US1924895A - Heat exchange system control - Google Patents

Description

Aug. 29, 1933. L. F. wHnNEY 1,924, 95

HEAT EXCHANGE SYSTEM CONTROL Filed Jan. 30, 1931 2 Sheets-Sheet l Inventor Lyman 1? Whitney. 777 Att yS.

Aug. 29, 1933. F WHITNEY 1,924,895

H EAT EXCHANGE SYSTEM CONTROL Filed Jan. 30, 1931 2 Sheets-Sheet 2.

66 I f 37/ 74 Aj? 6/ 58 A a 74 w 5/ I 5.5

W 70 Inventor Att ys.

Patented Aug. 29, 1933 UNITED STATES HEAT. EXCHANGE SYSTEM CONTROL 11 Claim.

This invention relates to a control arrangement for boilers and/or heat exchange systems such as refrigerating systems and in one aspect relates to means arranged to impede or stop the heating of a boiler! when an insumcient amount of liquid is supplied tothe same or the liquid in the boiler is depleted for any reason.

This invention affords a safety arrangement for a refrigerating system which employs a boiler and which may include means for maintaining a low subatmospheric pressure in the system. In accordance with the present invention, the system may be so arranged that an increase in the internal pressure thereof, due, for example, to the leakage of air into the system or to the failure of the purger to operate. will be effective in causing the; depletion of the liquid in the boiler and consequent interruption to the supply of heat to the boiler, while the heating of the' boiler will also be interrupted should the liquid level therein become unduly low for any other reason. The present invention provides an arrangement which is particularly adapted to employment in systems having a pipe or duct connected to the boiler and normally containing liquid as, for example, liquid that is being fed to the boiler. Thus the invention may be employed in refrigerating systems having vaporizers or boilers, the liquid in which is being replenished by means of a duct which may contain a column of the fluid to be vaporized. For example, this invention is particularly advantageous when employed with a refrigerating system of the character disclosed in the Patent No. 1,761,551 to Eastman A. Weaver dated June 3, 1930 and the copending applica tion of Daniel F. Comstock, No. 198,715, filed June 11,192! as well as my copending application, Serial No. 503,006 filed December 1'7,- 1930. The above identified patent and applications disclose refrigerating apparatus which includes a boiler or vaporizer for the propellent fluid, which preferably may be mercury, and the vapor-of which is supplied to the aspirator nozzle for entrainment of refrigerant vapor from a cooler, the propellant being condensed after the entrainment of the refrigerant and a pressure balancing column to the boiler.

In accordance with the present invention,ya suitable control factor may be provided to interrupt the application of heat to the boiler when the liquid level in the latter becomes inordinately low. Such a control factor preferably is associated with the duct which feeds liquid to the boiler, and it may include a thermostatic element which is actuated when the liquid contained returned through 7 Application January 30, 1931. Serial N0. 512,405

within the duct is displaced ordinarily has a much higher PATENT oar-ice by the vapor, which temperature than the liquid in this part of the system,

and has a much greater heat supplying power. 1

Thus, in the case of a boiler gas burner,

pro ded with a a thermostatic control member may normally serve to retain'a valve in the fuel sup-. ply line in-its open position, whilg an increase in the temperature of the may be eifective thus interrupting the flow of in causing the valve to close, fuel to the burner.

A further aspect of the invention relates to the arrangement of a low pressure system such as a refrigerating system which is provided with thermostatic member means that interrupt the normal flow of liquid to the boiler should the pressurewithin the system rise due to the leakage of atmospheric air or for any other reason. The systemthat such an increase in pressure in the boiler, where.-

lowering of the liquid level is arranged so will result in upon the control device operates to interrupt the supply 'of heat to the boiler and operatioribfthe system.

- In the accompanying drawings:

Fig. 1 is a schematic view of are! thus stop future system to which my safety controlarrangement is applied;

Fig. 2 is an enlarged horizontal section through, and the associated liquid the control member duct;

Fig. 3 is Fig. 2;

Fig. 4 is a top view of the control means, ing the fluid pipe in section; and

Fig. 5 is an elevational view static element.

Fig. 1 illustrates typical app a section indicated by line 3--3 of show-' of the thermoaratus to which my control system may be applied, such as a refrigerating system employing a heavy propellant of comparatively high boiling point, for example mercury, and a fri'gerant such as water: same general character as identified patent-of Eastman A.

This .system may be provided with a 2 into one suitable flue 4 may be having a central firebox a burner 3 projects. A

lighter, .more volatile re this system bein of the disclosed in the above- Weaver. a

boiler 1 end 'of which rigerating provided to permit exhaustion of gases from the duct 6 firebox, and a fuel supply may lie-connected to the burner 3, being arranged-to receive fuel from "any suitable source such mains.

as the city gas A vapor duct '7 extends upwardly from the boiler 1 to an aspirator nozzle into an entraining chamber 9.

8 whichmroiects A vapor duct 10 connects chamber 9' with the upper part of a cooler 12 which contains a liquid body of refrigerant such as water. Propellent vapor passing from the nozzle 8 at high speed is effective in entraining vapor from the cooler 12 and in causing rapid evaporation at the surface of the contained liquid thereby causing the cooler to have a low temperature. The mixture of propellant and refrigerant vapors passes into the compression and condensing funnel 15 which is aligned with the asplrator nozzle and which is provided with suitable cooling means such' as fins 16, so that the high boiling point propellant may be condensed out of the vapor mixture. The funnel 15 is inclined and propellant condensed therein flows downwardly to a downwardly extending propellant drain 17.

An upwardly extending vapor duct 19 is joined to the intermediate part of a separating chamber 20, the upper portion of which is connected to a refrigerant condenser 21. The vapor received by the condenser 21' is liquefied and flows back to the chamber 20, passing out of the lower part of the same into the duct 22 which forms one leg of a trap 23 that may contain mercury. The opposite leg of this trap is connected by a duct 25 with the cooler 12. The condensed'refrigerant forms a liquid column in duct 22, which reaches a suflicient height to balance the mercury column in the opposite leg of the trap 23, so that the refrigerant from the bottom of the column passes through the trap into duct 25 and thus returns to the cooler 12.

Preferably a system of this character may operate at subatmospheric pressure, and may be provided with means to interrupt the return of propellant to the boiler when the internal pressure of the system rises unduly, as for example, due to leakage of atmospheric air into the system. The system preferably may be provided with a purger or evacuating means automatically operable to exhaust gases fromthe system to aid in maintaining a low internal pressure and to compensate-for any slight leakage that may occur. For this purpose a duct 30 is connected to the. upper part of the condenser 21 and is arranged to receive non-condensable gases. The propellant from the drain 1'? flows through a trap 31 that is connected to an entraining chamber 33, the upper part of which communicates with the duct 30. A downwardly extending tube 34 of restricted diameter is connected to the lower part of chamber 32 and is so dimensioned that globules of the propellant will pass downwardly through the same, acting as separate liquid pistons between which bodies of non-condensable gas may be entrained. The lower end of tube 34 isconne'cted to a receptacle or standpipe 35 having an enlarged upper portion or reservoir 36 which is open to the air. A propellant receiving duct 39 is connected to the lower part of the standpipe and extends upwardly to the downwardly inclined duct 40,.the juncture of ducts 39 and 40 providing a spill-over which determines the pressure at the lower end of the tube 34 and the standpipe 35. The duct 40 is joined to a main propellant return pipe 32, the lower end of which is connected to the lower part of boiler 1. The return pipe 32 is provided with an upwardly extending continuation 29 that forms a drain to receive propellant particles which may condense in the mixing chamber 9.

A mercury containing trap 27 may be connected to the bottom of the cooler 12 to receive stray propellant particles therefrom, this trap densed out of the mixture in the funnel or con-- denser section 15 and the refrigerant vapor passing upwardly to the refrigerant condenser 21; the condensed refrigerant from the latter passes through the pressure balancing trap 23. and thus returns to the cooler 12.

The major portion of the condensed propellant is received by the drain 17 and thus passes through trap 31 to the chamber 32 and the tube 34. Non-condensable gases which occur in the system are received from the pipe 30 and entrained between propellant globules that pass downwardly through tube 34. The standpipe 35 normally contains a column of mercury which has its upper surface exposed to atmospheric pressure; accordingly, the non-condensable gases =bubble upwardly through this mercury column and are exhausted to the atmosphere. The merity, refrigerant vapor may be entrained in the pipe 34 and rise to' the top of the mercury column in standpipe 35, thus being emitted from the system. However, the amount of vapor which is thus exhausted even over a long period of time is substantially negligible. Should the pressure within the system rise due to'the leakage of gases or atmospheric air into the system at a greater rate than it may be exhausted by the purger, the internal pressure will cause the mercury level in standpipe .35 to rise against atmospheric pressure so that the mercury may flow upwardly into the reservoir 36. The capacity of this part of the system is so determined that an increase in the internal pressure of the system to' a predetermined point will result in the collection of so much mercury in the standpipe and the reservoir that continued flow of mercury upwardly through duct 39 to duct 40 will be interrupted and the supply of propellant in the boiler will quickly become depleted so that vapor may pass upwardly.

into duct 32.

It will be understood that a system of the character just disclosed has been described as representing a typical arrangement to which my safety control means is particularly applicable, but that this control means may be applied to many other types of systems, for example, to a system such as shown in my copending application Serial No. 503,006 which is provided with a propellant lifter to permit the top of the pressure balancing column of mercury which re'--- turns propellant to the boiler to be at a level above the propellant condenser.

In accordance with the present invention, control means may be associated with a duct which contains-liquid and is connected to the vaporizer below the normal liquid level therein, the control the connection 51 ment with the casing and to tion 59 o! the valve member may be means'being arranged to be responsive to an elevation in the temperature of the fluid within the duct, so that whenever the fluid is displaced of heat to the boiler in whatever manner that supply may be effected; thus with a boiler having a burner for a combustible mixture, such as a 'mixture of illuminating gas and air, the control means may include a valve to interrupt the flow of at least one of the ingredients of combustion to the burner. This control means includes a part to interrupt-the flow of fuel or energy to the heating iactor 3 of the boiler and accordingly may be associated with the fuel supply duct 6. As shown in Fig. 2, the latter may be connected to a casing 50 which is disposed in heat transfer relation to the duct 32, and preferably is located adjoining flue .4. Figs. 2, 3 and 4 illustrate this arrangement in greater detail, it being evident that the casing 50 is provided with an outlet portion or connection 51 which is ioinedto the section of duct 6 that extends to the burner and also is provided with the inlet connection 52 that is connected to the section of duct 6 that is connected to the gas mains or other source or fuel supply.

The casing 50 is provided with a substantially cylindrical recess which has an open end opposite and which is provided with internal threads 54 to receive external threads upon acylindrical member 55. The latter may be provided with an external head 56 to facilitate its movement into and out of threaded engageprovide a shoulder for engagement with an annular face of the casing. V

Member 56 is provided with a cylinder internal recess 5'7 which receives a slidable valve member 58, the latter having a substantially cylindrical body portion 59 with a centralrecess 60 that receives a compression spring 61. The latter has one end normally in engagement with valve 58 and its opposite end in engagement with the head 56 of member 55 so that it tends to urge the valve toward the connection 51.

The mouth of a passage which extends to onnection 51 is provided with a beveled surface 66 1.0 iorm'a valve seat that cooperates with a tapered extension 69 upon the end of member 58. Thus when the spring 61 is free to operate, the member 69 engages the valve seat 66 and flow or fuel from the inlet 52 through the casing 50 to the outlet 51 is prevented.

During normal operationof the system, however, I prefer to provide means locking the valve in open position. Such means comprises a segmental member '70 of thermostatic metal which is illustrated more particularly in Figs. 3 and 5,

this thermostatic member having an end portion secured by a fastening element '71 in a groove '72 in the cylindrical member 55. The body porcut away to clear the end of element '71 (Fig. 3) A continuation of the groove '72 provides a slot '73 which permits the thermostatic member to engage a segmental groove 74 in valve 58, thereby locking the latter in its open pos'tion and holding the spring 61 under compression. The member'70 is arranged,-,however, so that in response to a suitable increase in its temperature, it will spring out of engagement with the groove '74, thus releasing the valve member 58, so that the spring is efiective in engaging valve surface 69 with the seat 66, thereby interrupting the fuel flow.

A plate having a semi-cylindrical recess is secured by screws 82 to a portion ofthe casing. 50 which has a complementarily formed recess, 80 these recesses cooperating to provide a substantially cylindrical opening through which the duct 32 extends, the plate and screws being efiective in clamping the duct in good heat transfer relation to casing 50. 85 7 During normal operation of the system the duct portion 32 adjoining casing50 contains liq- Y uid propellant and the valve will be held in its open position. When -the liquid in the boiler 1 is depleted for any reason, as, for example, due

to the clogging of the aspirator nozzle 8, the vapor will displace the liquid 'mercury in the lower part of the duct 32 and vapor will pass to the region of the casing 50. Obviously this propellant vapor has atemperature which is distinctly higher than that of the liquid normally contained in the duct 32, and can rapidly conduct heat to the casing 50 so that the thermo-'- static element '70 expands gagement with the groove ber 58, permitting the and moves out of en- 74 in the valve memlatter to be moved'to its closedposition by spring 61. It is evident that in case of an 'undue increase in the internal pressure of the system, for example due to rapid leakage of atmospheric air into the system, the mercury will rise into the reservoir 36 and will no longer be supplied to the duct 32 through the duct 40. The downwardly flowing propellant received by duct 32 from duct 40 normally aids the cooling of the pipe 32 and casing 50, thus tending to offset the heating eilect oi the juxtaposed 'flue, but as soon as this flow is interrupted, for

example, due to the collection of propellant in receptacle 36 the heat from the flue is efiective in causing a rapid increase in the temperatureof the casing 50 and the heat-responsive element '70. Thus the heat from iiue 4 not only causes the more rapid operation of the shut-ofi device, in response to abnormal operating conditions; but under certain conditions, this heat may be eflective in causing operation of the device, be-' fore the liquid propellant passes out of the lower end or duct 32. c Accordingly further supply of fuel to the boiler is prevented and theoperation of the system is interrupted. In order to permi the system to resume operation, it is necessary to remove-the members 55 and 58 from the casing 50, reassembling them in their normal position with the spring 61 compressed so that the cooled and contracted thermostatic element 70 may again engage the groove '74. This arrangement is efiective in calling attention to the condition which has caused the development of the high pressure in the vaporizer and an indication is thus afiorded of the ad'visability of expert attention to the system.

From the foregoing, it will be evident that I have provided safety control means to interrupt the supply of heat to the boiler which is connected to a duct that normally contains liquid, but which will contain vapor whenever the boiler pressure becomes inordinately high or whenever the liquid level becomes undesirably low in the boiler. Accordingly, this arrangement is efiective in interrupting the operation of the system when the flow of propellant to the boiler is interrupted-or undulyimpeded as for example due to the leakage of atmospheric air into the system and the collection of mercury in reservoir 36. Furthera more, should the aspirator nozzle 8 become 15 clogged the pressure in the boiler will become sufficiently high to displace the mercury and to cause vapor to flow upwardly into the duct 32 thus causing operation of the shut-off means. If a leak should develop in the boiler so that the level of the mercury should become unduly low, a similar result will take place. An arrangement of this character is particularly advantageous with a system having a propellant lifter such as that disclosed in my copending application, Serial No. 503,006 which is included by reference herein. Should such a propellent lifter fail to operate for any reason and thus terminate the return of propellant to the boiler, the shut-off means will operate in the same manner to protect the system against injury and to prevent burning of the boiler. It is thus evident that I have provided means to interrupt operation of the system under practically any condition which would make continued operation dangerous or undesirable.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. Apparatus of the class described comprising a boiler, a burner associated therewith, a passage supplying fluid to the burner, a vapor outlet pipe connected to the boiler, a duct normally containing liquid connected to the boiler, a heat distortable thermostat in heat transfer relation to a portion of the duct remote from the boiler, said duct being arranged so that depletion of liquid in the boiler will cause hot vapor to pass into the duct and effect movement of the thermostat, a shut-off valve in the fluid passage, a spring urging the valve toward its closed position, the thermostat normally locking the valve in open position and when actuated by heat releasing the valve so that it is closed by the spring, thus interrupting the flow of fluid to the burner.

2. Apparatus of the class described, comprising a boiler, a burner associated therewith, a fuel supply pipe leading to the boiler, a liquid supply duct connected to the boiler and normally containing a column of liquid to balance boiler pressure and to supply liquid to the boiler, a valve casing in heat transfer relation to a portion of said duct and connected to the pipe, a movable valve member in said casing arranged when in engagement with a seat in the casing to interrupt fuel flow through the pipe, a spring in the casing urging the valve toward the seat, a thermostat normally engaging a' recess in the valve member to hold it away from the seat, said thermostat being movable out of said recess to release the valve in response to a high temperature.

3. Apparatus of the class described comprising a boiler, a vapor outlet pipe connected to the upper part of the boiler, an aspirator .nozzle connected to said pipe, a duct connected to the lower part of the boiler and normally containing a-displaceable liquid column, said duct having an upper portion disposed above the boiler and normally free from liquid, means for supplying heat to the boiler, a shut-oil to terminate the supply of heat to the boiler, a thermostat 0 rable under the influence of heat to cause the s ut-ofi to interrupt the supply of heat,,said

thermostat being disposed adjoining the duct, whereby clogging of the nozzle and consequent high vapor pressure in the boiler causes vapor from the boiler to displace the liquid column in the duct, so that the thermostat will causethe shut-off to operate.

4. Apparatus of the class described comprising a fluid circuit including a boiler, a vapor outlet pipe connected to the upper part of the boiler, a supply duct connected to the lower part of the boiler and normally containing a displaceable liquid column, means for supplying heat to the boiler, a shut-off to terminate the supply of heat, a heat-responsive element operable'under the influence of heat to cause the shut-off. to interrupt the supply of heat, said heat-responsive element being disposed adjoining the supply duct, and means operable in response to a pressure change in the circuit to interrupt flow of liquid into the supply duct and thence to the boiler, whereby vapor will flow to the region of the thermostat and cause operation of the shut-off.

5. Apparatus of the class described comprising a fluid circuit having a low pressure portion normally operating at subatmospheric pressure and including a boiler, a vapor outlet pipe connected to the upper part of the boiler, a supply duct connected to the lower part of the boiler and normally containing a displaceable liquid column, means for supplying heat to the boiler, a shutolf to terminate the supply of heat, a thermostat .operable under the influence of heat to cause the shut-off to interrupt the supply of heat, said thermostat being disposed adjoining the supply duct, and means operable in response to an increase in the pressure of said low pressure portion of the circuit to interrupt flow of liquid into the supply duct and thence to the boiler, whereby vapor will flow to the region of the thermostat and cause operation of the shutoflf.

6. Apparatus of the class described comprising a fluid circuit having a low pressure portion normally operating at subatmospheric pressure and including 'a boiler, a vapor outlet pipe connected to the upper part of the boiler, a supply duct connected to the lower part of the boiler and normally containing a displaceable liquid column, means for supplying heat to the boiler,

a shut-off to terminate the supply of heat, a thermostat operable under the influence of heat to cause the shut-off to interrupt the supply of heat, said thermostat being disposed adjoining t supply duct, a duct connected to said circ and normally containing a liquid column with its upper surface subject to atmospheric pressure, whereby increase of the internal pressure will cause the height of said column to increase, thus depleting the remainder of the system of liquid sufliciently to interrupt the return of liquid to the boiler, whereby vapor will flow to the region of the thermostat and cause operation ,of the shut-off.

7. Apparatus of the class described comprising a fluid circuit including a boiler, a heater associated therewith, a supply duct connected to the boiler, a vapor duct connected to the boiler, and

a receptacle associated with the supply duct and communicating with the atmosphere, said receptacle containing a liquid column with its upper surface exposed to atmospheric pressure and arranged so that the height of said column may vary in response to the ratio between internal pressure of the system and atmospheric pressure, the receptacle having a suflicient capacity toprevent furtherflow of liquid through the supply duct to the boiler when the pressure ratio reaches a predetermined'point, and control means operable to interrupt operation of the heater when the flow of liquid to the boiler is thus interruped.

8. Apparatus of the class described comprising a fluid circuit including a boiler, a heater associated therewith, a supply duct connected to the boiler, a vapor duct connected to the boiler, and

- a receptacle associated with the supply duct and a predetermined portion of the receptacle tostop operation of the heater.

9. Apparatus of the class described comprising a fluid circuit having a low pressure portion normally operating at subatmospheric pressure, means for causing fluid circulation in said circuit, and means associated with said first means to interrupt the circulation of fluid in response to an undue rise in the pressure of said low pressure portion of the circuit.

10. Apparatus of the class described comprising a fluid circuit having a low pressure portion normally operating at subatmospheric pressure,

means for causing fluid circulation in said circuit,

purging means operable to exhaust non-condensable gases from the system, and means associated with said first means and the purging means to interrupt the circulation of fluid in response to an undue rise in the pressure of said low pressure portion of the circuit.

11. Apparatus of the class described, comprising a boiler, a combustion chamber associated therewith, a flue connected to said chamber, a vapor outlet duct connected to the upper part of the boiler, a liquid supply duct connected to the boiler below said outlet duct, a fuel line supplying a combustible fluid to the combustion chamber, shut-01f means associated with said line and operable to impede the flow of fuel, a heat-responsive. element normally restraining the shut-off device from operating, said element being in heat transfer relation to said flue and liquid supply duct, heat from the flue being efl'ective in causing the heat-responsive element to release the shutoiT means, thus impeding fuel flow, when the flow of liquid through the supply duct is interrupted.

LYMAN F. WHITNEY.

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