US939957A - Thermostat. - Google Patents

Description

H. G. GEISSINGER.

THERMOSTAT.

ArrLicnIon run nov. so, laos.

Patented Nov. 9, i909.

STATES rATENT orricn.

uHARRY e. GEIssINGER, or WEsT oRANGE, NEWJERsEmAssIGNoR To GErssINGRR REGULATOR COMPANY, A CORPORATION or NEW YORK.

THERMOSTAT.`

Specification of Letters Patent.

Patented Nov. 9, 1909.

Application'led November 30, 1908. Serial No. 465,336.

To all whom it may concern:

Be it known that I, HARRY Gr. GEISSINGER, a citizen of the United States, residing at West Orange, in the ycounty of Essex and State of New Jersey, have invented certain new and useful Improvements in Thermostats, of whichthe following is a specification.

My invention ielates to that class of aparatus by which electric circuits are reguated and controlled by changes in temperature, and its especial object is to provide a controlling devlce which shall be exceedingly sensitive to changes in temperature but entirely unaffected by disturbances due to vibrations or mechanical shocks, such, for instance, as are found upon moving trains or ships as well as the tremors due to the operation of machinery in buildings.

A further object of my invention is to overcome the uncertainty of the electrical contacts in such instruments occasioned by the presence of particles of dust or other insulating particles.

Some of the difficulties heretofore encountered in the use of thermostats of the compound-bar type has been due to the vibration or chatterin of the electric contacts, causing interruptions in the velectric circuit under control and a rapid destruction of the contact surfaces. Moreover, in the usual form of thermostat, the contact points are carried upon the free end of a bar supported from the other end and the initial contact takes place very gradually and with an extremely light pressure, and therefore makes a very uncertain contact. Any dust or foreign particles clinging to the contact surfaces will resist the light initial pressure and thus cause a delay in the closing of the electric circuit, whereby the temperature con-f trol is rendered uncertain and inaccurate.

My improved thermostat overcomes the difficulties above enumerated and provides an apparatus which is free from the influence .of mechanical disturbances due to vibrations and shocks, and responds quickly to temperature changes, producing a ositive and firm initial pressure of the sur aces of the electric contact members. In my former patent, No. 887,087, I disclosed the principles of the free arch of a constrained flexible member and described one form of appratus in which this might be utilized.

y .present invention also employs a constrained flexible member freely arched between knife-edge bearings, and further provides an improvement in the method of making changes in the initial adjustment of the arched member and adjustments for control at different temperatures, and for controlling the contacts in two circuits corresponding to a maximum and minimum range of temperature. render that portion of the apparatus which is included in the electric circuits absolutely insensitive or neutral to temperature variations, and to control the electric 'contacts mechanically by means of an exterior thermal couple, or to place the contacts under the combined control of said exterior couple and of the members carrying the contacts.

My invention will be more fully understood by reference to the accompanying drawings in connection with the following description, while its scope will be pointed out in the appended claims.

Referring to the drawings, Figures 1 and 2 are plan and side elevations respectively of one form of my thermostat; Fig. 3 is an illustrative diagram showing the manner of effecting a regulation for changes in temperature control; Fig. 4 is a plan view, partly in section, showing my thermostat embodied in the tank type, or of the balancing type providing for a control of the electric contacts exterior to the element carryin thecontacts; and Figs. 5 and G are detail sectional views of the latter type.

Inasmuch as'tlic main elements of the devices shown in Figs. 1 and 2 are also shown in the type illustrated in Fig. 4I have employed the same numerals in the latter fig- `ureto designate the corresponding parts.

, Referring to Fig. l, the parts are carried by a base plate 1, which is insulated from its support and is provided with a fixed block or lug 4, to which is secured one end of each of the two flexible strips or members 2, the opposite ends of which are connected by the block 5 which rests upon the raised portion 14 of the base plate. The flexible of the thermal couple, the other expansible 3, of some resilient material, which is bowed Furthermore, I am enabled to` strips 2 form' one of the expansible elements element of which is formed by the member I block 6 being respondin thereof. lin the expansible members 2 are the same as or'arched between the anchor blocks 6 and 7 seated in recesses in the blocks 4 and 5, the rigidly secured r 1ile the block 7 is pivotal mounted upon a pivot pin 9. It is prefera le that the ends of the member 3 be knife-edged and seated in V-shaped notches, the ends projecting well within the recesses in the blocks for the purpose of securing them against lateral movement.

The member 3 isgiven an initial or normal arch or bow, by means of the adjusting screw 10, when the parts are assembled, such that it will occupy an intermediate positionbetween contact screws 11 and 12 carried by lugs projecting from the base plate. As the members -2 expand and contract under changes of temperature, the connectingblock 5 slides over the surface 14, being maintained in enga ement therewith by the spring plate 15, ang causing changes in the pressure upon the sprin strip 3, with corincrease or ecrease of the arch nasmuch as th changes in length the changes in the chord subtending the arc of the member 3, each length of chord correspondin to a different radius of the arc, it is evi ent that tliemovement of the central oint or crown of the arched member will) be much greater than the corres onding movement of its end, the change in eng'th of the member 2 being-thus magnitied in the distortion of the arched member. Moreover, the pressure of the crown of the constrained arched member upon-the contact point 1l is a fixed pressure throughout the range of movement of the instrument, the amount of said pressure being regulated by the adjustment of the arch, be-l ing dependent upon the height of the crown or the versed side of the arc.

In order that adjustments may be made in the temperature control or the limiting temeratures at which the electric contacts shall Ee established, I have provided a means of changing the position of the arched member with respect.to the contact screws 11 and 12. In Fig. 3, I have shown in full lines the normal position of the parts of thermal couple, and in dotted lines the manner of changing the position of the parts by a lateral movement ofthe connecting end block 5. To

etl'ectthis adjustment, the end block 5 is provided with avlug 16, carrying a screw 17 aladapted to slide longitudinally along the ace of the short arm of the bell-crank lever 8, pivoted at .19, the longer arm of lever 18 bearing against the temperature adjustment screw 20. The latter is prevented from accidental movement and from vibration b the brake-nut 24 carrying the spring 25, which bears against the stop pm or screw 26. To insure a constant engagement of the guiding screw 17 against the lever 18,

,through through the lever 18 and screw 17, and thatl this lateral movement will change the relative position of the arched member 3, and thereby the temperature at which contact will be made wlth the contact screws 11 or 12.

The circuits containing the automatic switches or valves to be controlled are connected to the insulated contact screws 11 and 12, the common return circuit being made the arched member 3, base plate 1, and bmd'n post 13.

In Fig. I have illustrated a modification, which I have referred to as the tank type, and in which the operation of the contact member 3 may be under the sole control of an exterior thermal couple which may project into a tank or other vessel or compartment to be ture control. In this form of my invention I have shown the base plate expanded at one end into a disk-like head which is secured to but insulated from a flange 29, the latter being usually screwed or otherwise secured to a plate or bulk-head 30, which may ment. The inner tube is rigidly secured to the outer tube 31, by having inwardly directed flanges clamped between a conical wedge 33 and an end cap 32 drawn tightly together by the screw 38. It is important that the inner and outer tubes shall be in intimate contact so thatchanges in temperature in the outerI tube may be quickly conducted to the inner tube, while at the same time permitting a relative movement Without undue friction, and insuring absolute freedom from any vibration of said inner tube. This may be accomplished by sawing transverse slots 35 near each end vand splitting the intermediate portion longitudinally, allowing it to expand in the manner indicated in Fig. 6. The interchange of heat between the outer and inner tubes may be facilitated by filling the tubes with a heavy oil. The free end of the inner tube is secured to a movable plug 37 by means of a conical wedge 36 and screw 39.

To enable the relative movement of the tubes 31 and 34 to affect the arching of the member 3, I pivotally mount the anchorblock 6 upon a pin 8 and mount a in 40, insulated at 41, in the plug 37, t e pin It will be apparent that by placed under temperapassing through apertures in the head of the base 1 and lug-piece 4, and seating in a recess in the anchor-block G, in the manner shown in Fig. 5. To supplement the pressure of the member 3 in forcing the block 6 into contact with the pin 40, and also to prevent any vibration of block G upon its pivot 8, I mount a spring 2T upon 'the block contact point 12 to close another electric circuit. From this it will be evident that the control of the arched member 3 and the electrical circuits which include the respective contacts 11 and 12, may be under the mechanical control of the external thermal couple comprising the tubular members 31 and 34, and that said external couple may be inclosed in a; chamber entirely shut off from that portion of the apparatus connected to the electrical circuits. In this method of control it will be understood that if the members 2 and 3 are made of the same material or of materials having the same temperature coeflicient or thermic constant, and are properly proportioned,` the relation of these parts With respect to the contacts 11 and 12 are unaffected by the changes in the temperature, it being always desirable that the temperature within the tank or compartment be unaffected by changes in the external temperature. However, under certain circumstances it is advisable that the internal temperature of the compartment or chamber containing the tubular thermal couple, shall be dependent upon or bear a certain relation to the changes in the temperature external to said chamber. Under these circumstances the members 2 and 3 may be made of different materials and constitute a thermal couple which shall coperate with the elements 31, 34, in the control of the arched member 3, and the electric circuits affected thereby. This compound instrument when thus arranged to place the electric contacts under the control of the tivo thermal couples, I have termed a balancing-thermostat. since the temperature surrounding one partof the compound thermostat will be regulated to rise asv the temperature surrounding the other part falls, or vice versa. Thus, if 31 is the major expanding element of the eX- ternal thermal couple, a rise in the surrounding temperature causes the contact between the member 3 and contact point 11 to open, thus creating the balance above referred to. For example the tubular couple might project into a hot Water pipe or tank which it was desired to have increase in temperature as the temperature fell in the room in which the couple 2, 3, was located. (ln the other hand, if it is desired that the temperatures surrounding the two parts of the instrument shall be kept equal or rise and fall together, the major expanding members in the two parts of the instrument would be reversed in relative position. In either case the proportion of rise and fall is determined by the relative lengths of the parts of the thermostat, taking into consideration the different coefiicients of expansion of the component materials.

Various changes may be made in the proportioning of parts or inthe relative arrangement of the major and minor elements of the thermal couple within the scope of my invention and Without departing from the spirit thereof.

I claim 1. A thermostat comprisinga normally straight flexible member constrained into a free arch, two other flexible members, one upon either side thereof and having a different rate of thermic expansion therefrom, and connecting-devices connecting the ends of said members.

2. A. thermostat comprising a pair of flexible members substantially similar in construction and in thermic properties, rigid pieces connecting the opposite ends of said members, and an intermediate member constrained into a free arch between said pieces and subjected to the varying expansion and contraction of said members.

3. A thermostat comprising a plurality of fiexible members having different thermic constants, means connecting the endsfof said members, and means for changing the relat1ve positions of one member with respect to the other members.

4. A thermostat comprising flexilile'l'nembers having different thermic const-ants. means connecting the ends of said members,

' means for altering the relation of one mem- -ber with respect to the others. and separate means for altering the position of two members with respect to the third member. 1

5. A thermostat comprisingT a pluralityy of flexible members having different thermic constants, means connecting the ends of said members, and means for laterally adjusting the connecting means at one end of said fiexible members.

6. A thermostat comprising a plurality of flexible members having different thermic constants, means connecting the ends of said members, means for laterally adiusting one end of said flexible members, and means for effecting an independent longitudinal adjustment of one end of one of said members.

7. A thermostat comprising flexible elements having different thermic constants, one of said elements comprising two sepa rate flexible members, connecting blocks connecting the members at their opposite ends and the other element being normally straight and constrained into an arch by having its ends abutting said connecting blocks.

8. In a thermostat, a thermal couple comprising members having different rates of thermic expansion and contraction, means for connecting the ends of said members, one of said members being constrained at its ends and formed into a free arch, anchor blocks having bearing seats for the ends of said arched member, one of said blocks being pivotally mounted, and means for adjusting the same upon its pivot to thereby alter the arc of the arched member.

9. In a thermostat, a thermal couple comprising flexible members having different rates of thermic expansion and contraction, one of said members being constrained at its ends and forced into a free arch, end pieces rigidly secured to one of said members, anchor blocks seated Within recesses in said end pieces and having bearing seats for the ends of said arched member, one of said blocks being pivotally mounted, and means for adjusting the same upon its pivot to thereby alter the arc of the arched member.

10. In a thermostat,` a thermal couple com` prising members having diferent rates of thermlc expanslon and contraction, one of said members being constrained at its ends and forced into a free arch, connecting blocks connecting the members at their o posite ends, anchor blocks secured to said connecting blocks and having bearing seats for the ends of said arched'member, a link ivotally secured to one of the connecting lilocks, a spring engaging said link and maintaining a constant lateral pressure thereon, and a guide block adapted to receive said lateral pressure and serving to guide the longitudinal movement of the thermal couple during expansion and vcontraction.

11. In a thermostat, a thermal couple comprising` members having diil'ercnt rates of thermic expansion and contraction, one of said members being constrained at its ends and forced into a free arch, connecting blocks connecting the members at their opposite ends, anchor blocks secured to said connecting blocks and having bearing seats for the ends of said arched member, a link pivotally secured to one of the connecting blocks, a spring engaging said link and maintaining a constant lateral pressure thereon, a pivotally mounted guido block adapted to receive said lateral pressure and serving t guide the longitudinal movement of the thermal couple during expansion and contract-ion, and means for adjusting the guide block upon its pivot.

12. A thermostatic instrument comprising a pair of' flexible members,connecting blocks secured to the opposite ends of said inembers, a flexible member constrained into a free arch between said connecting blocks, and means for affecting the pressure upon said arched member dependent upon changes in temperature.

13. A thermostatic instrument comprising a pair of flexible members,connecting blocks secured to the opposite ends of said members, a flexible member constrained into a free arch between said connecting blocks, and means for varying the curvature of said arch dependent upon the changes in temperature to which the instrument is subjected.

14. A thermostatic instrument comprising a pair of liexible members,connecting blocks secured to the opposite ends of said members, a flexible member constrained into a free arch between said connecting blocks, and means for varying the curvature of said arch in accordance With changes in temperature to which a portion only of the instrument is subjected.

15. A t-hermostatic instrument comprising a pair of flexible members,connecting blocks secured to the opposite ends of said members, a flexible member constrained into a free arch between said connecting blocks, and means for varying the curvature of said arch in accordance with changes in temperature to Which a portion only of the instrument is subjected and independently of the temperature to which another portion of the instrument is simultaneously subjected.

16. A thermostatic instrument comprising a pair of flexible members,connecting blocks secured to the opposite ends of said members, a flexible member constrained into an arch between said connecting blocks, and

D struction and in thermic properties, rigid pieces connecting the opposite ends of said members, an intermediate member constrained into a f-ree arch between said pieces and subjected to the varying expansion and contraction of said members, an auxiliary thermal couple comprising members havin different rates of thermic expansion and contraction, and means connecting one of said members With one end of said arched member.

18. A thermostatic instrument comprising a thermal couple having a pair of iexible thermic expansion and contraction, and 10 members, one of said members being conmeans connect-ing one of said last named strained at its ends into a free arch, conmembers with one of said anchor blocks. necting blocks connecting the members at In testimony whereof I aTiX my signature their opposite ends, anchor blocks pivotally in presence of two Witnesses.

secured to said connecting blocks and hav- HARRY G. .GEISSINGER ing bearing seats for the ends of said arched Witnesses: member, an auxiliary thermal couple, com- EUGENE C. BROWN,

prising members having diierent rates of i E. P. CORBETT.

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