US2179838A

US2179838A - Temperature control device

Info

Publication number: US2179838A
Application number: US204918A
Authority: US
Inventors: Lloyd L Young
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1938-04-28
Filing date: 1938-04-28
Publication date: 1939-11-14
Anticipated expiration: 1956-11-14

Description

Nov. 14, 1939. L. L. YOUNG TEMPERATURE CONTROL DEVICE Filed April 28, 19:58

INVENTOR. LLOYD L. YOU/VG ATTORNEY.

Patented Nov. 14, 1939 PATENT V OF'FlCE TUBE OONTBOL DEVICE Lloyd L. Young, Patchogne, N. Y., assignor Radio Corporation of America, a corporation ofDelawarc Application April as, 1938, Serial No. 204,912; .12 Claims. (01. 219-38) This invention relates to a new and novel method of temperature control and deals specifically with a device for the control of self-contained heat generation and/or control of electric current for any purpose.

An object of this invention is to simplify and- A further object of this invention is to provide I ll smooth temperature regulation to such devices as a piezo-electric crystal employed for accurate control of frequency in a radio circuit.

The features of this invention are based upon the principle of Archimedes as illustrated by the well known Cartesian devil" and also upon the principle of Faraday's law of electro-magnetic induction. I

This invention is particularly directed to two forms, one form in which the heat is generated by Foucault currents, or eddy currents, the other form being arranged such that heat is generated by electric currents flowing through high' resista'nce conductors.

In the prior art practice, the current generating heat in high resistance conductors was gen- I erally controlled by means of contact electrodes with or without complicated vacuum tube circuits and also employed mechanicai'electro-magnetic relays or mercury circuit breakers. By my invention, all such circuit breakers and contact electrodes are eliminated. Furthermore, the use of all thermostats or like devices is dispensed with, thus materially reducing the cost of the temperature control system. A feature of this invention is that it provides a smooth continuous regulation instead of in steps, as many of the prior art devices.

Another feature of this invention is that it may be used as a pressure regulator.

This invention may best be understood by referring to the accompanyi g drawing, in which:

l lg.lisanctiopthm ahasimpleformof tcmperaturecontrcldflm;

mJaisaplanvilwofl lgi; 5o m.2isanothermcdlflation gsgornblyoi Fig.1; and

. plgflisanotherunbodlmantinwhichthedw viceis'surroundedbytwowindings. neferringnowindetailtomlandlman insulatingcontainerlisprovidedwitharemovofthe floating able cover 2, the under portion of which may be provided to retain a suitable oven or container 3, within which may be located a piezo-electric crystal holder (not shown) or any other device in which the temperature is desired to be maintained substantially constant, suitable electric connections being made to the device whose temperature is to be controlled by means of leads I and 5.

Within casing l is located a fluid 6 such as, for example, alight grade of oil or any other suitable material. Surrounding the lower portion of insulating casing l is a coil winding 1 which is arranged for setting up astrong magnetic field by being connected to a suitable source of alternating current voltage 8. Located approximately withinthe central portion of the casing, a Cartesian devil 9 is secured by means of fine threads I, which prevent the floating assembly from touching the sides of the container, but permit ample freedom of vertical movement. Within element 9 there is maintained an air pocket I l which responds to changes in temperature and pressure by volume changes. Member 9 is weighted down by a plurality of weights I! which are in the form of continuous metallic ring-like conductors, the number and size being maintained such'that the displaced oil nearly balances the weight of. member 9. An opening l3, which is closed by means of a threaded stud l4, permits inspection of the oil level and its replenishment when necessary.

In the operation of i is cold,the air in the buoyancy of element I0 is decreased so that the floating element 9, with the associated rings I2, sinks and the flve threads Ill suspend the floating element 8 inside of the coil I. When power is applied to coil I, a strong field of magnetic ilux is set up around the shorted turns l2, causing large currents to flow which, because of the resistance in the shorted turns 12, gener ates heat, thus heating the oil 8. When the oil becomes sufllciently heated and the air within chamber II is warmed, the air expands, perthis device, when the liquid mitting the float 9 to rise gradually, leaving the zone of the strong magnetic field. As the float causes the turns I! to recede from the magnetic fleld, the currents in rings I! become smaller and by the process of slow hunting," the float S will come at rest to a point where the fleld strength is just enough to induce currents in shorted conductor l2, which generates suflicient heat as is dissipated, so that the temperature of theoilisthenmaintainedconstanti space H is contracted and a with reference to Fig. I, except that the heat is generated in the metal shell I5, by eddy currents set up in the shell by the alternating magnetic fleld from the winding I, which in this case is energized by alternating currents of suitable frequency.

Referring now to Fig. 3, part of the heat is produced by means of eddy currents occurring in a shell l6 which is'preterably composed of magnetic material acting as a booster heater, andpart by the heater resistance member H which is enersized by a secondary winding I 8 which forms part ora transformer, having an external core or cup 19 and cover 2|, which aids in theoperation oi the device. The operation of Fig. 3 is such that when the float 9 is in the lower. position, the shell I6 is in such a position that the strong magnetic flux i'rom coil I threads or cuts the turns of coil it, strongly inducing a current to flow. causing a decrease in 'the reluctance of the magnetic circuit. As floating element O'rlseathe magnetic material of i6 is withdrawn from the fleld and the flux is not so strong through and around coil .II, so that the heating current in i1 is decreased. The float 8 will then seek a position of rest as in the cases, of the devices described in Figs. 1 and 2, wherein the heat generated just equals the heat dissipated and the temperature of the device becomes substantially constant. The application of these devices may vary. as, for instance, if the current in coil ll of 1"18. 3 is passed through a meter (not shown) it may be calibrated to read in terms of temperature. Various devices requiring close and smooth temperature control may utilize the devicesoi this inven-: tion. Also, another application of a device similar to that of Fig. 3 is that there is-connected in i the circuit of soil It a relay, polarized so that a pressure pump may be controlled .as, for example, in'a refrigerator. 4

There are various other modifications that could be made in the above devices. such as causing movement of the float II to make and break the electrical circuits; also, to change the reluctance in a magnetic circuit. Therefore, this invention should not be limited;to the .precise devices shown.

What is claimed is:

, 1. A temperature control device comprising an insulating casing, a coil surrounding said casing, a liquid whose temperature is maintained constant within said casing, a floating element in said liquid, a ringlike medium member. secured .tosaid floating element, and means for passing an alternating current. through said coil whereby eddy currents set up by said ring-like member heat said liquid to a desired constant temperature.

.2. A temperature control device comprising an insulating casing, a coil surrounding said casing, an oil-like liquid within said casing, a floating element in said liquid, a ring-like metallic' meniber secured to said floating element, and means for passing an alternating currentthrough said coil whereby eddy currents set up by said ringlike member heat said liquid to a desired constant temperature.

3. A temperature control device comprising an insulating casing, a coil surrounding said casin a liquid whose temperature is maintained constant within said'casing, a floating element having a space filled with air the volume of which changes with the temperature of said liquid, a

' ring-like metallic member secured to said floating element, and means for passing an alternatingcurrent through said coil whereby eddy currents set up by said ring-like member heat said liquid to a desired constant temperature.

4. A temperature control device comprising an insulating casing, a coil surrounding said casing, a liquid whose temperature is maintained constant within said casing,a floating element in said liquid, a metal shell member secured to said floating element, and means for passing, an alternating current through saidicoil whereby eddy currents set up by said metal shell me'mber heat said liquid to a desired constant temperature. 5. A temperature control device comprising an insulating casing, a coil surrounding saidcasing, a liquid. whose temperature is maintained-constant within said casing, a floating element in said liquid, a metal shell of magnetic material secured to said floating element, and means ior passing 6. A temperature control device comprising aninsulating casing, a coil surrounding said casing,

a liquid'whose temperature is maintained constant within said casing, a floating element in said liquid, a long narrow metallic shell of magneticmaterial secured to said floating element, and means for passing an alternating current through said coil whereby eddy currents set up by .said metallic shell heat said liquid to desired constant temperature.

floating element in said liquid, a ringlike metallic member secured to said floating element, and means for passing. an alternating current through at least oneoi-said coils whereby eddy currents set up by said ring-like metallic member heat said liquid to a desired constant temperature. 1

.7. A, temperature control device comprising.-

8. A temperature control device comprising an insulating casing, a plurality of coils surrounding said casing, a heating coil located within said casing and connected to a=source' 01 power, a a

liquidwithin said casing, a floating element in I said liquid, a ring-like metallic membersecure'd to. said floating element, means for passing alternating current through at elast one of said coils whereby eddy currents are set up by said metallic member causing heat liquid at a desired temperature. I 9. A temperature control device comprising an insulating casing,- a coil surrounding said casing,

a liquidwhose temperature is maintained c0n-" stant within said casing, a piezo-electric crystal which maintainssaid element surrounded by said liquid, a floating element in said liquid, a ring-like metallic member secured to said floating element, and means for passing an alternating current to said coil whereby eddy currents set up by said ring-like member heat said liquid to a desired constant temperature.

10. A temperature control-device comprising an insulating casing having a cover, a piezo-electric crystal secured to said cover, a liquid whose temperature is to be maintained constant within said casing, a floating element in said liquid, a ringlike metallic member secured to said floating element, and means for passing an alternating current through said coll whereby eddy currents set up by said ring-like member heat said liquid to a desired constant temperature.

11. A temperature control device comprising an insulating casing, a transformer having a core and a plurality of coils surrounding said casing, a heating coil located within said casing and connected to one of the coils of said transformer, a liquid within said casing, a floating element in said liquid, 2. ring-like metallic member secured to said floating element, means for passing an alternating current through at least one of said coils whereby eddy currents are set up by said metallic member causing heat which maintains said liquid at a desired temperature.

12. A temperature controlling device comprising a container filled with liquid, a body having a gas filled space floating in said liquid, a member adapted to have heating currents induced therein carried by said body, and means relatively fixed in position with respect to said container inducing currents in said member whereby the induced currents flowing in said member cause heating of said liquid thereby changing the volume of gas in said body and thereby causing said body to float to a position such that the heat generated by said member substantially equals the heat dissipated by the liquid.

LLOYD L. YOUNG.