US1925530A - Thermostat - Google Patents

Description

Sept, 5, w33. F. GOTTHARDT THERMOSTAT FilKed April 2, 1931 ATTORNEY Patented Sept. 5, 1933 UNITED STATES PATENT OFFICE 16 Claims.

AThis invention relates to thermostatic control devices in general, and particularly to the kind employing expansible liquids as a temperatureI influenced element.

The prime objects of my invention are to provide a device of this kind which will -be sensitive and accurate and at the same time inexpensive and relatively small, compact and inobstructive, and extremely simple, both as to structure as Well as to its installation. c

Another object of my invention is to 'so design my device as to completely eliminate inaccuracies often found in similar instruments, due to formations of vacuum and theconsequent evap- '.esting its adjustability to subsequent volume changes beyond or below the desired temperature setting.

Still another object of my invention resides in providing such adjustable control means with a circular, calibrated scale, and to so construct said control means, that one nearly complete turn thereof will cover the entire range of temperature adjustments, readable from the scale, and

that by certain movement of said control means the latter will cause the actuation of any device, intended to be regulated by, or connected with my thermostat, without regard to any subsequent volume changes of the fluid induced by variations in temperatures.

A further object of my invention is to provide a thermostatic device for regulating heat supply control means, in which the major body of expansible liquid intended to be influenced by temperature changes is remote from such supply control means, while its adjustable temperature setting provisions are in close operative relation to said supply control means, and are .adapted to effect the regulation or closing of the latter by direct contact.

A still further object of my invention is to provide the aforedescribed form of my thermostatic device with more than onenon-mixable expansible fluid of lower and higher' coeilicient of expansion, and to employ the fluid of a lower CO- eflicient at parts directly affected by or in close proximity to the heat supplying element.

' The foregoing and still further objects of my invention will be more fully apparent from the following description and the accompanying drawing, forming part of my disclosure and embodying more or less diagrammatical illustrations of my devices for explanatory purposes only, but by no means intended to limit my invention to th actual showing, and in which- Fig. 1 illustrates my device invertical cross section, and is shown connected with a control valve, partially in cross section;

Fig. 2 is afront elevation of my device, illustrating my dial equipped regulating mechanism;

Figs. 3, 4, 5 and 6 are diagrammatical illustrations of my device and a heat supply control valve connected therewith in different stages of operation;

Fig. 7 illustrates a portion of a modified form of my device, and

Fig. 8 is a cross sectional view of another modification thereof as applied directly to a heat supply controlling valve.

Before describing my apparatus and its functions in detail, it may be well to state that devices of similar nature and for similar purposes have been employed, that, however, such devices employed displacement members, as for instance diaphragms, bellows, etc., which were inaccurate in their reactive functions induced by the volume changes of expansible liquids of such devices. Furthermore their movements were not confined to a purely one-directional function, as their construction permitted their expansion in more than one direction. Moreover, the adjustment of these devices was invariably based upon changes inthe volume of the vessel holding the liquid without seriously taking in consideration whether or not the liquid always completely fills the vessel, or whether or not a vacuum formation within the latter takes place when the volume of the vessel is increased. Such vacuum formation causes inaccuracies in the operation of the devices, which are entirely precluded in my apparatus.

Referring now to Figs. 1, 2, 3, 4', 5 and 6, numeral 10 denotes a closed chamber connected by means of tubing 11, to valve stem housing '12, all of whichl three members form a hermetically sealed, rigid, unyieldable vessel completely filled with one or more expansible lluids, the latter adapted to react to changes in temperature by either expanding or contracting, thereby changing its volume. Secured within and sealed at sealed and closed at 14 and extending from that free end is a rod or pin 15, provided with head 16 adapted to serve as stop for washer 17. Be'- tween end 14 and washer or ring 17 a spiral spring 18 is mounted, which is always under tension and normally causes washer 17 to bear against head 16. Spring 18, together with ring or washer 17, forms a resilient abutment which is compressible, but which lcannot expand beyond a certain limit set by head 16. In other words the spring 18 with washer 17 and the rod 15 with its head 16 form a buffer.

The attached end of displacement member 13 is secured to an enlargement 19 forming part of chamber l0, and shaped in the form of a bushing, having a circular ilange 20 serving as a dial provided with calibrations indicated in Fig. 2. The bushing is internally threaded for receiving an unyieldable, but adjustable abutment member 21 which is hollow, so as to accommodate head 16. Member 21 is equipped with handle 22 which serves also as indicator for calibratedscale 20. Abutment member 21 is designed to 'cooperate with and serves as stop means for the resilient abutment elements within displacement body 13, and both abutment units comprise the control or adjusting mechanism of my device, as will be presently evident.

Valve stem housing 12 comprises also an unyieldable, preferably cylindrical body, one end of which connects by means of unyieldable tube 11 with chamber 10, while the other end is hermetically sealed. Secured at this sealed end of the housing is the open, fixed end of a bellows member 23, much smaller in diameter than displacement body 13, but constructed also of seamless, spirally rolled and ridged material, which has the tendency of expanding or contracting in longitudinal direction only, while its lateral dimensionsvremain unchanged for any practical pulpOSeS.

The' internal or closed end of bellows member 23, indicated at 24 in Fig. l, is sealed, and secured thereto is the stem 25 of valve cone 26. The latter is adapted to control the passage 27 provided in Valve housing 28, through which gas, steam or hot water is supplied to a heating unit, as for instance a radiator. Through the movement of valve 26 the amount of a heating medium entering through passage 27 may be regulated.

Due to the fact that bellows member 23 is smaller in diameter, that its spiral ridges are finer or smaller, and that its length in proportion to its diameter is greater than that of the displacement member 13, the longitudinal movemenJ of bellows member 23 will be over a rela-v tively longer distance than that of displacement member 13. This results in an appropriate long motion of valve stem 25 providing an accurate control of the heating supply.

In the diagrammatic illustrations of my device seen in Figs. 3, 4, 5 and 6, the valve s tem housing is illustrated in the form of a cylinder and the valve stem is shown in the form of a piston 'movable therewithin.

Operation ,.Fig. 3 corresponds to Fig. 1 and illustrates my device in a state, at which the expansible liquid within the vessel is as yet unaffected by heat. Let us say that the liquid is contracted to a certain extent, and its volume therefore, reduced. In consequence of the volume reduction of the liquid, displacement member 13 is expanded and valve stem 25 is at its innermost position within valve stem housing 12. This position of the valve permits the heating medium to freely enter the radiator, which latter will transfer heat to the room in 'which is located chamber 10.

In the diagram shown in Figure 3 the position of the displacement body is intended to illustrate the extreme expansion'of the latter within the vessel, that is, when the volume of the liquid surrounding the body is reduced to its lowest point, due to the exposure thereof to the lowest possible temperature. vIt will be seen that the sealed end 14 of the body ,does not touch the bottom of compartment 10, although the body is atgits extreme expanded position.

At the moment rigid, adjustable abutment 21 of handle 22 is set to a higher temperature, the

yieldable abutment within displacement body 13 stands remote from abutment 21.

I refer now to Fig. 4. The moment heat reaches chamber 10 the liquid will lincrease in volume and exert a pressure against the walls of all parts of the vessel comprising my instrument. Due to its relatively greater diameter and elasticity, displacement member 13 will be rst affected by the increasing volume of the liquid and will be compressed until washer 17 of the resilient abutment member will come in contact with unyieldable abutment member 21. Spring 18 being relatively strong will prevent further compression of displacement body 13.

The liquid, however, continues to expand, and since it cannot compress body 13, it will divert through tube ll into cylinder 12, and will exert pressure (through bellows member 23) against valve stem 25 and move the latter gradually first to a throttling, and finally to a closing position of valve 26. The closing of the valve prevents heating media from entering the radiator, causing the latter to cool, thereby lowering the temperature of the room in which my device is placed (see Fig. 5).

Figures 4 and 5 illustrate the usual operation of my device at which the yieldable abutment member within displacement body 13 is in normal contact with rigid abutment 21.

The lower room temperature reduces the volume of the expansible liquid in the vessel, and causes bellows element 23 to gradually expand until valve 26 is again brought to its opening position, permitting the entry of heating media into the radiator. The foregoing process is thus re peated in maintaining the room at a desired, uniform temperature, to which my device is adjusted.

The adjustment of my thermostat 'is accomplished by turning indicator handle 22 to' the required setting. Assuming that the device is to be adjusted to maintain a lower room tempera; ture, the handle is turned in and towards spring 18. Thus when at such setting the liquid expands,

the movement of displacement body4 13 will be 'j dle 22 is moved outwards and from the resilient abutment of the displacement body 13. When it is desired to keep the valve permanently closed, a procedure similar to that of lowering the room temperature is followed. In this case, however, the unyieldable abutment is moved in completely against the resilient abutment, thereby bringing spring 18 under a tension higher than normal. Consequently, washer 1'7, instead of bear-ing against head 1.6, rests against the screwed-in end of abutment 2l. This setting causes the displacement body 13 to exert a greater than normal pressure against the liquid, resulting in the closing of the valve (see Fig. 6).

Referring to modification of Fig. 7, the only difference in construction resides in providing instead of pin 15 (Fig. 1), a cylindrical shell 29 equipped with a stop flange 30, against which normallybears disc 31, forced thereagainst by spring 18. Thus a yieldable abutment of a modified design is secured in displacement body 13'. Unyieldable abutment 21 in this modification. represents a solid, instead a hollow screw.

Fig. 8 represents another modification of my device, adapted for use in connection with a valve housing where the displacement body may be brought in direct contact with the valve stem, while the part of the vessel intended to contain an expansible liquid, consists of a separate chamber which may be located at any place of the room. In this figure numeral 32 indicates a valve housing into which is inserted a casing having a wide upper chamber 33 and a reduced lower valve stem chamber 34, in communication with the former. The upper chamber is equipped with a displacement member 35 of large diameter, while in chamber 34 a bellows member 36 of small diameter is located. Connected by means of tubing 3'7 to chamber 33 is a chamber 38 adapted to contain expansible liquid of a relatively high coeicient of expansion, while chambers 33 and 34 yare filled with a practically non-expansible fluid, or a fluid of much lower expansion coeiiicient, and which will not mix with the liquid in chamber 38. It is understood, of course, that the vessel, comprising all connected units, is completely filled by the fluids.

The use in chambers 33 and 34 of a iiuid having a low expansion coefficient eliminates inaccuracies due to exposure of these chambers to the direct influence of the heating medium passing through the valve housing.

The operation and adjustment of this modified device .is the same as that described above, however, its regulation is accomplished by a hollow knob 39 which, when screwed down tightly against the resilient abutment element within displacement body 35, will cause the free end of the latter to engage and bring to'a closing position valve 40, when desired. I preferably interpose between body 35 and bellows member 36 an expansion element, which however is not shown.

n vices it will become readily evident that although any sort of adjustment is made possible by the cooperative movements of the resilient and unyieldable abutment elements, the flexible displacement body will alwaysconform with and adjust itself to subsequent volume changes of ,the liquid, induced by variations in temperature.

It is obvious also that While the flexible abutment element is described in specific form, a simple spring under constant tension, and limited in its outward movement may be substituted.

Likewise the general arrangement and construc- T tion of the different parts of my device may be designed in other forms, as long as the basic principle of my invention is not altered, that is, that no matter what adjustment is made thevessel will always remain completely filled by the liquid, and that neither vacuum, nor elastic gases can form therewithin, due to the instant conformability and adjustability of the displacement body to volume variations.

An important feature of my device, evident from the drawing, resides in the arrangement of the resilient abutment relative to said displacement body, in that the hollow space within the body is usefully employed for accommodating and housing the resilient abutment structure, thereby effecting a saving in space and material and reducing the size of my device to a compact unit.

While I have shown and described specific forms of my invention, changes and improvements may become necessary due to its manifold applicability to different uses other than indicated, as -for instance in control devices for refrigerators, and I therefore reserve for myself the right to incorporate such modifications without departing from the broad scope of my idea.

I claimi 1. In a thermostatic control device, a closed vessel completely filled with relatively noncom.-

pressible, expansible media, heat supply control means and a displacement body associated with said vessel, said body adapted to conform and adjust itself to volume changes of said media induced by variations in temperature, control means for governing the operation ofv said body,

` thereby influencing the pressure within said vessel Without arresting the bodys ability to adapt itself to the volume changes of said media, said control means comprising a yieldable abutment element disposed within said body, and an adjustable but unyieldable abutment member associated with said vessel and adapted to be brought into engagement with said yieldable element, when desired, said yieldable element beingr permanently under a certain fixed tension and to a desired temperature, a valve for regulating the iiow of heating means and a displacement body resilient in one direction arranged within said vessel, said body being able to adapt itself to changes of volume of the expansible liquid, a rod arranged within said displacement body and firmly connected therewith, an abutment on said rod, an adapting piece movable on said. rod up to said abutment and a spring pressing said adapting piece against said abutment.

3. In a thermostatic control device, a control mechanism including a closed vessel filled with an expansible liquid .and adapted 'to be adjusted to a desired temperature, a valve for regulating the flow of heating means, a displacement body resilient in one direction only arranged within said vessel, said body being able to adapt itself to changes of the volume of the expansible liquid, a rod arranged within said displacement body and rml'y connected therewith, an abutment on said rod and a spring having its movable end pressing against said abutment.

4. In a thermostatic control device, a control mechanism including a closed vessel lled with an expansible liquid and adapted to be adjusted to a desired temperature, a valve for regulating the flow of heating means, a displacement body within and under the influence of said liquid arranged within the casingof said valve, said body being adapted to be brought in contact with said valve for closing the latter manually, when desired.

5. A thermostatic control device for governing the supply of a heating medium, comprising a relatively unyieldable vessel completely lled with one or more relatively noncompressible noninetallic, expansible liquids, a valve controlling the supply of a heating medium and a resilient displacement member within said liquids associated with said vessel and under the iniiuence of said liquids, a yieldable abutment disposed within said body and comprising resilient and rigid members, the latter holding the former under xed tension, an adjustable unyieldable abutment operatively lodged with said vessel and in cooperative position with said yieldable abutment.

6. In a thermostatic control device, as set forth in claim 5, said body and said valve arranged in cooperative relation to one another for facilitating the closing of the valve directly by said body irrespective of volume changes of said liquids.

7. A thermostatic control device for governing the supply of heating media, comprising a relatively unyieldable vessel, two expansible non-metallic, non-mixable liquids having a different coefficient of heat expansion completely filling said vessel, a valve for controlling the supply of heating media and a resilient displacement body associated with said vessel and surrounded by said liquids, the liquid having a lower coemcient of expansion in contact with all parts of said body exposed directly to the iniiuence of said heating media, a yieldable abutment disposed within said body, an adjustable unyieldable abutment in cooperative relation with said yieldable abutment operatively lodged with said vessel, said body being disposed in operative relation to said Valve for facilitating the closing of the latter through the movement of said body, induced by the manual operation of the unyieldable abutment against said yieldable abutment, the latter comprising a resilient and a rigid member, said resilient member held under fixed tension by said rigid member.

8. In a thermostatic control device, a control mechanism including a closed vessel, a displacement body within said vessel, a valve for regulating the ilow of heating means connected With said vessel, said control mechanism comprising a rigid, adjustable abutment operatively secured with said vessel and an yieldable abutment, normally under a deiined tension, disposed within said displacement body, said abutments in cooperative relation with one another, expansible, non-mixable liquids of a high and low coefcient of heat expansion Within said vessel, the liquid of lower coeiicient of expansion in contact with all parts directly exposed to the influence of said heating means.

9.The combination with a thermostatic control device, including a displacement body, of an abutment element within said body composed of yieldable and rigid members, said yieldable member held permanently under a dened normal tension by said rigid member, both members 4adapted to move bodily with said displacement body, -said yieldable member being capable of dimensional changes due to an increase in its tension beyond itsF normal tension.

10. The combination with a thermostatic control devicehaving a movable displacement body, of an abutment associated with and disposed within the latter and composed of a compressible spring member and a rigid member holding said spring member constantly under a certain normal tension, both members" adapted to simultaneously move, in theirnormal relation to one another, with said body, said spring member capable of being compressed beyond its normal tension at which it is held by said rigid member.

ll. The combination with a thermostatic control device, including a displacement body, of an abutment element within said body composed of yieldabler and rigid members, said yieldable member held permanently under a dened normal tension by said rigid member, said yieldable member being capable of dimensional changes due to an increase in its tension beyond its normal tension.

12. In a device as'described, a closed liquid iilled relatively-unyieldable vessel and a resilient valve operating body connected with said Vessel and influenced by said liquid and a resilient displacement body within said vessel and a builer within said displacement body composed of a spring and a rigid abutment adapted to limit the movement of said spring and able to make or break engagement with said spring and a separate second abutment attached to said vessel and able to make or break engagement with said spring.

13. In a device as described, a closed liquid filled relatively unyieldable vessel and a resilient valve operating body connected with said vessel and iniiuenced by said liquid and a resilient displacement body within said vessel and adapted to always conform and adjust itself to excessive expansion and excessive contraction of said liquid, and a buier within said displacement body composed of a spring and a rigid abutment adapted to limit the movement of said spring and able to make or break engagement with said spring and a separate second abutment attached to said vessel and able to 'make or break engagement with said spring.

14. In a device as described, a closed liquid lled relatively unyieldable vessel and a resilient valve operating body connected with said vessel and influenced by said liquid and a resilient displacement body within said vessel adapted to always conform and adjust itself to excessive expansion and excessive contraction of said liquid, and a buffer within said displacement body composed ofA a spring and a rigid abutment adapted to limit the movement of said spring and able to make or break engagement with said spring and a separate second abutment for setting the device for a desired temperature attached to said vessel and able to make or break engagement with said spring.

15. In a device as described, a closed liquid lil and able to make or break engagement with said spring and a separate second abutment attached to said vessel and able to make or break engagement with said spring, both the abutments being able to come into alternating engagement with said spring on movements of the displacement body.

16. In a ldevice as described, a closed liquid lled relatively unyieldable vessel and a resilient valve operating body connected with said vessel and influenced by said liquid and a resilient displacement body within said vessel adapted to always conform and adjust itself to excessive expansion and excessive contraction of said liquid, and a buifer within said displacement body compoed of a spring and a rigid abutment adaptedtdf'limit the movement of said spring and able to `make or break engagement with said spring and Iav separate second abutment attached to said vessel and able to make or break engagement with said spring, such rigid abutments being fastened to said displacement body and moving with said displacement body and the spring.

FRITZ GOTTHARDT.

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