves as power supplies for the spiral twisted thread / serve, which extends through the middle piece a.

Since the middle piece.a acts as an insulator, the electrical current only over the thread / flow, which is appropriately made of a platinum alloy is made.

The device is for the purpose of commissioning between two resilient Current poles of a current source that is as constant as possible are plugged in and the thread / on a certain temperature heated by the electric current. This forms in the device exerts a certain airflow, the fluctuations of which depend on the changes in temperature of the thread, which are caused by the fluctuations in the gas concentrations will.

The measurement is carried out in a known manner by determining the electrical, Resistance of the measuring thread, the brightness fluctuations of the thread can also be followed directly.

Claims (1)

PATENT CLAIM: Device for displaying flammable gases in which An electrically heated thread is stretched out in a measuring tube in the longitudinal direction of the same is along which the gas to be examined strokes, characterized in that, that as power supplies for the thread at the opposite ends of the chamber two .with the tip inwardly directed cone-shaped bodies made of good heat-conducting Material are provided, the outer ends of which with the metallic Wandungst.eilern the chamber are in thermally conductive connection and one. have such a diameter that they almost fill the chamber at their ends, and also the ventilation openings above and below at the level of the conical body, while the thread is in one Glass cylinder is arranged, which forms the central part of the measuring chamber, in such a way that the air flow is fed in the longitudinal direction of the thread and a transverse passage through the tube or against the fadcil.