US2444421A

US2444421A - Temperature measuring system with maximum or minimum selector

Info

Publication number: US2444421A
Application number: US566381A
Authority: US
Inventors: John P Boston
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-02
Filing date: 1944-12-02
Publication date: 1948-07-06
Anticipated expiration: 1965-07-06

Description

y 6, 1943- .1. P. BOSTON TEMPERATURE MEASURING SYSTEM WITH MAXIMUM QR MINIMUM SELECTOR Filed Dec 2. 1944 INVEN TOR.

JOHN P. BOSTON BY ATTORNEY Q2? new. we;

. Patented July 6, 1948 TEMPERATURE MAXIMUM MEASURING SYSTEM WITH OR MINIMUM SELECTOR John P. Boston, United States Navy Application December 2, 1944, Serial-No. 566,381

5 Claims.

(Granted under the This invention relates to selecting devices and more particularly to an apparatus that selects the maximum or minimum variations of potential effects, corresponding in magnitude of a condition, of a plurality of sources.

The principal object of this invention'is to provide means for selecting the maximum or minimum temperature of a plurality of thermal sources.

Another object of this invention is to provide means for selecting, indicating and/r identifying the maximum or'minimum temperature of a plurality of thermal sources.

Another object of this invention is to provide means for selecting, indicating and/or identifying, the maximum or minimum potential effect of a plurality of sources.

Another object of this invention is to provide means for selecting the maximum or minimum potential effect of a plurality of sources.

Anotherobject of this invention is to provide means for selecting the maximum or minimum potential effect from a plurality of sources and applying said potential effects to control means.

Similar devices. disclosed to date are of a type thatmere'ly indicate successively a series of temperatures of a plurality of sources, but none disclose automatic means for selecting, indicating, and identifying the maximum or minimum temperature of a plurality of sources, as provided for by this invention, and the application. thereof to a control device.

This invention is not limited to thermal indications, but obviously may be adapted to select maximum or minimum light indications, by merely substituting photo-electric generators for the embodied thermo-electric generators.

This invention will now be described with reference to the accompanying drawing, in which:

Fig. 1 is a wiring diagram in which is embodied several 3-way rotary switches diagrammatically. disclosed;

Fig. 2 is a section on switch of Fig. 1;

Fig. 3 is a' section on of Fig; 1; and

Fig. 4 is a section on of 'Fig. 1;

Distributor switch I consists of a stator housing 3 which carries fixed contacts 5, 3 and 1, circumferentially equally spaced, and a distributor arm 3 rotatively rigid with drive shaft 3 and insulated at 80 therefrom. Fixed

contacts

3, 3 and I, are" likewise insulated from line 3-3 of rotary switch line H of'distributor line 22 of selector act of March 3, 1883, as amended April 30, 1928;

housing. Distributor arm 8 successively engages said fixed contacts, thereby making and break ing successively selected relay coil circuits. Element I0 is any means that will transmit current to distributor arm 8 such as a brush engaging conductor ring Bl cast integral with arm 8. Shaft 3 is provided with cam II which actuates circuit interrupters l2, l3 and I4, thereby making and breaking successively selected lamp circuits. Rotary switch 2 consists of a non-conducting rotor is with reduced diameter portions l and i6. On the peripheries of said reduced diameter portions are mounted conductor rings l1 and II, respectively. On the outer periphery of the rotor is are mounted two

arcuate shorting bars

10 and 2|. shorting bar is substantially a complete ring except for a gap within which is mounted arcuate shorting bar 2| leaving a

small space

22 and 23, on each side thereof. Shorting bar 2| is connected to conductor ring l3 through means of conducting element 82. Shorting bar 2|! is connected to conductor ring l1 through means of conducting element 83. Brushes 24 and 25 are suitably mounted and slidingly engage with conductor rings l1 and I8, respectively. Fixed contacts 28, 21 and 28, circumferentially equally spaced, and carried by and insulated from stator housing 29, slidingly engage shorting

bars

20 and 2| and cooperate therewith to make and break selected circuits. The rotor is rotatively rigid with shaft 9 through means of key 84.

Selector switch 3 consists of a non-conducting rotor 30, with reduced diameter, portions 3! and 32. On the peripheriesof said (reduced diameter portions 3! and 32 are mounted conductor rings 33 and, respectively. On the outer periphery of the rotor are mounted three rotating contacts 35, 36 and 31, circumferentially equally spaced. Rotating contact 35 is connected to conductor ring 33 through means of element 35.

, Rotating contacts 36 and 31 are connected to the stator 38 that at conductor ring 34 through means of

elements

33 and 81, respectively. Brushes 38 and 39 are suitably mounted and slidingly engage conductor rings 33 and 34, respectively. Fixed contacts 43, ll. and 42, circumferentially equally spaced, and carried by and insulated from stator housing 33, slidingly engage rotating contacts 35, 36 and 31 and cooperate therewith to make and break selected circuits. Rotor 30 is rotatively rigid with shaft 3 through means of key 38.

Distributor arm 8, rotor l9, and rotor 30 are all fixed rotatively rigid to drive shaft 3, and are all in phase relationship with each other, so the instant distributor arm 3 completes circuit through fixed contact 5, rotating contact 2| engages fixed contact 26, and rotating contact 35 engages fixed contact 40, simultaneously.

Relay switches

44, 45 and 46, and their associated

thermocouples

41, 48 and 49, respectively, are connected to switches I, 2 and 3 by circuits as hereinafter described.

Relay operating coils 50, 5| and 52 are connected in parallel to battery 53, with one side of each of said parallel coil branches being completed through 3-way distributor switch The function of these circuits is primarily to energize said relay coils.

The 3-way distributor switch I is shunted through moving

contacts

54, 55 and 56, with one side of each of said shunts being completed hrough relay coils 59, 5| and 52, respectively. Shunt

contacts

54, 55 and 56 are secured to

relay moving contacts

69, 6| and 62 of

relay switches

44, 45 and 46, through insulation means 51, 56 and 59, respectively. As a result thereof, the

shunt contacts

54, 55 and 56, are closed simultaneously with the relay moving contacts 60, 6| and 62, respectively, and the relays are held closed by these shunt circuits after the selector switch arm has left its primary energizing contacts 5, 6 and 1, respectively. Said shunts comprise

movable contacts

54, 55 and 56 and fixed contacts 9|, 94, 96, respectively, circuited across distributor switch I.

Relay operating coils 50, 5| and 52, are shorted-out through selector switch 3, with one side of each of said shorting-out circuits being completed through said 3-way selector switch 3. A galvanometer 53 is connected between selector switch 3 and the relay coils. The function of the galvanometer in this circuit is merely to act as a single pole double throw switch by utilizing the deflection of its needle to make a circuit contact to the left or right. Fixed contacts 19 and 95 coact with deflecting needle 18 to perform said switching action. Said deflection is responsive to the action of the separately energized coil of the galvanometer. These circuits and the hereafter described thermocouple circuits are completed through the galvanometer and cooperate to effectuate an automatic shorting-out of the relays.

Incandescent identifying

lamps

64, 65 and 66, are connected in parallel to relay operating coils 50, 5| and 52, respectively, with one side of each of said parallel lamp branches being completed through distributor circuit breakers 2, l3 and II, respectively. It is understood that any type of signalling means, other than incandescent lamps, can be used.

The thermocouple circuit consists of

thermocouples

41, 46 and 49, connected to the normally open movable contacts, or armatures 14, 60, 15, 6|, 16, 62, of

relays

44, 45 and 46. Armatures 14, and 16 are connected to the constantan side of their associated thermocouples; and armatures 60, 5| and 62 are connected to the iron side of their associated thermocouples. Said relays fixed

contacts

89, 90, 92, 93, 91, 98, with the associated armatures and thermocouples complete a circuit in parallel, for selection purposes, across the temperature indicating device 61, the galvanometer moving coils, and the 3-way rotary switch 2, in series.

Resistors 69, 1| and 13 should be of a magnitude that prevents excessive current from flowing through the deflecting needle contacts 19 and 95.

The minimum temperature may be selected by reversing the connections to the coils of galvancmeter 63. This is simply reversing the direction of current flow through thegalvanometer coils for a given temperature couple, and the resulting reverse action of the galvanometer needle rejects the relay contacting the higher temperature thermocouple rather than that of the lower temperature thermocouple.

Thus far, this disclosure covered a means of selecting and indicating the maximum temperature of a number of thermal sources. The same circuit may be expanded to include temperature control by replacing the temperature indicating instrument 61 with a maximum-minimum temperature control instrument as is manufactured by Weston. Such a control device could be used to maintain the hottest cylinder of an air-cooled aircraft engine within certain temperature limits by actuating the cowl fiaps. There are, of course, control applications other than for aircraft engines. The principle for other uses would be the same, however, the details would be dependent on the method of regulating the flow of the cooling medium.

Operation Any plurality of thermocouplescan be used,

but for purposes of this description three thermocouples will be considered. As the distributor arm 8 engages contact 5, for the first sampling, relay coil 50 becomes energized by battery 53 and actuates relay 44 moving contacts 14 and 65 to a closed position with fixed

contacts

69 and 66. The circuit by which relay 44 is actuated to a closed position is traced as follows: battery 55, element Ill, distributor arm 6, fixed contact 5, resistance 69, relay coil 60, and back to battery 53. When the relay is closed it is held closed after the distributor arm breaks its primary energizing contact because the distributor became shunted through movable contact 64 engaging fixed contact 9| simultaneously with actuation of relay 44. Said shunt comprises movable contact 54, fixed contact 9|, and resistor 65 circuited across distributor switch The circuit by which relay 44 is held closed is traced as follows: battery 53, movable contact 54, fixed contact 9|, resistor 69, relay coil 50, and back to battery 53.

Thermocouple-identifying lamp 64 becomes connected in parallel with relay coil 50 through breaker l2 mounted on distributor switch I. This identifying lamp 54 is lit during the time its associated relay 44 is closed, except for the small period that the distributor arm 5 is contacting, at whichtime cam I lifts the breaker l2 and opens said identifying lamp circuit. (The identifying lamp associated with the higher thermocouple will remain lighted, while the lower temperature thermocouples identifying lamp will be rejected immediately upon being introduced into the circuit, as will be hereinafter more fully described.)

The closed relay contacts allow the thermocouple 41 current to energize the temperature indicator 61 and galvanometer 63 circuit through the engagement of rotating contact 2| with fixed contact 26 of rotating switch 2.

The temperature indicating instrument 61 remains in circuit with the selected thermocouple 41, after rotating contact 2| breaks with fixed contact 26, through means of conductor line 11 and the connected shorting bars l1 and 20 of rotary switch 2, until the next sampling is effected, except for a negligible period of time represented by gap 22. (The temperature reading I fully explained.)

The moving coil of galvanometer 48 is in circuit with the thermocouple for onlythe small interval of time that rotating contact 2| is successively engaged with fixed contacts 25, 21 and 25. At other times the galvanometer coil needle 18 is in a free vertical position ready to respond to the next selective action.

As the distributor arm 5 moves to the next contact for the second sampling, and engages contact 6, relay coil 5| is also battery energized and actuates relay 45 moving contacts and I to a closed position with fixed

contacts

52 and 55. When relay 45 is closed it is held closed, aiter the distributor arm 8 breaks its primary energizing contact 5, because the distributor- I became shunted through moving contact is engaging fixed contact 94 simultaneously with actuation of relay 45. Said shunt comprises movable contact 55 and fixed contact 54, cirouited across distributor switch i. The closing of relay moving contacts'15 and 6| connects thermocouple 48 in parallel with thermocouple 41 through the engagement of rotating contact II with fixed contact 21, and allows the thermocouple 48 current to additionally energize the temperature indicator 81 and galvanometer 63 circuit. The parallel association of thermocouples 41 and 48 continues for but a very short interval of time, for

ately by the action of galvanometer needle 18 explained in the following paragraph,

The direction in which the galvanometer needle 18 is deflected depends on which of the selected thermocouples is at the higher temperature. Suppose thermocouple 48 is at the higher temperature, then the galvanometer needle 18 will move to the left, make contact with galvanometer fixed contact. 19, and short out the hold-down coil 50 of relay 44, through engagement of rotating contact 31 and fixed contact 40. Thus relay 45 remains closed and relay 44 is thrown open thereby rejecting thermocouple 41. The temperature-indicating device 61 will now indicate the temperature of the larger and only remaining thermocouple in circuit with the saidv temperature-indicating device, through means of conductor line 11, the connected shorting bars l1 and ill, and fixed contact 21, until the next sampling is eilected. The left or right thermocouple 45 is the hotter of thepair, its current will dominate the circuit and be directed through the galvanometer il in a direction that .one or the other is shorted out almost immediwill cause the needle to deflect to the left and reject the lower temperature thermocouple 41 from circuit association with said higher temperature thermocouple 48. The remaining thermocouple 48 then bucks thermocouple 45 in the same manner when the contact 2| moves to contact 28, relay 48 being closed by the action of rotary switch I. Thermocouple identifying lamp 65 becomes connected in parallel with relay-coil 5| through breaker 15 mounted on distributor I. This identifying lamp 65 also became lighted when its associated relay 45 was closed, except for the small period of time that the distributor arm 8 is contacting at which time cam H lifts the breaker l3 and opens said identifying lamp circuit. However, one or the other of said lamps will be rejected depending upon which of their associated thermocouples is at the lower temperature. This rejection is eflectuated by the galvanometer needle 18 action hereinbefore described, shorting out hold-down coil 50 and its associated identifying-lamp 64. The light circuit is opened during the interval that the distributor is contacting to prevent extra lighting of a lamp when each relay is sampled. The function of the lamp circuit is to identify only the thermocouple that is at the highest temperature. Thus relay 4!; remains closed, thermocouple identifying lamp is lighted and the temperature indicating device 81 will now read the temperature of thermocouple 45, it being the larger temperature of the two thus far sampled thermocouples.

I-Iad thermocouple 41 temperature been greater than thermocouple 45 temperature, the galvanometer needle 18 would have been deflected to the right, make contact with galvanometer fixed contact 85, thereby kicking out" relay 45, and consequently thermocouple 48. Consider the part or the cycle before, during, and after, the selection period when thermocouple 45 is compared with thermocouple 41. Contact 2| has left contact 26 and is approaching contact 21.

the sake of descriptive convenience) of thermocouple 41 is connected to contact 26, and through rings 20 and I1 to the right terminal of galvanometer 65. No current flows through the galvanometer because contact 2| is out of the cirdirection in which the galvanometer needle 18 the constantan side to the iron side through the hot junction. These thermo-electric generators can be incorporated in circuits so that they either buck each other or reinforce each other. In this cuit. Meter 61 is indicating the temperature of thermocouple 41, connection to the constantan side being through contact 26, rings 25 and 11, wire 11, and the wire joining 11 to the right terminal of meter 61. Arm 8 moves on to contact 5 to close relay '45, and simultaneously, conparticular embodiment, the thermocouples are connected in circuits so that they buck each other during "the comparing interval. Therefore, since the hottest thermocouplelgenerates the greatest current, and since it bucks the lesser current from the colder thermocouple, the current from the hottest thermocouple will dominate the circuit, and its direction will determine the polarity of the galvanometer 63 coils at any given tact 2i forms an electrical connection with contact 21, which action connects the constantan side of thermocouple 48 to the left terminal of galvanometer 83 through relay arm 15, relay contact 92,

contacts

21 and 2|, ring l5, and contact 25. The constantan side of thermocouple 41 is still connected to the right terminal of galvanometer 53 through wire 11, rings i1 and 25, contact 26, and relay 44. Now the energizing coil of galvancmeter 55 has the constantan side of thermocouple 41 connected to its right terminal and the constantan side of thermocouple 45 connectedto its left terminal in bucking relation, since current flows from the constantan side to the iron side through the hot junctions of both thermocouples. A current now flows through galvanometer 53, the direction of which is de:

Relay '44 is closed and the constantan side (so called for termined by which thermocouple, 41 or 48, is at the higher temperature. Suppose 48 is higher. The polarity of the galvanometer is so arranged that needle 18 moves to the left under these circumstances, and relay 44 is opened through the action of needle 18 making connection through contacts 18, 39, ring 34, contacts 81 and 40 to resistor 89. If thermocouple 41 had been higher, the needle 18 would have moved to the right and shorted. out relay 45, through contacts 88, 38, ring 33, contacts 85 and 4| and resistor 1|. But 48 is the higher, and relay 44 has opened. Now the right terminal of galvanometer 63 is no longer connected to the constantan side of thermocouple 41, and for a brief instant until contact 21 moves away from contact 21, galvanometer O8 is in series with the constantan sides of thermocouple 48 and that of meter 61 and deflection of the needle 18 to the left is maintained until 2! leaves 21. Themeter 61 takes up the'correct reading of thermocouple 48 when ring 20 moves to contact 21, and maintains it until the next comparison period when thermocouple 48 is introduced into the circuit. When contact 2| leaves contact 21, galvanometer 83 is out of the circuit and remains so until contact 2i touches contact 28.

It should be further understood that coil 50 is not shorted out by the action of the galvanometer needle 18 when thermocouple 41 is connected. If the instrument is turned on with rotary switches l, 2, and 3 in a position where relay 44 is the first to be energized, the first temperature comparison will be between thermocouple 41 and the cold Junction thermocouple of meter 81. Unless circumstances are very unusual, thermocouple 41 will be at a temperature higher than that of the thermocouple of meter 1. The needle will move to the left (see below), and the action will be such as to connect one side of resistors 1i and 13 to the battery but with coil 50 not shorted out. Thus relay 44 would remain closed until rejected as low in the subsequent normal comparison periods with

thermocouples

48 and 49; The statement that the needle would be deflected to the left because thermocouple 41 is at a higher temperature than the thermocouple of meter 61, may appear in conflict with a statement in the preceding description of the specification, but that it is not the case. In the latter instance, the constantan side of thermocouple 41 was connected to the right terminal of galvanometer 63 due to the position of switch 2; in other words, contact 26 was bearing on ring 20 since II was contactin 21. It is the purpose of switch 2 to insert the galvanometer into the circuit so that the left terminal always is connected to the constantan side of the thermocouple last brought into the circuit. This is necessary to prevent the action or a higher thermocouple rejecting itself.

As distributor arm 8 moves on fixed contact I. the third sampling relay 46 closes, and again the galvanometer needle 18 kicks out" the relay associated with the lower temperature thermocouple, and so on around to relay 44 again. Thus, only the thermocouple having the maximum temperature will be finally selected, identified by its associated lamp, and its temperature indicated on the temperature indicating instrument. The operation is continuous and the speed of the cycle depends on the speed of the driving motor which is limited only by the time required to operate the relays and galvanometer.

If it should happen that two or more temperatures are the same, and higher than the remainder oi the temperatures, the galvanometer will not release the relays of the two or equal highest thermocouples, and the lamps will indicate this condition by identifying both said sources;

11 a flickering of the needle of the temperature-indicating meter, during the short interval when two thermocouples are being compared, is objectionable. a mechanical or electrical needle locking device may be used durlng that interval.

11' it is desired to indicate, select, and identify the minimum temperature, it may be eii'ected by reversingthe connections to the galvanometer 88 coils. This is simply reversing the direction of current flow through the galvanometer coils for a given temperature couple, and the resulting reverse action of the galvanometer needle rejects the relay contacting the higher temperature thermocouple rather than that of the lower temperature thermocouple.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is: l

1. An apparatus of the character described, comprising: a source of current; a plurality of electromagnetically operated switch means; a first mechanism for successively and individually associating said source of current with the electromagnetic operatin means of said switch means; means controlled by said switch means when operated for continuing said association independent oi' said mechanism; a plurality oi means for producing electrical efiects respectively corresponding with variations in magnitudes of a plurality of conditions; common means for making measurements of said electrical effects; deflecting means responsive to electrical efiects; a second mechanism acting synchronously with said first mechanism for severally associating said electrical effects producing means with said measurement making means through the operated switch means and for associating temporarily two of said electrical effects produoing means in opposition to said deflectin means through the operated switch means; and a third mechanism acting synchronously with said second mechanism during said temporary association for providing short circuits for the operating means of said two switch means then eflective on said effect producing means through said deflecting means in oposite directions, whereby one of the switch means will be released depending upon the direction of deflection oi the deflecting means, and whereby only one of the effect producing means will remain in association with the measuring means, and indicatin means individual to and controlled by the operative condition of the electromagnetically operated switch means.

2. The apparatus as set forth in claim 1, in which said means for producing electrical effects is a thermocouple.

3. The apparatus as set forth in claim 1 in which said deflecting means is a galvanometer.

4. An apparatus of the character described, comprising: a source of current; a plurality of electromagnetically operated switch means; a first mechanism for successively and individually associating said source of current with the electromagnetic operating means of said switch means; means controlled by said switch means aaeaeai when operated for continuing said association independent of said mechanism; a plurality of means for producing electrical eiiects respective ly corresponding with variations in magnitude of a plurality of conditions; common means for making measurements of said electrical efiects; deflecting means responsive to electrical effects; a second mechanism actlngsynchronously with said first mechanism for severally associating said electrical efiects producing means with said measurement making means through the operated switch means and for associating temporarlly two of said electrical efiects producing means in opposition to said deflecting means through the operated switch means; and a third mechanism acting synchronously with said secand mechanism during said temporary association for providing short circuits for the operating means of said two switch means then effective on said effect producingmeans through said defleeting means in opposite directions, whereby one of the switch means will bereleased depending upon the direction of deflection of the deflecting means, and whereby only one of the effect producing means will remain in association with the measuring means.

5. An apparatus of the character described, comprising: a source of current; a plurality of electromagnetically operated switch means; a first mechanism for successively and individually associating said source of current with the electromagnetic operating means of said switch means; means controlled by said switch means when operated for continuing said association independent of said mechanism; a plurality oi means for producing electrical efiects respectively corresponding with variations in magnitude of a plurality of conditions; common means for making measurements of said elec trical effects; deflecting means responsive to electrical effects; a second mechanism acting synchronously with said first mechanism for severally associating said electrical eiiects producing means with said measurement making means through the operated switch means and for associatin temporarily two of said electrical effects producing means in opposition to said defleeting means through the operated switch means; and a third mechanism acting synchronously with said second mechanism during said temporary association for providing short circuits for the operating means of said two switch means then effective on said efiect producing means through said deflecting means in opposite directions, whereby one of the switch means will be released depending upon the direction of deflection of the deflecting means, and whereby only one of the effect producing means will remain in association with the measuring means, and indicating means individual to and controlled by the operative condition of the electromagnetically operated switch means.

JOHN P. BOSTON.

REFERENCE$ CKTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,496,101 Schmitt June 3, 1924 1,775,540 Taylor Sept. 9, 1930 2,266,185 Fillo Dec. 16, 1941