The thermopulse thermometer for measuring the temperature of liq u id d
comprises transmitter A and receiver D . Transmitter A consists of shell 3
in which a contacting device is mounted. This device is made up of fixed
contact b and movable contact a, secured on insulated b im e ta llic strip /
hav ing w ind ing 2. One end of w ind ing 6 is connected to w ind ing 2. W in d ing
6 is arranged on b im e ta llic strip 5, which is linked to hand 4, tu rn ing
about fixed axis E . Through ign itio n switch 7, the other end of
w ind ing 6 is connected to power source 8. When switch 7 and contacts a
and b are closed, current is set up in coil 2 of transmitter A and winding 6
of receiver D . At this, b im e ta llic strip /, heated by the current in its
w ind ing 2, bends upward, opening contacts a and b and breaking the
circuit so that there is no longer current in the transmitter coil and, consequently,
in the receiver coil. As it cools, b im e ta llic strip / straightens
out, closing contacts a and b. The heating and, consequently, deformation
of b im e ta llic strip 5 of receiver D correspond to the current pulses
transmitted by the closing and opening of contacts a and b in transm itter
A . The frequency of pulsation of contacts a and b and, therefore, the
length of the current pulses in w ind ing 6 depend on the heating of strip 1
by current in its winding, as well as on the temperature of the surrounding
m edium d . When this temperature is lower, b im e ta llic strip 1 cools
faster after opening contacts a and b. Owing to the consequently shorter
time d uring which contacts a and b are in the open state, the number of
current pulses increases. Therefore, the average current in w ind ing 6
of receiver D increases w ith a reduction in the temperature of surrounding
medium d. This increases the deformation of b im e ta llic strip 5 and the
deflection of hand 4 linked to the strip. The scale along which hand 4
moves is graduated in temperature units.
$4403$SmE,M$