US2065703A - Temperature responsive device - Google Patents

Description

08 29,1936. H, HUBBARD 2,065,703

TEMPERATURE RESPONSIVE DEVICE Filed June 15, 1935 INVENTOR KQHLHHUBBARD BY 9 gmwn/ ATTORN Y Patented Dec. 29, 1936 UNITED STATES TEMPERATURE RESPONSIVE osvrca Karl E. Hubbard, Rochester, N. Y., assignor to Taylor Instrument Companies, Rochester, N. Y., a corporation of New York Application June 13, 1935, Serial No. 20,442 2 Claims. (01. 73-32) This-invention relates to temperature responsive devices.

Prior temperature responsive devices such as thermometers for use at temperatures as high as 1800 have been fragile, have been ill-adapted for recording at a plurality of remotely located stations and have not been arranged for checking at room temperatures.

' The main feature of the present invention is the provision of a high temperature thermometer which is rugged in construction, which is designed for multiple recording, which is selfchecking, which is relatively inexpensive to make and which is accurate.

Other features of the invention will appear from the detailed description and claims when taken with the drawing in which Fig. 1 illustrates a multiple recording thermometer of which the temperature responsive stem is shown in longi- 2 tudinal section and one of the recorders is shown in elevation with a portion of its front broken away to disclose the operating mechanism thereof and two other recorders are indicated by fragments of their cases; Fig. 2 is a vertical section taken on the lines 2-2 of Fig. 1; and Fig. 3 is a horizontal section taken on the line 33 of Fig. 1.

Referring especially to Fig. 1, 5 designates a furnace wall through an opening 8 in whichthere extends into the interior of the furnace the expanding stem section I of the thermometer oi' the present invention. This stem section, which is supported by a head 8 mounted on the outside of .the wall of the furnace, includes a relatively short central rod 9 made of high expanding alloy-with a relatively inert transmission rod 10 and an outer tube ll having one closed end and one open end. The rod 9 may be made of Al- 1 leghany metal 44",v while the transmission rod in and the tube H may be made of low expanding material preferably quartz for high .temperatures (1000 F. to 1800 F.), and invar for lower tem-' peratures, thatis, below 1000 F. The open end of the quartz tube I I is rigidly mounted in the head 8 in any suitable manner, but as herein 5 shown it extends through an opening I2 in the head which opening communicates with a threaded recess in the front of the head. A threaded bushing I3 is screwed into the recess to compress packing material l4 so that it clamps the quartz tube ll rigidly to the head. The rod 9 at one end engages the closed end of the quartz tube, while in its otherencl there is mounted the transmitting rod H) which serves to transmit longitudinal expansive movement of the rod 9v toaplug-fli. This plug is slidably mounted within the open end of the quartz tube l0 and is provided with a stud projecting beyond the front surface of the head 8.' A sleeve l'l, screw threaded into the head, encases the expanding stem section 1 to provide a protective covering 5 therefor.

The head 8 is provided with'a pair of spaced lugs l8 having elongated slots therein in which the pivot I801 a bailie support 20 is swingingly mounted. This support has a baflle plate 2| piv- 1o otally mounted thereon at 22. A coil spring 23 having one end attached to the head and the other end attached to the upper part of the baffle support 20 tends to hold this support against the lug on the plug it, while a second coil spring 15 53, passing through an opening 24 in the support and having its ends respectively-connected to the head 8 and to the balile plate 2|, tends to hold this baille plate against the baille support until. displaced therefrom as will be hereinafter set forth. A pin 25 is mounted on the head 8 in a position to pass through the opening 24 in the baflie support and to engage the baflle plate 21 for a purpose to be described. A second pair of spaced lugs 25 which are provided on the head 8 adjacent the lugs l8, carries a nozzle support 28 on which a nozzle 29 is mounted in operative relation to the balile plate 2| on the baffle support 20.

There is attached to the head by screws 34, a a0 bracket 33 made of low expanding alloy with the upper end of its vertical arm 36 serving as an anchorage for a coil spring 35. This spring is connected to the nozzle support 28 so that it tends to move the nozzle 29 away from the battle 35 plate 2|. The vertical bracket arm 36 also provides a mounting for a capsular diaphragm 31, shown in cross-section in Fig. 1. This diaphragm is provided on its free surface with a stud.38 against which the nozzle support 28 rests as a 40 result of the tension exerted thereon by the spring 35. The interior of the capsular diaphragm 31 communicates with a pressure fluid' conduit 39 connected, in turn, to the branch conduits 40 and 42. Branch conduit 40 extends to 45 the air relay or pilot valve 4|, while branch conduit 42 communicates with the Bourdon spring 23 of a recording device or a combined recording and regulating device R. The opening in the nozzle 29 communicates with the pressure fluid conduit 43 terminating in capsular diaphragm 44 which diaphragm operates the stem 45 of the ball valve of the air relay 4|. 'A source of pressure fluid such as compressed air, is supplied through the conduit 46 and the branch conduit 56 41 to the air relay 4|, while the branch conduit 49 connects the supply conduit 48 through a constriction 49 to the conduit 43.

Since the temperature of the head will vary greatly in accordance with surrounding temperature conditions, it is necessary to provide temperature compensation for certain of the parts supported on the head. The diaphragm 31 is most susceptible to temperature changes since its modulus of elasticity will decrease roughly 10% for a temperature change from 0 C. to 300 C., the variation being practically related to the temperature change. Since the need for compensation arises chiefly from the fact that the elastic constant of the material of diaphragm 31 changes with temperature in such a manner that there is an increased deflection due to a temperature increase that is approximately proportional to the product of the pressure in the diaphragm and the temperature change, the compensation may be eifected by varying the ratio of the lever arms of the support 20 in proportion to the temperature change. This means that if the instrument temperature is low, the support 20 moves less than if the instrument temperature is high,

for a given temperature change at the sensitive element 9. This corresponds to the change in the motion of diaphragm 31 for a definite pressure change corresponding to the temperature change with the result that the compensating action is satisfactory. The specific construction for effecting this result includes an arm 52 which is pivoted at one end at 55 on the vertical bracket arm 36, while the other end of the arm 52 is provided with a roller 5| which contacts with the lower portion of the bailie support 20. The arm 52 rests on the upper end of the pin 58 of high expanding alloy, which pin is mounted in the bracket 33. Since the bracket 33 is made of low expanding alloy, as the temperature of the head increases, the pin 55 will expand and thereby lift the free end of the arm 52 moving the roller 5| thereon, upward on the baflle support 29. This movement of the roller 5| upward on the support 20 will shorten. the lower lever arm of the support (that is,'the portion of the support between roller 5| and the lug on plug It) as the temperature of the head increases. Conversely, the mentioned parts will cause the roller 5| to move downward on the support 29, to lengthen its lower lever arm as the temperature of thehead drops. If the material of the bracket 33 and the pin 56 are properly selected and if the parts are properly proportioned, the mentioned temperature efiect of the parts supported on the head will be compensated for.

The operation of the thermometer of the present invention is as follows: If the stem section 1 is subjected .to an increase in temperature, the rod 9 of high expanding alloy will expand, while the relatively inert quartz tube II will expand only a negligible amount. As the rod 9 expands, since its free end engages the closed end of the quartz tube, the expansion eifect of the rod 9 will be transmitted by the quartz transmission rod ID to the plug Hi. The lug on this plug will engage the bafiie support 20 and move it counterclockwise so that the baille plate 2| approaches the nozzle 20. It will be understood that compressed air from a source (not shown) is normal- 1y supplied through the conduit 46, branch conduit 48, constriction 49 and conduit 43 opening into the nozzle 29. Therefore a stream of com-- This movement of the pen arm will record the temperature change on the chart 53 which is rotated by any suitable timing mechanism (not shown). .As the pressure in the conduit 39 decreases, the diaphragm 31 will tend to contract thereby permitting the spring 35 to withdraw the nozzle support 29 and the nozzle 29 slowly away from the bailie plate 2|. The action of the diaphragm 31 tends to compensate for variations in pressure of the supply of compressed air and for sticking of the air relay 4| so that this diaphragm forms a part of a very eflicient transmission system between the stem section and the Bourdon spring.

On a drop in temperature about the stem section 1, the high expanding alloy rod 9 will contract and by means of its transmitting rod ID will withdraw the plug l6 toward the right of Fig. l. Springs 23 and 59 will cause the baiiie support 20 and the baiile plate 2| to recede from the nozzle 29 in following the movement of the plug. This will result in a drop in the air pressure in the conduit 43 with the result that the diaphragm 44 will contract tending to open the air relay 4|. The remaining operations are the reverse of those just described in the case of a rise in temperature.

It is important in a thermometer designed for use at high temperatures to provide an arrangement by which it is self-checking, that is, it becomes possible to check the accuracy of the thermometer at room temperature. This self-checking is effected in the present thermometer by means of the pin 25 and its cooperation with the baiile plate 2| in modifying the action of the device. Thus as the temperature falls to the lower portion of the range of the thermometer, the baflle support 20 moves in a clockwise direction away from the nozzle 29 so that the baflle plate 2| will finally engage the pin 25. The continued movement of the bathe support after pin 25 engages the bailie plate, will cause counterclockwise movement of this plate about its pivot 22. As the baffle plate recedes from the nozzle, prior to its engagement with pin 25, the airpressure in the conduit 43 will drop causing the diaphragm 44 to contract. This contraction of the diaphragm will tend to open air relay 4| so that air pressure from branch conduit 41 will build up in conduit 39 causing diaphragm 31 to expand. As this diaphragm expands, its stud 38 moves the nozzle support 29 and the nozzle 29 clockwise to their extreme right-hand position. The baffle plate in the course of. its counterclockwise movement due to its engagement with pin 25 eventually approaches near to the nozzle, now resting in its extreme right-hand position, so that the air stream emerging from the nozzle and the pressure in the conduit 43 is now varied in accordance with room temperatures. This variation in pressure actuates the air relay valve 4| as previously described to vary, in turn, the air pressure in diaphragm 31 and in Bourdon spring 64. This spring operates through the link 80 to cause the, pen arm II to record the room temperature on chart 63 in the manner already set forth.

It will be seen that the conduit 42, in addition to being connected to 'the Bourdon spring 64 of the recorder R, is connected to the Bourdon springs of instruments RI and R2 which are identical with instrument R, these last-mentioned recorders being located at points remote from the recorder R. However, this invention is not limited to the use of multiple recorders but instead, a single recorder may be employed in the device.

I claim:

1. In a device of the class described, a mounting structure, a battle support, a bame plate, and a nozzle mounted in cooperative relation on said structure, mechanism responsive to changes in temperature in a high temperature range for causing relative movement between said baiiie support and said banle plateas a unit and said nozzle, means supplementing said mechanism and functioning in response to a change in temperature in slow temperature range for moving said baille plate relative to said baille support and to said nozzle, and a pneumatically actuated means responsive to the varying space relation between said nozzle'and said baflle.

2. In a device of the class described, a head, a baille support swingingly mounted on said head, a baflleplate swingingly mounted on said support, a nozzle swingingly mounted on said head to approach and recede from said plate, means responsive to temperature changes in a high tempera- --ture range and engaging said baflle support to cause said baflle support and said baille plate to move as a unit with respect to said nozzle, a projection mounted on said head to engage said baflie plate to stop the movement of the same with respect to said support, as said support is moved by said means in response to a change in temperature in a low temperature range, whereby

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