US705187A - Multiplex electric thermometer. - Google Patents

Description

' Patented July 22, 1902.

A. zELENY. MULTIPLEX `ELECTRI THERMOMETER.

lApplication filed Jan. 20, 1902.)

3 Sheets-Sheet 2.

(No Moden.)

Patented July 22, |902.

4 No. 705:,la7.

A. zELENY. vMULTIPLEX ELECTRIC THERMOMETER.

.Application med Jan. 2o, 1902.

3 Sheets-Sheet 3.

(No Model.)

mi if Q* TH: Noam s PETERS co, PHOTO-LMAO. wAsr-nn'cron, o4 c,

UNITED STATESk ANTHONY ZELENY, OFv MINNEAPOLIS, TO O.-E. THAYER, OF MI PATENT Orrrou.

MINNESOTA, ASSIGNOR OF ONE-HALF NNEAPOLIS, MINNESOTA.

M ULTIPLEAX ELECTRIC THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 705,187, dated July 22, 1902. Application filed January 20,1902. Serial No. 90,402." (No model.)

To @ZZ whom it may concern,.-

Be it known that I, ANTHONY ZELENY, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Multiplex Electric Thermometers; and I do herebydeclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has for its object to provide improved means for readily determining at a reading-station the temperature at various distant points; and to this end it consists `of the noveldevices and combinations of devices hereinafter described, and defined in the claims.

My improved device for accomplishing the above result may very properly be designated as a multiplex electric thermometer. It involves the use of a plurality of thermo-electric circuits or couples having individual thermo-electric junctions and a common thermoelectric junction. The common thermo-electric j unction-ispreferably located at or in the immediate vicinity of the reading-station, and as its temperature is either known or capable of beingreadily determined it may be designated as the known-temperature junction. The individual junctions are located at various distant points, and as their temperaturesare to be determined by the use of the instru-- ment they may be properly designated as the unknown-temperature junctions.

A galvanometer or reading instrument is connected in oneof the leads to the common or known-temperature junction, and a switch is also provided whereby any thermo-electric circuit or couple may be closed into circuit withthe common'thermo-electric j unction and common galvanometer. Otherwise stated,by means oi the switch the common or knowntemperature junction may be balanced against or made to react against any one of the individual or unknown-temperature junctions, and the galvanox-neter will indicate the temperature at such unknown-temperature oru distant junction. The system involves other novel and important features of construction,

. This improved multiplex electric thermometer is capable of a very wide range of different uses; but in the drawings it is illustrated as applied for determining temperature at 55 different levels in a series of storage-bins, such as are used in grain-elevators.

In the drawings like characters ind icate like parts throughout the several views.

Figure l is a view principally in diagram, 6o but with some parts shown in vertical section, illustrating my improved device applied as aboveindicated. Fig. 2 is a detail view in plan, showing the switch and switchboard on an enlarged scale.- Fig. 3 is a vertical section 65 outhe'line 3 3 of Fig. 2. Fig. 4 is a vertical section showing in detail a portion of one of the incasing tubes for the so-called individual or unknown-temperature junctions. Fig.

5 isa view corresponding to Fig. 4, but illus- 7o tratinga slightly-modified construction of the said tube. Figs. 6 and 7 are also detail views in vertical section, illustrating modified constructions of the incasing tubes and of the thermo-electric junctions supported thereby. 7 5 The numeral l indicates grain-storage bins.

. The numeral 2 indicates a switchboard having contact-pins 3. A switch-lever 4, pivoted to said switchboard 2, is provided at its free end with a sliding contact-head 5, which 8o coperates with the contact-pins 3 and, as shown, is adapted tobe frictionally held in its set position by a spring-pressed pin 6. (Best shown in Fig. 3.)

The numeral 7 indicates a suitable galva- 85 nometer or other reading instrument which is sensitive to current-flow.

The numeral 8 indicates the common thern10-electric junction, and the numeral 9 indicates the individual thermo electric j unc- 9o tions, the former of which is located at the reading-station or in the vicinity of the galvanometer and switch and the latterof which are distributed at different points within the bins l. In the illustration given these ther- 9 5 ino-electricj unctions 8 and 9 are formed of copper and German-silver wires twisted and soldered together. Theommon or known-temlerature thermo electric junction S is arra`n`ged to react against orfact in opposition to roo any of the individual or unknown-temperaall of which will hereinafter appear.

ture junctions 9 with which it is coupled.

This will be apparent by noting that the copper wires 10 and 10l are indicated by full lines, while the German-silver wires 11, 11a, and lllareindicated bydottedlines. Thesaid wires 10 extend one from each junction 9 to a different pin 3 of the switchboard 2. The sliding contact-head 5 is connected to the copper member of the common junction 8 by the wire 10a, and the galvanometer 7 is shown as interposed between the sections of said wire 10i. The German-silver member of said common junction 8 is connected to the Germansilver member of all of the individual or unknown-temperature junctions 9 by the common German -silver return-wire 11, having branches 11n.

The numeral 12 indicates a resistance-coil afforded by what is known as a low-temperature-coefcient coil or wirethat is, a coil or body of wire whose resistance remains approximately constant under varying temperatures. The coil 12 is shown as interposed between sections of the return-wire 11, in the vicinity of the common junction 8,and its connections therewith areindicatedat 12a. These connections 12a to soine extent constitute thermo-electric junctions, and to prevent the same from interfering with the proper actions between the junctions 8 and 9 it is essential that they be kept at the same temperature, and hence equally balanced. For this reason the said coil 12 is preferably placed within a tight box or inclosing compartment 13. The thermo-electric junction 8 is also shown as placed within a box or closed compartment 14, into which also the lower or bulb end of an ordinary thermometer 15 is placed.

The numeral 16 indicates a thermo-electric junction of the same character as those described, but which is located at a distant point from the reading-station and is adapted to be used for testing purposes-that is, for testing the accuracy of the system. The German -silver member of this junction 1G is shown as connected to the return-wire 11 by a German-silver wire 111'. The vcopper member of said junction 1G is connected to a pin onthe switchboard 2 by a copper wire 10b. The said junction 1b is also preferably' inclosed in a tight box 17, into which also the bulb or lower end of an ordinary thermometer 18 is placed. This testing-junction 16 and its connections are not an essential feature of my invention.

To protect thewires and the junctions 9 from the grain or other material with which the bins will be filled, they are preferably placed within metal pipes or tubes, as shown at 19 in Fig. 4. These tubes or pipes 19 will be properly supported within the bins, preferably from the overhead bin-supports. (Not shown.) To confine the air surrounding the junctions 9 and prevent the circulation thereof upward through the pipe 19, plugs 2O are shown as placed within the said pipes.

In the construction illustrated in Fig. 5 the pipe 19 is provided with laterally-projecting thimbles 21, in which the junctions 9 are inclosed. The outer ends of the said thimbles 21 are shown as closed by caps 22, while their inner ends are shown as closed by plugs 23. The construction illustrated in Fig. 6 is substantially the same as that illustrated in Fig. 4, the only difference being that the wires 10 and 11L are directly connected to form the junctions 9.

The construction illustrated in Fig. 7 involves the pipe 19 with projecting thimbles 21; but in this construction the thermo-electric junctions 9 project through and depend from said thimbles 21, so that they may come in direct contact with the grain or other materials stored in the bins. These depending junctions 9 and their leads are of course insulated from the pipe 19 and thiinbles 2l. As shown, insulating-clamps 24, applied to said thimbles 21, hold the leads of the said junctions. Instead of the metal pipes 19 hollow exible cables, of wire or other suitable material, may be used. It will also be understood that the wires or leads 10 and 11 where they extend between the incasing tubes 19 and the switchboard 2 may be protected in any suitable Way-as, for instance, by being formed into a covered cable. It will be noted that by the use of the switchboard and switch illustrated a very large number of distant individual or unknown-temperature junctions may be coupled into circuit with the common junction 8. In the drawings only six of these individual junctions 9 are shown, and hence but six of the switchboard-pins 3 are used in connection therewith.

The operation of the device described will be substantially as follows: For one illustration we will assume that the common junction 8 is kept at the constant temperature of melting ice-'to wit, 32 Fahrenheit. Now it is evident that if the temperature of the particular individual junction 9 which is coupled into circuit with the said common junction 8 is also at the temperature of melting ice there will be no current-flow through the closed thermo-electric circuit or couple, for

the reason that the two thermo-electric junctions 8 and 9 are balanced against each other. If, however, the temperature of the two junctions thus closed into circuit are different, there will be a iiow in the one direction or the other through the closed thermo-electric circuit or couple, and this flow will be indicated by the galvanometer. So far as my present invention is concerned the galvanometer may be made to read either in degrees directly or in volts or amperes, which are capable of being translated into degrees. However, it is my intention to use in connection with this system a galvanometer of the general character set forth and claimed in a companion application filed by me of even date herewith, entitled Galvanometer. By the use of my improved galvanometer the IOC) lor;

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temperature of a distant individual junction 9 may be directly read even where the temperature of the common or known junction S is permitted to vary. The resistance or lowtemperature-coefticient coil l2 makes negligible errors in readings due to different lengths of various circuits vand to change of resistance in the Wires of thel system due to varyingtemperatures. Furthermore,the said coil serves to reduce to convenient length the divisions on the scale.

It will of course be understood that any suitable combination of metal wires or leads may be used to form the thermo-electric j unctions. For instance, iron and copper might be used in some cases.

As already indicated, the device is capable of a very wide range of use. It is of course especially serviceable for indicating the te mperatures at various inaccessible points, such as within bodies or piles of grain contained in bins or coal contained in the bunkers of vessels or in storage.

The device is also very serviceable for indicating the temperature at various distant points, which while accessible can be much more conveniently read from a common point or station, such as the temperatures 'in the various parts of cold-storage plants.

The device is of course capable of a large range of modification as to details of construction and arrangement of parts within the scope of my invention as herein claimed. It will of course be understood that various other combinations of metals may be used for the thermo-electric junctions and wires of the couples or thermo-electric circuits.

The expression galvanometer7 is herein used in a very broad sense to include any measuring instrument which is sensitive to an. electric current or to a difference of potential.

The expression switch is herein used in a broad sense to cover all devices capable of use to open and close the various circuits.

What I claim, and desire to secure by Letters Patent ot' the United States, is as follows:

i l. The combination with a galvanometer and a switch, of a plurality of thermo-electric circuits having individual thermo electric junctions-and a common thermo-electric j unction, which common junction, by said` switch, may be connected withany fopposingt-individual junction, to complete the thermo-electric circuit, substantially as described.

2. The combination with a plurality of thermo-electric couples having a common lead of a dierent metal than that of the individual leads, of a common galvanometer and a switch for closing any couple into circuit with said galvanometer, substantially as described.

3. The combination witha switch and a galvanometer, of a plurality of thermo-electric circuits having individua] thermo -electric junctions and a common thermo-electric j unction, which common junction is in one of the leads to said galvanometer and, by said switch, is adapted to be connected with any opposing individual junction, to complete the thermo-electric circuit, substantially as described.

4. The combination with a galvanometer and a switch, of a plurality of thermo-electric circuits having a common return-lead and provided with individualnthermo electric junctions anda common thermo-electric j unction, which common junction, by said switch, may be connected with any opposing individual junction, to complete the thermo-electric circuit, substantially as described.

5. The combination with a galvanometer and a switch, of a plurality of thermo-electric circuits having individual thermo-electric junctions, a common thermo-electric junction, and a resistance coil or device in oneof the leads to said commonj unction, which common junction, by said switch, may be connected with any opposing individual j unction, to complete the thermo-electric circuit, substantially as described.

6. The combination with a galvanometer and a switch, of a plurality of thermo-electric circuits of different length and resistance, having individual thermo-electric junctions, a common thermo-electric j unction and a common low-temperature-coeficient resistancewire, which common j unction, byA said switch,

Vmay be connected with any opposing individual junction, to complete the thermo-electric circuit, substantially as described.

'7. The combination with a plurality of therino-electric circuits and a switch, of a common branch of high resistance including a galvanometer, which common branch, by lsaid switch, is capable of being connected into any one of the thermo-electric circuits, whereby said circuits, when successively closed, have practically equal resistance enabling equal differences in temperature to produce, in the said various circuits, equal deiiections on the common galvanometer, substantially as described. V

In testimony' whereof I affix my signature in presence of two witnesses.

ANTHONY ZELENY. wWitnesses:

` ELIZABETH KELIHER,

F. D. MERCHANT.

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