US1664965A - Apparatus for temperature control - Google Patents

Description

' A ril 3, 1.928. 1,664,965

1 A. BONDS APPARATUS FOR TEMPERATURE CONTROL Filed May 19. 1926 2 sheets-Sheet 1 Qhwentor:

$5567 BOA/05, v

Aprifi 6, E928. 1,664,965

A. BONDS APPARATUS \FOR TEMPERATURE CONTROL Filed May 19. 1926 2 Sheets-Sheet 2 fitnesses as applied to a Patented 3, 192 8.

ALBEBT BONDS, OF CLEVELAND, OHIO.

APPARATUS FOR TEMPERATURE CONTROL.

Application filed May 19, 1926. Serial No. 110,303.

This invention relates to apparatus for maintaining a constant temperature at a predetermined point in a heated receptacle containing gaseous or liquid matter, molten metal and the like, and has for its object the provision of a sensitive control of the temperature, and the elimination of what is commonly called lag from the temperature control. 7 p

The invention will be described in detail spelter bath for galvanizing Wire, although itwill be understood that itsuse is in nowise limited to controlling the temperature of a spelter bath since it may be used to control the temperature of many other objects.

In the drawings:

Figure 1 is a diagrammatic plan of a temperature control apparatus applied to a galvanizing pan, for carrying out the novel method of this application.

Figure 2 is a side elevation of the burner regulating mechanism.

Figure 3 is a sectional elevation on the line III-1H of Figure 2.

Figure L is a top plan of the contact and depressor elements of the relay instrument.

Figure is a transverse section through the elements of Figure 1.

Referring more particularly to the drawings, the numeral 2 designates a spelter-pan containing the molten spelter through which wires 3 are continually passed to be coated. The spelter-pan 2 isadapted to be heated by gas or oil burners 4 adjacent the entrance end of the pan. The burners 4 may be of any usual design and receive air from an air main 5 and fuel from a fuel supply pipe 6 having branches? leading to the separate burners. The branch pipes 7 are each provided with valves 8 to control the feed, of fuel to the respective burners.

A burner control or regulating apparatus is provided for regulating the fuel and air supply to the burners. This apparatus is of standard commercial design obtainenergized by able on the open market and, therefore, will i only be diagrammatically. illustrated and generally described. ing apparatus comprisesa main drive-shaft 9 having a drive ratchet-wheel 10 secured thereon at one end and having sprocketwheels 11, 12 and 13 secured thereon. No teeth are formed on a portion of the periphery of the ratchet-wheel 10, so as to limit its movement; that is, so that when this portion of the ratchet-wheel is opposite the operating pawls, to be described, the pawls will not effect a movement of the wheel, thereby providing a limit to the burn-- er operation.

The sprocket-wheel 11 is connected by a chain 11 to a sprocket-wheel 14 on a damper-s'haft 15 of a damper or valve 16 in the air main 5, so that rotation of the shaft 9 will operate the damper or valve 16.

The sprocket-wheel 12 is connected by a chain 17 to a sprocket-wheel 18 on the shaft The burner regulatof one of the valves 8, while the sprocketwheel 13 is connected by a sprocket-chain 19 to a sprocket-. wheelj20 on the other valve 8, so that rotation of the shaft 9 will also operate the fuel valves 8.

The ratchet-wheel 10 is adapted to be operated by pawls 29 and 30 carried by a'pawlyoke 31 which is pivotally mounted on a rocking-lever 32 adapted to be continually rocked by an eccentric 33 carried by a constantly driven shaft 34. A pair of solenoids 35 and 36 are mountedonthe lever 32 below the yoke 31, and are adapted to be energized to rock the yoke 31 so. as to engage either of the pawls 29 or 30 which;..due to the con- 'tinuous rocking movement .of the lever 32,

will cause a step by step rotation of the ratchet 10 and shaft 9 as long as the solenoid remains ener 'zed.

The solenoids 35 and 36am adapted to be i an electric circuit which is con-. trolled by a galvanometertype of relay instrument 37. The instrument 37 is of standard design and has a coil 38 encrgizable by While the contact a temperature controlled and adapted to deflect an electric current, indicator-needle 39 to one side or the other of a neutral point in response to the rise and fall of the temperature in the spelter-pot 2.

'The'needle 39 is adapted to move in a space between a depressor-bar 40 and a pair of contact plates 41 and 42 Which are separated by an insulated gap 43. a

The depressor-bar 40 is connected to one line 44 of the solenoid energizing circuit, plate 41 is connected by a Wire 45 to the one end of the solenoid coil 35, and the other end of the coil '35 is connected to the other line 46 of the solenoid energizing circuit. The contact plate 42 is connected by a Wire 47 to the one end of the solenoid coil 36, and the'other end of the coil 36 is connected to the line 46 of the solenoid energizing circuit.

' A solenoid coil 48 is connected to the lines 44 and. 46 and is adapted to be energized to depress the depressor-bar 40.

The ratchet-Wheel 10 is adapted to be operated by pawls 29 and 30 carried by a pawl-yoke 31 which is pivotally mounted on a rocking-lever 32 adapted to be continually rocked by an eccentric 33 carried by a constantly driven shaft 34.' A pair of solenoids 35 and 36 are mounted on the lever 32 below the yoke 31, and are adapted to be energized to rock the yoke 31 so as to engage spouse to the rise and either of the pawls 29 or 30 which, due to the continuous rocking movement of' the lever 32, will cause a step by step rotation of the ratchet 10 and shaft 9 as long as the solenoid. remains energized, .or until the smooth portion of the ratchet-wheel 10 is reached.

The solenoids 35 and 36 are adapted to be energized by an electric circuit which is controlled by a galvanomet-er type of relay instrument 37. The instrument 37 is of standard design and has a coil 38 energizable by a temperature controlled electric current, and adapted to deflect an indicator-needle 39 to one'side or the other of a neutral point in reture in the spelter-pot 2.

The needle 39 is adapted to move in a space between a depressor-bar 40 and a pair of contact plates 41 and-42 which are separated by an insulated gap 43.

The depressor-bar 40 is connected to one line 44 of the solenoid energizing circuit, While the contact plate 41 is connected by awire 45 to the one end of the solenoid coil 35, and the other end of the coil 35 is connected to the other line 46 of the solenoid energizing circuit. The contact plate 42 is connected by a Wire 47 to the one end of the solenoid coil 36, and the other end of the coil 36 is connected to the line 46 of the solenoid energizing circuit.

fall of the tempera- A solenoid coil 48 is connected to the lines 44 and 46 and is adapted to be energized to depress the depressor-bar 40. The circuit through the lines 44 and 46 is adapted to be regularly made and broken by a timed make and break device represented by the contactor 49, so that the depressor-bar 40 willbe regularly depressed.

The operation of the mechanism above described is as follows- Assuming that the needle 39 is in neutral position the depressor-bar 40 will be regularly depressed by the energization of the coil 48, Without energizing oi afiecting the solenoids 35 or 36. However, should the coil 38 be energized to move or deflect the needle to the left was to be positioned between the depressor-bar 40 and the'plate 42, When the depressor-bar is depressed, a circuit'will be completed from the line 44 through the depressor-bar 40, needle 39, plate 42, Wire 47, solenoil coil 36 and line 46, thus energizing solenoid coil 36 and rocking the yoke 31 so as to engage the pawl 29 With the ratchet-Wheel 10. The above cir cuit will continue to be made as the depressor-bar is depressed until the needle 39 is moved to the right by a changein the energization of t-hecoil 38 so as to move the needle 39 either to its neutral position or to the right between the plate 41 and dc pressor-bar 40.

When the pawl 29 is engaged in the ratchet-wheel 10, the rocking of the lever 32 will cause operation of the burner regulating apparatus. 4

Now assuming that the coil 38 be reversely energized, or its value of energization he changed. so that the needle 39 is moved to the right and between the plate 41 and depressor-bar 40, when the depressor-bar40 is depressed a circuit will be completed from the line 44 through the. depressor-bar 4U, needle 39, plate 41, Wire 45, solenoid coil 35 and line 46, thus energizing solenoid coil 35 and rocking yoke 31 so as to engage the pawl 30 with the ratchet-Wheel It). This last described circuit will continue to be made as the depressor-bar is'deprcssed until the needle 39 is moved to the left by a change in the energization of the coil 38 so as to move the needle 39 either to its neutral position or to the left of its neutral position between the plate 42 and depressor- When the pawl 30 is engaged in theratch- (t-wheel 10, the rocking of the lever 32 will cause an operation of the burner regulating apparatus in a reverse manner to that when ers and consequent desired temperature-may be had, and it is to this that my novel invention pertains.

The mechanism above described is all standard mechanism in common use and well known to those versed in the art to which this invention pertains and, therefore, will not be further illustrated or described.

The coil 38 of the galvanometer-type relay 37 is adapted to be energized by current produced by a combination of thermo- couples 50, 51 and 52. Therefore, the position of the needle 39 varies according to the current produced by these thermo-couples.

The thermo-couple is positioned at the exit end of the pot 2 at which point a constant temperature is desired to be maintained, this thermo-couple has amajor effeet on the coil 38. The thermo- couples 51 and 52 are located near the entrance end of the pot 2 close to the burners 4, one in the heated medium, and the other in the furnace or flue, respectively, and both of these thermo-couples have minor effects on the coil 38. v

The thermo-couple 50 has the prime effect on the coil 38 to cause the needle 39 to move in accordance with temperature changes at the point where the thermo-couple 50 is located toward 'or away from the gap 43. However, the thermo-couple 50 is always assisted by the other thermo- couples 51 and 52. The thermo-couple 51 intercepts the temperature changes due to the changes in the heat requirements, as for example, change in the size or speed of travel of the wires. The thermo-couple 52 quickly responds tochanges in. flue temperatures due primarily to changes in rate of heat evolution or heat supplied, and tends always to energize the coil 38 so as to quickly move the needle 39 towards or away from the gap 43, depending on whether the burners have been turned on or ofl", resulting in raising or lowering the flue temperature. The thermocouple; 52 is most sensitive so far as time is concerned, but has a small total eflect.

As the load or heat requirement varies very little, the thermo-couple 51 has little to do with the control or regulation. However,

it is essential to efi'ect a proper regulation of the pointer in response to changes in size or speed of the wires, or the addition of cold spelter.

Mathematically the control can be illustrated as follows- Let: Ld=efiect of the thermo-couple 51. Fd=efiect of the thermo-couple 52. C d='efi'ect of the thermo-couple 50.

Assume Cd= constant.

Ldrl-Fd=constant.

Then Cd+Ld+Fd=constant (or setting of the gap 43).

which will cause the needle to move. into position to make the necessary circuit to cause more fuel to be turned on. The increased fuel causes an immediate rise of temperature in the flue and increases the energization from the thermo-couple 52 so that the drop of the thermo-couple 51 is com-'- pensated for. The control is effected and normaterial change is noted at the control point or thermo-couple 50. The thermo- couples 50, 51 and 52 are connected by leads 56 and 56 57 and 57158 and 58 from the opposite sides of the respective thermo-couples through a junction or cold-end box 55 to a potentiometer unit 59.

The wire 56 from one side of the thermocouple 50 is connected to a rheostat or resistance coil 60 and a wire 61 leads from the coil 60 to the one end of the coil 38 of the relay 37. The other end of the coil 38 is connected by a wire 62 to a movable contact adapted to engage with a potentiometer resistance coil 63. ,The wire 56 from the other side of the thermo-couple 50 is connected to one end of a potentiometer resistance coil 65.

The wire 57 leadingfrom one side of the thermo-couple 51 is connected to the same end of coil 65 as the wire 56*, while the wire 57 from the opposite side of the thermo-couple 51 is connected to a movable contact 66 adapted to have a movable con-1 tact with the coil 65.

The wire 58 from one side of the thermocouple 52 is connected to the one end of the coil 63, while the other wire 58 from the opposite side is connected to a movable contact 67 adapted to have a movable contact with the coil 63.

A movable or adjustable contact 68 is connected to the end of the coil 63 to which the wire 58 is connected and is adapted to have movable or adjustable contact with the coil 65.

The potentiometer unit 59 provides for the interconnecting of the currents from the thermo- couples 50, 51 and 52. so as to obtain desired proportionate amounts of said currents and accumulating said proportionate amounts of said currents into a single current to operate the .relay 37.

By omitting or neglecting the resistances of lead wires and other necessary connectors for the sake of simplicity, in order to determine the proper design or value of potential reducers or potentiometers the 01- lowing algebraic equations and their solu- 'tions are necessary- Let C=thermo-couple 50.

L== thermo-couple 51.

Ft=approximate flue temperaturecold end deducted. 1

Cd=deflection in degrees F. caused by thermo-couple 50.

P V Ld=deflection in degrees F. caused by (m= resistance of coil 38. y thermo couple 51. gs of potentlometer Fd=deflection in degrees F. caused by Fr=t0t il resistance of otentiometer ermo-coup 1e 63 P V L8=res1stance of sections of potentiom- Lp=resistance parallel to Cr in the cire-ter 0011 65 m Parallel Quit. of thermo couple 5L Fs==res1stance of sections of potentiom- -F;o=resistance parallel to Cr in the cireter c011 63 In parallel cuitof thermmcouple 52 Ce=cold end temperature of thermo- Z=resistance coil 60 for ofisettin ef- P p fectsofthermo couples 51am 52 All resistance is expressed 1n ohms. Ct=temperatum d i d. to 1 All temperatures are expressed 1n degrees cold end deducted. Fahrenheit. Lt= approximate (load d temperature Using the above symbols the-equations are cold end de ucte as follows-- i Lp(Cr+Z+Fs) Lp Cr Z Fs Cr 4 i I Cr+Z+Fs Lp(Cr +Z+Fs) +(Lr-,Lp)(Lp+O1-+Z+Fs) Lp-l-Or+Z+Fs p OrLp Lp(C1-+ Z+Fs)+(LrLp)(Lp+Cr+Z+F-s) (cleymng) C1'Lp LrLp+LrCr+LrZ+LrFs Lp P (clearing) =OTLP F XLt substituting ig F I -Lr Lp+Cr+Z+- -)L 1) r CrLpFr Lr[Fr(Lp+Cr+Z) +Fp(Fr-FZ )]FrL?p (clearmg) OrFpLr Fr[Lr(Fp+C'r+Z) +Lp(Lr-Lp)] LrFp (demng) Cr Cr+Z+F s+Ls J 7 got (substituting for F8 and Ls F rL 1(Cr Z) FpLr (Fr- Fp) LpFr(Lr Lp) as shown above and clearing) Total deflection=Ld+Fd-FCZ. The preceding values are approximately Relay instrument setting or setting of in-' what have been employed in controlling the 'sulated gap in relay=Ld+ F d Cd-i- Ce. temperature of a thirty-four foot spelter I As an example with approximate values bath containing ap roximately sixty tons of as foows substituted in the formulae an molten spelter an used in the commercial idea 0 relative effects can be obtained- Cr==180, z=30, Fp=11, Fr=91, L =12,

Lr=88, Ct=800, Ft= 1225, Lt= 825, Ce= 100.

Ld= 80 degrees Fahrenheit. F(l=1'20 degrees Fahrenheit. Cd= 625 degrees Fahrenheit. Ce=100 degrees Fahrenheit.

Total=d=insulated gap setting of relay 37 for obtaining temperature of 900 at G, (Ct+Ce=900).

. be obtained in changing fromone operating product-ion of galvanized wire. 7

By adjusting the various potentiometer coils, that is by adjusting the movable contacts alongthe coils so as to change their resistance values. in the several thermo-couple circuits, and by adjusting the insulated gap 43 in the relay instrument 37 almost any desired temperature may be controlled, and by shifting the position of the gap 43 alone, the desired temperature setting may temperature to another as it is only necessary to shift gap 43 in accordance with the.

desired change of temperature.

While I have described my invention as applied to the regulation of the temperature of a bath of molten spelter in a spelter pan, it will be understood that its use is in no wise limited thereto, but it may be used to regulate the temperature of many other forms of furnaces, fluid bodies and the like, wherever a constant temperature is desired.

It will be understood also, that while I have shown and described one specific em- I bodiment of my invention, that I do not located at the point to be regulated, and

other of said elements being located at spaced points relativel closer to said source of heat than said rst named element, said elements being adapted to supply varying independent electric currents 1n accordance with temperature changes, and means for interconnecting said currents so as to obtain a desired proportionate amount ofeach of said currents, and for accumulating said proportionate amounts of current into asingle current, and means operable by said single current for varying the heat supplied.

2. A temperature control mechanism C0111- prising the combination with a source of heat, of a plurality of temperature responsive elements, one of said elements being located at the point to be regulated, and other of said elements being located at spaced points from said first named element and adjacent the source of heat supplied and re-.

quired respectively, said elements being adapted to supply varying independent electric currents in accordance with temperature changes, and means for interconnecting said currents so as to obtain a desired proportionate amount of each of said cur rents, and for accumulating said proportionate amounts of current into a single current, and means operable by said single current for varying the heat supplied.

3. A temperature control mechanism comprising the combination with a source of heat, of a plurality of temperature responsive elements, one of said elements. being located at the point to be regulated, a second element spaced from said first element and adjacent the source of heat supplied, and a third element spaced from said first element and adjacent the point at which, heat is required, said elements being adapted to supply varying independent electric currents in accordance with temperature changes,

and means for interconnecting said currents so as to obtain a desired proportionate amount of each of said currents, and for accumulating said proportionate amounts of current into a single current, and means 0perable by said single current for varying the heat supplied.

4. An electrical paratus comprising the combination with a receptacle for containing material to be heated, and a source of heat for heating said material, of a temperature responsive element located in the material to be heated at approximately the point at which the temperature of the material is to be controlled, a second temperature responsive element located in the material closely relative to the source of heat, and a third heat responsive element located in the path of the heat from said source of heat so as to respond to the varying quantities of heat evolved from said-source of heat, sald temperature responsive elements being adapted to supply varying independent electric currents in accordance changes, and meansfor interconnecting said currents so as to obtain a desired proportemperature control ap- I with temperature tionate amount of each of said currents,

and for accumulating. said proportionate amounts of current into a single current, and means including a single galvanometer operable by saidsingle current for varying the heat supplied.

5. An electrical temperature control apparatus comprising the combination with a receptacle for containing material to be heated, and a source of heat for heating said material, of a thermo-couple located in the material to be heated at approximately the point at which the temperature of the material is to be controlled, a second thermocouple located in the material to be heated closely relative to the source of heat, anda third thermo-couple located in the path of the heat from said source of heat so as to respond to the varying quantities of heat evolved from said source of heat, said thermo-couples being adapted to supply varying independent electric currents 1n accordance with temperature changes, and means for interconnecting said currents so as to obtain a desired proportionate amount of each of said currents, and for accumulating said proportionate amounts of current into a single current, and means including a single galvanometer operable by said'single current for varying the heat supplied.

6. An electrical temperature control apparatus comprising the combination with a re ceptacle for containing material to be heated, and a source of heat for heating said material, of a thermo-couple located in the material to be heated at approximately the point at which the temperature of the material is to be controlled, :1 second thermo-couple located in the material to be heated closely relative to the source of heat, and a third thermo-couple located in the path of the heat from said source of heat so as to respond to the varying quantities of heatevolved from said source of heat, said thermo-couples being adapted to supply electric currents varying in quantity in proportion to the varying temperatures affecting the thermo-couples, a potentiometer unit having means for interconnecting and accumulating said currents from said thermo-couples, said means being adjustable. to obtain various proportionate amounts of at least some of said currents, and means operable by the accumulated current for varying the source of heat.

7. In a temperature control apparatus including a plurality of sources of electric current and means for varying the electric currents in proportion to temperature changes, of a potentiometer unit having means for interconnecting and accumulating said currents, said means being adjustable to accumulate various proportionate amounts of at least some of said currents.

8. In a temperature control apparatus including a plurality of thermo-couples affected by the temperatures to be controlled so as to provide electric currents varying in proportion to the temperature changes, of a potentiometer unit having means for interconnecting and accumulating said currents said means being adjustable to accumulate various proportionate amounts of at least some of said currents.

9. In a temperature control apparatus including a plurality of thermo-couples affected by-the temperatures to be controlled so as to provide electric currents varying in proportion to the temperature changes,of a

potentiometer unit having means for inter-,

of a temperature control system comprising a movable control, a plurality of thermocouples cooperating to determine the position of said control, one of said thermo-couples being located at a point at which a redetermined constant temperature is desired and representing a constant, and the other of said thermo-eouples being more closely ad- I jacent' the source of heat and in the path of the heat required and supplied res ectively, the sum of the efi'ectof said ast named thermo-couples representing a constant, and means operated by said control to regulate said source of heat to oppositely influence said last mentioned thermo-couples.

11. In a temperature control system, a

galvanometer, a plurality of thermo-couple circuits cooperating to determine the position of said galvanometer, one of said thermo-couple circuits representing a constant, and the sum of the other circuits representing a constant, and a fuel control operated by said galvanometer to oppositely influence said last mentioned circuits.

In testimony whereof, I have hereunto signed my name. 1

ALBERT BONDS.

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