US2113326A - Heat alarm system - Google Patents

Description

April 5, 1938. p. F. KRO@- HEAT ALARM SYSTEM Filed July 25, 1935 A Harney Patented Apr. 5, 1938 UNITED STATES PATENT OFFICE 1 Claim.

This inventionrrelates to a thermostatic or heat operated switch, the general object o the invention being to provide a heat operated switch of superior simplicity and ruggedness, which is 5 readily adjustable to operate at different temperatures.

Other important objects of my invention will be apparent from a reading of the following description in connection with the drawing, wherein for purposes of illustration I have shown a preferred embodiment of my invention.

In the drawing:-

Figure 1 is a transverse vertical sectional view taken through the thermostatic device.

Fig. 2 is a side elevational view of Figure 1 taken from the left thereof.

As shown in the drawing, the switch 22 comprises the tubular metallic part 24 which has a relatively reduced bore 26, the lower end leading into one side of the upper part of a cylindrical chamber 2l which is arranged with its axls horizontal. The chamber 2l is formed in a sectional block composed of the upper section 28 integral with the tube 24 and the lower separable section 29 which is assembled to the upper section by means of bolts 30 which traverse the side walls of the chamber as indicated in Figure 2. The tube 24` is conveniently arranged through an opening in a support 3l.

A binding post screw 32 traverses the side of the tube 24 below the enlarged bore portion 35 and is in contact with the mercury 33 which fills the interior of the chamber 21 and the tube 24. The binding post 32 is provided for convenient connection with the regular house current.

Inserted into the enlarged bore portion 2l is the vitreous insulating material tube 34 preferably of glass or the like and this is held in place by a cap 35 which is threaded on the exterior of the upper end of the tube 24 and contains a packing 36.

On the upper end of the insulating tube 34 is telescoped a dielectric block 3l in which is axially mounted a bushing 38 which is both exteriorly and interiorly threaded, exteriorly to receive the 45 binding post nuts 39 and interiorly to receive the electrode which is', by virtue of this arrangement vertically adjustable in the bushing 38. It is obvious that by adjusting the electrode 40,

(Cl. 20o-141) the height to which the mercury 33 must rise to make contact with the lower end of the electrode 40 is predetermined, and by this arrangement, the switch is adjustable to operate at a considerable range of temperatures. For convenience gauge markings 4I on the exterior oi the translucent dielectric tube 34 are placed at vertical intervals and designate degrees of temperature and at the same time the height to which the mercury will rise at a corresponding temperature to engage the lower end of the electrode 40. The mercury is clearly visible so that its height may be compared with the various gauge markings.

Although I have shown and described herein a preferred embodiment of my invention, it is to be denitely understood that I do not desire to limit the application oi the invention thereto, and any change or changes may be made in the materials, and in the structure and arrangement of the parts, within the spirit of the invention and the scope of the subjoined claim.

What is claimed is:

A mercury switch comprising a casing formed of upper and lower sections detachably connected together and forming a horizontally arranged cylindrical chamber, a vertically arranged tubular part connected with the upper section and having the lower end of its bore entering the chamber at one side and below the top thereof, the upper part of the bore of the tubular part being enlarged, a transparent tube having its lower end tting in the enlarged part of said bore, packing means for holding said end of the transparent tube in position, a block of non-conducting material fitting over the upper end of the transparent tube, a metal sleeve having its lower part `fitting in the block and contacting the upper end of the transparent tube, the sleeve being internally threaded, a rod having a threaded part passing through the sleeve, with its lower part located in the transparent tube, the upper part of the sleeve being exteriorly threaded, nuts on said threaded part, and a contact member carried by the tubular part of the casing and contacting the mercury in the reduced part of the bore of said 5

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