US2349396A - Refrigeration - Google Patents

Description

May 23, 1944. s. w. E. ANDERSSON REFRIGERATION Filed'Aug. 21, 1941 2 Sheets-Sheet 1 INVENTOR ATTORNEY M y 1 s. w. E. ANDERSSON REFRIGERATION Filed Aug. 21, 1941 2 Sheets-Sheet 2 IZ IEI TOR M 2 @ATTORNEY Patented May 23, 1944 2,349,396 nnraronns'rron Sven W. E. Andersson, Evansville, Ind., assignor to Servel, Inc., New York, N. Y., a corporation of Delaware Application August 2 1, 1941, Serial No. 407,745 11 Claims. (Cl. 62-5) This invention relates to' refrigeration, and more particularly to refrigeration apparatus of the kind operated by heat. l

In absorption refrigeration apparatus of the kind described in application Serial No. 350,239 of Albert R. Thomas, a generator or heat receiving part isprovided with a jacket forming a.

chamber which is vented to atmosphere and within which are disposed a plurality of vertical tubes or risers. Steam is supplied from a boiler to thechamber so that substantially full length heating of the tubes may be effected, whereby absorption liquid therein is heated to cause expuision of refrigerant vapor and also eflect liftingor raising of liquid to a higher level by gas or vapor-lift action.

Fig. 3 is a vertical sectional view taken on line 3-4 of Fi 2; and v Fig. 4 is a horizontal sectional view taken at line 4-4 ofFig. 2.

Referring to Fig. 1, the invention is shown in connection with refrigeration apparatus of an absorption type like that described in the aforementioned Thomas application. A system of this type operates at low pressures and includes a generator I 0, a condenser ll, an evaporator l2, and an absorber l4 which are interconnected in such a manner that the pressure differentia1 in the apparatus is maintained by liquid columns.

The generator It) includes an outer shell l5 within which are disposed a plurality of vertical riser tubes l6 having the lower ends thereof com- The steam supplied to the generator chamber In many instances, because of boiler so that provision must be made for returning liquid condensate to the boiler.

It is an object of the invention to provide an improved condensate retinn pump which is extremely quiet in operation to lift or raise condensate formed in the generator so that the raised condensate can flow to the boiler.

Another object of the invention is to provide an improvement for utilizing warm condensate'to shut on? the heat supply to the steam boiler in the event the condensate return pump is rendered inoperative to .retumcondensate from the generator to the steam boiler.

Arurther object of the invention is to provide an improvement for returning condensate to the boiler in such a manner that a single expansible fluid thermostat can be utilized to shut ed the heat supply to the steam boiler with rise of temperature occasionedeither by passing or steam through the vent in'the generator chamber or operating failure of the condensate return pump.

The invention, .together with the above and other objects and advantages thereof, will be better understood fromthe following description taken in conjunction with the accompanying drawings forming a part oi this specification, and

of which:

Fig. 1 illustrates more or less diagrammatically refrigeration apparatus and a heating system therefor provided with a condensate return 'pump embodying the invention;

Fig. 2 is a view in elevation, partly broken away. illustrating more clearly. the condensate return pump shown in Fig. 1;

municating with a space I! arid the upper ends thereof extending into and above the bottom of a vessel l8. The space I 9 within shell l5 and about the tubes It forms a steam chamber to which steam is supplied through a conduit from a steam boiler 2|.

The boiler 2| is provided with fire or heating tube 22 into the lower end of which is adapted to project the' flame produced by a burner 23. A combustible gas is delivered from a source of supply through a conduit 24 in which is connected an electro-magnetically operated solenoid valve 25 connected by conductors 26 and 21 to a suit- 30 able source of electrical energy. While only a single heating tube and burner are illustrated a number of heating tubes and burners may be employed with the upper end of each tube connected to a flue or riser 28. The water in boiler 2| is heated by the hot gases passing through the heating tubes 22, thereby producing steam which flows through conduit 20 to generator Ill.

The space l9 provides for full length heating of riser tubes I6 wi a vent 30 provided at the 40 upper end of shell l5 through which steam can flow into the atmosphere. Condensate formed in steam chamber i9 is returned to boiler 2| through a conduit 3|, a condensate return pump 32 to be described presently, and a conduit 33.

The heating of riser tubes IS in generator l0 by the steam causes'refrigerant vapor to be ex- I pelled from absorbent, such expelled vapor beof evaporator II. The refrigerant evaporates in I flows therefrom to an absorber M in which the vapor is absorbed into a liquid absorbent, such as lithium chloride solution, for example, which enters the upper part of the absorber through a conduit 31. The absorption liquid enriched in refrigerant is conducted from absorber l4 through conduit 38, a, firstpassage in liquid heat exchanger 39, conduit 40, vessel 4|, and conduit 42 into space ll of generator l6. Refrigerant vapor is expelled out of solution in generator l by heating, and the solution is raised by gas or vapor lift action in riser tubes I6, as explained above.

The absorption liquid in vessel I8 is deprived of refrigerant since refrigerant vapor has been expelled therefrom in generator H], The absorption liquid in vessel 8 flows therefrom through conduit 43, a second passage in liquid heat exchanger 33 and conduit 31 into the upper part of absorber I4. This circulation of absorption liquid results from the raising of liquid in riser tubes I6, whereby the liquid can flow to absorber l4 and return from the latter to generator ID by force of gravity.

The upper part of vessel 4| and vessel 8 are connected by a conduit 48, so that the pressure in the vessel is equalized with the pressure in the upper part of generator I0 and condenser The absorber l4 and condenser constitute heat rejecting parts of the refrigeration apparatus and are cooled by a suitable cooling medium, such as water, for example, which is conducted from a suitabl source of supply through a conduit 44 to a bank of tubes 45 within the absorber whereby heat of absorption is given up to the cooling water. The cooling water is conducted from absorber |4 through a conduit 46 to condenser in Which heat of condensation is given up to the cooling water, the cooling water thence leaving the condenser through a conduit 41.

In order to simplify the drawings the parts of the refrigeration. apparatus have not been shown in detail, such an illustration of the parts not being necessary for an understanding of this invention. The disclosure in the aforementioned Thomas application may be considered as being incorporated in this application and, if desired, reference may be made thereto for a detailed description of the refrigeration apparatus.

In order to keep the overall height of the refrigeration apparatus and heating system to a minimum, the bottom part of the generator I0 is below the surface level of water maintained in boiler 2|. Under these conditions provision must be made for lifting or raising condensate formed in generator l0, so that the raised condensate can flow to the boiler.

In accordance with this invention, therefore, a condensate return pump 32 is connected in the condensate return line including conduits 3| and 33. The pump 32 comprises an outer shell 50 having a bottom 5| and a top 52. Integrally with the top 52 are formed a downwardly depending sleeve 53 and reinforcing ribs 54 therefor. The lower end of sleeve 53 is enlarged at 55 to form a recess adapted to receive a rotatable impeller 56. The impeller 56 is multi-bladed, as shown most clearly in Figs. 3 and 4, and is securedto the lower end of a shaft 51 which extends upwardly through sleeve 53. The shaft 51 is carried by a rotor of an electric motor 58 in which the rotor is joumaled in any suitable manner. The electric motor 58 is secured to the top 52 and provided with a connection 59 for connecting the motor to a source of electrical energy.

To the enlarged part 55 at the lower end of sleeve 53 is secured a plate 60 to form a chamber 6| in which the impeller 56 is adapted to rotate. The plate 6|! is formed with a central opening 62 about which is formed a depending flange or lip 63. At the outer peripheral edge of plate 60 is formed an annular skirt or flange 64 of greater depth than lip 63 and to which is secured a suitable screen 65 to prevent foreign matter from entering the pump chamber 6|.

During operation of the pump 32 the warm condensate flows by gravity from the bottom part of generator chamber 9 through conduit (into the bottom part of shell 56, The condensate passes through the opening 62 in plate 60 into chamber 6| in which the velocity of the liquid is increased by the impeller 56, the velocity being converted into pressure by the chamber to cause raising or lifting of liquid through a riser tube 66 which is connected at its lower end to the outer peripheral part of chamber 6|. The riser tube 66 is located within shell 50 with the upper end thereof terminating in a flanged opening 61 formed in the top 52. The flanged opening 67 is threaded to receive one end of conduit 33 through which th raised condensate flows to boiler 2|.

The condensate return pump 32 is especially quiet in operation due to the provision of lip 63 which extends downwardly from the inlet opening 62 of chamber 6| into the pocket formed by the skirt or flange 64. With the pump operating to lift condensate through tube 66, the lip 63 serves to confine thenoise produced by the pump that otherwise would be quite noticeable.

In the event the condensate return pump 32 fails to operate, it is desirable to shut off the heat supply to the boiler 2|. This is accomplished by providing pump 32 with an overflow tube 68 into the upper part of which condensate can overflow from shell 50 through a connection 69. To the bottom part of tube 68 is connected an overflow tube 10 through which condensate flows to waste.

In t e b t m pa t of tube 68 is disposed a bulb H of an expansible fluid thermostat. The expansible fluid thermostat is charged with a suitable volatile fluid and includes the bulb 1|, an expansible and contractible bellows l2 arranged in a casing 13, and a capillary tube 14 connecting the bulb H and bellows I2. The bellows I2 is arranged to operate a suitable switch 15 Which is mounted in casing I3 and connected in conductor 26. The expansible fluid thermo stat and switch 16 associated therewith are fully described in my application Serial No. 407,746 filed August 21, 1941, and have not been shown in detail in the drawings since a complete illusstration of these parts is not necessary for an understanding of the present invention. When reference is made to my co-pending application it will readily be understood that switch 15 is of the manual reset type and, when closed, completes an electrical circuit for solenoid valve 25 to energize and open the latter so that gas can flow through conduit 24 to burner 23.

In the event pump 32 fails to operate, the liquid level rises in shell '50 until condensate overare also connected in the circuit of the solenoid flows through connection 69 into tube 68. The

warm condensate flowing over the surface of bulb ll heats the latter to cause the pressure of the volatile fluid in the expansible' fluid thermostat to increase. When the pressure in the expansible fluid thermostat increases due to heating of bulb 1 I, the expansible bellows 12 expands sufliciently to cause switch 15 to open and break the circuit for solenoid valve 25, whereby the latter closes to shut off flow of gas to burner 23 and hence shut ad the heat supply to the burner.

It is also desirable to shut oil the heat supply to burner 2| in the event steam flowsfrom generator chamber l9 through vent 30 into the atmosphere. This may occur, for example, when circulation of air past cooling element I2 is riot eflected and there is los of load on the latter. In order that a single expansible fluid thermostat can be employed to shut off the heat supply either when steam flows through vent 30 or pump 32 fails to return condensate from generator chamber l9 to. boiler 2|, a' second thermal bulb I6 is connected in capillary tube 14. The bulb I6 is located in vent 30 and becomes heated when steam flows through the vent into the atmos: phere; With heating of bulb 16 the pressure of the volatile fluid in the expansible fluid thermostat increases to cause opening of switch 15, in the manner explained above when bulb "H becomes heated.

' Since the generator chamber I9 is vented to atmosphere, the heating system operates substantially at atmospheric pressure with the steam being at a temperature of approximately 212 F. when it flows through vent 30. The temperature of the warm condensate, on the other hand, may be approximately 160 F. when it overflows into tube 68 in the event pump 32 fails to operate. -In order to make certain that switch 15 will not open inadvertently on occasions when there is slight breathing in vent 30, that is, a slight amount of steam passing through the vent to atmosphere alternating with a slight amount of air flowinginto generator chamber l9, it is desirable to provide an expansible fluid thermostat which will be effective to open switch 15 when the temperature is relatively high and in the neighborhood of 160 I". Since this is a relatively high temperature at which to rate switch with the warm condensate, the parts have been arranged in such a manner that eflicient heat transfer from the condensate to bulb ll is obtained in the event pump 32 fails to operate. For this reason the bulb II is arranged below the connection 69 so that the condensate flows over the entire exterior surface of the bulb to obtain efllcient heat transfer. This arrangement is also advantageous in that the warmest condensate is employed at the instant that overflow occurs.

By providing the raised overflow tube Ill and causing warm condensate to flow over the surfaces of tube 68, the cold metal of the tube is heated very rapidly.

In addition to the control described, a normal control is usually provided for controlling the fuel supply to the burner 23 or a plurality of such burners, so that the rate at which steam is supplied to generator steam chamber l9 can be controlled. The normal control is generally operative responsive to a temperature condition affected by the cooling element and may be of the character described in my application Serial No. 406.177 flled August 14, 1941, in which sequential control of a plurality of burners is eifected.

valve 26 so that, when an adverse operating condition occurs which causes flow of steam through the vent 30 or overflow of warm condensate into tube 68, the control described above will open the circuit of the solenoid valve to shut off flow of fuel to the burner or burners. When the adverse operating condition is corrected and steam no longer flows through the vent 30 or warm condensate does not overflow into tube 68, the switch 15 can be manually closed to complete the circuit for the solenoid valve 25 so that the abovedescribed normal control of the burner 23 may be resumed to control the rate at which heat is sup plied to boiler 2 l In view of the foregoing, it will now be understood that an improved condensate return pump 32 has been provided which is extremely quiet in operation. Moreover, the parts of the pump are so located and arranged with respect to each other that the warm condensate can be efiectively utilized to shut off the heat supply to the steam boiler 2| in the event that the pump fails to operate.

Although a single embodiment of the invention has been shown and described, it will be apparent that modifications and changes can readily be made without departing from the spirit and scope of the invention, as pointed out in the fol; lowing claims.

What is claimed is:

1. In refrigeration apparatus, steam boiler, a heater for supplying heat to said boiler, a conduit to conduct steam from said boiler to said generator to efiect heating of the latter, a pump for raising to a higher level condensate formed at saidgenerator, a conduit for conducting the raised condensate to said boiler, and a control for controlling said heater to reduce the heat supplied by said heater to said boiler when said pump becomes ineffective to raise condensate to said higher level at a sufliciently rapid rate.

2. In refrigeration apparatus, a generator, a steam boiler, a heater for said boiler, a conduit to conduct steam from said boiler to said generator to effect heating of the latter, a pum for raising to a higher level condensate formed at said generator, a conduit for conducting the raised condensate to said boiler, anda control responsive to warm condensate formed at said generator for controlling said heater.

3. In refrigeration apparatus, a generator provided with a steam chamber having a condensate drain connection and a vent to atmosphere, a steam boiler, a conduit to conduct steam from said boiler to said generator to effect heatin of the latter, a pump including a movable element for raising to a higher level condensate formed in said chamber, and a conduit for conducting the raised condensate to said boiler, said vent and condensate drain connection being so constructed and arranged that, even when a liquid seal is formed in said drain connection by condensate passing therein from said chamber, excess steam The normal control may include switches which 7| said generator, a conduit for conducting the raised a generator, a

condensate to said boiler, a well into which warm condensate overflows when said pump fails to operate, and a thermostat control including a part located in said well and arranged to be heated by overflow condensate for controlling said ceiving part to effect heating of the latter, a

pump for raising to a higher level condensate formed at said heat receiving part, a conduit for conducting the raised condensate to said boiler, and a control including a portion arranged to be heated by condensate formed at said heat receiving part for controlling said electrically-operated valve.

6. In refrigeration apparatus, a heat receiving part, a source of steam, a conduit to conduct steam from said source to said heat receiving part to efiect heating of the latter, structure for controlling flow of steam from said source to said heat receiving part, a pump for raising to a higher level condensate formed at said heat receiving part, and a control for said structure operable when said pump becomes inefiective to raise condensate to the higher level at a sufficiently rapid rate.

7. In refrigeration apparatus, a heat receiving part, a source of steam, a, conduit to conduct steam from said source to said heat receiving part, and a pumpv for raising to a higher level condensate formed at said heat receiving part, said pump including a casing having an inlet for the warm condensate, structure within said casing providing a chamber and a rotatable impeller therein, the bottom wall of said chamber having an opening through which condensate passes into said chamber, and a riser tube communicating with said chamber and through which condensate is raised to the higher level, said structure including a. skirt extending downwardly from the bottom wall of said chamber to form a pocket, and a lip about said opening extending downwardly into said pocket.

8. In refrigeration apparatus, -a heat receiving part, a source of steam, a conduit for conducting steam from said source to said heat receiving part, a device for controlling flow of steam from said source to said heat receiving part, structure including a pump for raising to a higher level condensate formed at said heat receiving part, a well associated with said structure and into which warm condensate overflows when said pump fails to operate, and an expansible fluid thermostat for controlling said device, said expansible fluid thermostat including a thermal bulb located in said well and adapted to be heated by condensate overflowing therein.

9. In refrigeration apparatus, a heat receiving part provided with a chamber, a steam boiler, a heater for supplying heat to said boiler, a conduit to conduct steam from said boiler to said chamber to effect heating of said heat receiving part, the bottom part of said chamber being below the surface level of water maintained in said boiler, structure for returning to said boiler condensate formed in said chamber and collecting in the bottom part thereof, said structure including a pump for raising condensate from one level to a, higher level, and a device operable to reduce the rate at which said heater supplies heat to said boiler, said device being operable responsive to a condition produced as a result of said pump becoming inefiective to raise liquid from said one level to said higher level at a sufliciently rapid rate.

10. Inrefrigeration apparatus, a heat receiving part provided with a chamber, a steam boiler, a heater for supplying heat to said boiler, 'a conduit to conduct steam from said boiler to said chamber to effect heating of said heat receiving part, the bottom part of said chamber being below the surface level of water maintained in said boiler, structure for returning to said boiler condensate formed in said chamber and collecting in the bottom part thereof, said structure including a pump for raising condensate from one level to a higher level, and a device for reducing the rate at which said heater supplies heat to said boiler, said device being operable responsive to a rise in temperature afiected by warm condensate When said pump becomes ineffective to raise condensate from said one level to said higher level at a sufiiciently rapid rate.

, -11. In refrigeration apparatus a generator,

a steam boiler, a conduit to conduct steam from said boiler to said generator to eifect heating of the latter, a pump connected to said generator for raising condensate formed in said generator to a higher level, and a conduit for conducting raised condensate to said boiler, said pump comprising a casing forming a chamber, a rotatable impeller in said chamber, said casing having an opening forming an inlet through which the condensate enters said chamber, and means forming a pocket adjacent the inlet and in communication therewith and the condensate flowing to the chamber for confining and muflling noise Droduced during operation of said pump.

SVEN W. E. I ANDERSSON.

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