US3293881A

US3293881A - Means for transferring fluids in an absorption refrigeration system

Info

Publication number: US3293881A
Application number: US458841A
Authority: US
Inventors: Frank M Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-05-21
Filing date: 1965-05-21
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27

Description

27, .1965 F. M. WALKER 93, 81

MEANS FOR TRANSFERRING FLUIDS IN AN ABSORPTION REFRIGERATION SYSTEM Filed May 21, 1965 1 N VENTOR.

United States Patent 3,293,881 MEANS FOR TRANSFERRING FLUIDS IN AN ABSORPTION REFRIGERATION SYSTEM Frank M. Walker, sass NW. 46th, Oklahoma City, Okla. 73112 Filed May 21, 1965, Ser. No. 458,841 9 Claims. (Cl. 62476) This invention relates to absorption refrigeration systems and in particular to means for pumping fluids from the low pressure portion to the high pressure portion of a two pressure absorption refrigeration system.

In the conventional two pressure absorption refrigeration system, circulation of the refrigerant fluid throughout the system is accomplished by the pressure differentials between different portions of the system. At one point in such a system, conventionally at the generator, energy is introduced to the system in the form of heat at elevated temperature providing a high pressure refrigerant vapor conventionally delivered to a condenser wherein the vapor is condensed to a liquid. The liquifled refrigerant is then delivered to an evaporator wherein it evaporates, drawing the heat of vaporization from the exterior of the refrigeration system and thereby effecting the desired refrigeration effect. The low pressure vaporized refrigerant is delivered from the evaporator to an absorber wherein it is absorbed by a liquid and is delivered from the absorber to the generator as a solution to be reheated to again provide high pressure refrigerant vapor to begin the cycle over again. The present invention is concerned with a new and improved means for use in such an absorption refrigeration system for pumping the low pressure solution from the absorber to the generator against the high pressure of the vaporized refrigerant therein.

A principal feature of the invention is the provision of a new and improved means for pumping refrigerant in an absorption refrigeration apparatus.

Another feature is the provision of such a pumping means in an absorption refrigeration system having a first portion containing high pressure fluid and a second portion containing low pressure fluid, the pumping means including a pump connected between the first and second portions of the system for pumping fluid through and between the high pressure portion and low pressure portion, and means using a portion of the energy of the high pressure fluid for operating the pump.

A further feature of the invention is the provision of such a pump means which is simple in design and economically constructed, having few moving parts, thus providing extended maintenance-free service.

Still another feature is the provision of such a pump means arranged for continuous functioning notwithstanding fluid pressure variations within the system due to ambient temperature changes.

Another feature is the provision of a pumping mechanism which also serves as the pressure reducing valve for controlling flow of the absorption fluid from the generator to the absorber.

A yet further feature of the invention is the provision of such pump means which utilizes effectively minimum power, and which is substantially silent in operation.

Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a schematic view of a refrigeration system including a pump means embodying the invention, the pump means being shown as near the end of one half cycle of operation thereof. FIGURE 2 is a view of the pump shown in FIGURE 1 but with the pump means shown as near the end of the other half cycle of operation thereof.

In the embodiment of the invention as disclosed in the drawing, an absorption refrigeration system generally designated 10 includes a generator 11, a condenser 12, an evaporator 13, and an absorber 14, all of conventional construction.

Illustratively, the refrigerant may comprise ammonia and the liquid absorbent for absorbing the refrigerant in,

the system may comprise water. The present invention is concerned with a new and improved pump generally designated 15 for pumping water which is rich in ammonia refrigerant, hereafter referred to as x -liquid, from the absorber 14 to the generator 11 wherein the x -liquid is heated by the burner 69 to vaporize the ammonia refrigerant for delivery through conduit 64 to the condenser 12 where it is condensed to liquid. The condensed refrig erant is delivered from the condenser 12 to restrictor tube 49 which reduces the pressure of the liquid ammonia as it flows into the evaporator 13 where it vaporizes and flows through conduit 68 into the absorber 14 where it is absorbed by the solution therein.

The water which is Weak in ammonia refrigerant as a result of vaporizing the ammonia vapor therefrom, and which is hereafter refered to as x -liquid, is delivered from the generator 11 through a portion of the pump means 15 wherein a portion of the high pressure vapor energy in the generator 11 is utilized hydraulically for operating the pump means 15 through one half cycle. Similarly, high pressure vapor from the generator 11 is delivered directly through another portion of the pump means 15 utilizing a portion of the high pressure vapor energy in the generator 11 directly for operating the pump means 15 through the other half cycle.

Control of cycling the pump means 15 is obtained by means of a suitable conventional electric timer 16 for continued alternate opening and closing of selected solenoid valves 19, 2t), 29 and 34 at preselected time intervals to effect a predetermined g.p.m. rate of delivery by the pump means 15. More specifically, pump means 15 includes a pump 18;

solenoid valves

19, 20, 29 and 30;

check valves

55, 57, 61 and 63; and electric timer 16. The outer housing of pump 18 is defined by a first cylindrical portion 21 defining a first space 21a and a second portion 22, diametrically larger but having the same length of portion 21, defining a second space 22a. A partition 34 separates space 21a from space 22a. A piston 23 is slidable in housing portion 21 and an increased diameter piston 25 is slidable in housing portion 22. A shaft 28, slightly longer than either space 21a or 22a, passes through partition 34 and is fastened at one end to piston 23 and the other end fastened to piston 25. As shown, piston 23 is slidably sealed to housing portion 21 by a piston ring 32, piston 25 is slidably sealed to housing portion 22 by a piston ring 31, and shaft 28 is slidably sealed to partition 34 by a shaft seal 35.

Low pressure x -liquid is delivered from absorber 14 into space 22a of pump 18 between piston 25 and partition 34 by means of a conduit 54 provided with a check valve 55 precluding reverse flow therethrough. This space will hereinafter be referred to as space A. The x -liquid is delivered from space A of pump 18 to generator 11 by means of a conduit 56 leading from space A and provided with a check valve 57 precluding reverse flow therethrough. Low pressure x liquid is also delivered from absorber 14 into space 21a of pump 18 between piston 23 and partition 34 by means of conduits 54 and 60 provided with a check valve 61 precluding reverse flow therethrough. This space will hereinafter be referred to as space B. The x -liquid is delivered from space B of pump 18 to the generator 11 by means of

conduits

62 and 56 leading from space B and provided with a check valve 63 precluding reverse flow therethrough. High pressure x liquid is delivered from generator 11 into space 22a of pump 18 between piston 25 and end wall 36 by means of a conduit 58 and provided with a solenoid valve 20 controlling flow therethrough. This space will hereinafter be referred to as space C. The x -liquid is delivered from space C of pump 18 to the absorber 14 by means of a conduit 59 leading from space C and provided with a solenoid valve 19 controlling flow therethrough. High pressure vapor is delivered from the generator 11 into space 21a of pump 18 between piston 23 and end wall 65 by means of conduits 64 and 66 and provided with a solenoid valve 30 controlling flow therethrough. This space will hereinafter be referred to as space D. The high pressure vapor is released from space D of pump 18 to the absorber 14 by means of

conduits

67 and 68 leading from space D and provided with a solenoid valve 29 controlling flow therethrough.

The cycle of operation of the refrigeration system is initiated by supplying heat energy, such as burner 69, to the generator 11 and electrical energy through lines L1 and L2 to the timer 16. The heat of burner 69 applied to the generator 11 produces a high vapor pressure in the generator 11 and condenser 12 as compared to a lower vapor pressure present in the evaporator 13 and absorber 14. Timer 16 cyclically supplies electrical energy simultaneously through lines H1 and H2 to solenoid valves and 29, opening them for a preselected time, and then reverses supplying electrical energy simultaneously through lines H1 and H3 to

solenoid valves

19 and 30, opening them for a preselected time. It is to be noted that

solenoid valves

19, 20, 29 and 30 are opened when energized and olosed when de-energized. Also, the combination of paired

solenoid valves

19 and 20 together with T 70 co-act to form a three-way valve. Similarly, solenoid valves 29 and 30 together with T 71 co-act to form a three-way valve. Although I have shown the preferred form, it is understood that any type of controllable three-way valve may be substituted. For in stance, pneumatic or hydraulically operated three-way valves could be used in place of the paired solenoid valves shown and described.

Assuming the timer 16 has initiated the energizing of solenoid valves 20 and 29, opening them, high pressure x -liquid enters space C from the generator 11, while at the same time, high pressure vapor already present in space D is released into the absorber 14. The difference of these new opposing pressures, in space C and space D, acting on the opposite ends of shaft 28, produce a thrust on shaft 28, forcing the movement of pistons 23 and downward. During the downward movement of

pistons

23 and 25, x -liquid in space A is forced into the generator 11 through check valve 57 and conduit 56, while at the same time, x -liquid is drawn from the gen erator 11 into space C through conduit 58, solenoid valve 20 and T 70. Also, during the downward movement of

pistons

23 and 25, x -liquid is drawn into space B through conduits 54 and 60 and check valve 61 while at the same time, vapor in space D flows into the absorber 14 through T 71 and solenoid valve 29,

conduits

67 and 68. At the end of the downward movement of

pistons

23 and 25, the pump has the position shown in FIGURE 1. The timer 16 now reverses, according to a preselected time interval, which initiates the energizing of solenoid valves 19 and 390 through lines H1 and H2, opening them. High pressure vapor enters space D through conduits 64 and 66, solenoid valve and T 71. The hydraulically high pressure x -liquid in space C immediately becomes low pressure hydraulic x -liquid. The difference of these new opposing pressures in spaces C and D, acting on the opposite ends of shaft 28, produce thrust on shaft 28, forcing the movement of the

pistons

23 and 25 upward. During the upward movement of

pistons

23 and 25, x liquid is forced out of space C into the absorber 14 through T 70, solenoid valve 19 and conduit 59, while at the same time, x -liquid is drawn into space A from the absorber 14 through conduit 54 and check valve 55. Also, during the upward movement of

pistons

23 and 25,

x -liquid is forced out of space E into the generator 11 through check valve 63 and

conduits

62 and 56.

It should be noted that spaces 21a and 22a in pump 18 are so proportioned that a larger volume is provided for pumping x -liquid from the absorber 14 to the generator 11 than is provided for pumping x -liquid from the generator 11 to the absorber 14. This is necessary because the volume of liquid in the generator 11 is constantly decreasing, while at the same time, the volume of liquid in the absorber 14 is substantially increasing an equal amount during the operation of the refrigeration system, due to the flow of ammonia through the condenser 12 and evaporator 13 as well as through chamber D of pump 18. By utilizing both space A and space B for moving x -liquid from the absorber 14 to the generator 11, but utilizing only space C for moving x -liquid from the generator 11 to the absorber 14, a simple and accurate means is provided to automatically balance the liquid levels in the absorber 14 and generator 11 at all times during operation of the refrigeration system. Also, it should be noted that it is possible to use either a preselected or a variable g.p.m. rate of delivery by pump means 15. The thrust developed by the shaft 28 will automatically increase or decrease with an increase or decrease of ambient temperature. For example, the pressure differential between the generator-condenser and the absorber-evaporator of the system will range from 190 p.s.i.g. at 70 F. to 260 p.s.i.g. at F. ambient. The thrust developed by shaft 28 is calculated by the formula, T=A(P1P2), where T thrust, A='cross sectional area of the shaft 28, Pl=pressure of the generator-condenser, and P2=pressure of the evaporator-absorber. Therefore, the selection of a .25 sq. in. cross sectional area shaft 28 would develop a thrust having a range of 47 /2 lbs. at 70 F. ambient to 65 lbs. at 95 F. ambient. Therefore,

pistons

23 and 25 are forced to move faster by the shaft 28 as the ambient temperature increases or vice-versa. It is shown by the above that it is possible to provide a dual modulating control (not shown) for simultaneously increasing or decreasing the speed of timer 16 and the B.t.u. input to burner 69 in response to increased or decreased load demand to automatically modulate the output of the refrigeration system. Although I have shown the preferred arrangement in the drawing and in the description of a timer 16 having a preselected constant speed for control of said

solenoid valves

19, 20, 29 and 30 to produce a predetermined constant g.p.m. rate of delivery of pump means 15, it is used merely for simplicity of description and is not meant to limit the spirit or scope of the invention. Also, while I have shown a single embodiment of the invention as herein illustrated and described, it will be understood that modifications may be made in the construction and arrangement of elements without departing from the spirit or scope of the invention. For instance, diaphragms may be substituted for the

pistons

23 and 25 shown. Also, any combination of refrigerant and absorbent for the refrigerant may be substituted for the ammonia and water herein described. Therefore, without limitation in this respect, the invention is defined by the following claims.

I claim:

1. In an absorption refrigeration system having a first portion including a generator containing high pressure vapor and solution and a condenser containing high pressure refrigerant vapor and liquid, and a second portion including an absorber containing low pressure vapor and solution and an evaporator containing low pressure refrigerant vapor and liquid, apparatus comprising: a pump having means defining a first chamber and a first displacement member reciprocable in said first chamber for displacement of fluid in said chamber, a second chamber coaxially aligned with the said first chamber and being diametrically smaller than said first chamber and a second displacement member reciprocable in said second chamber for displacement of fluid in said chamber; a shaft slidably passing through the common end walls of said chambers and fastened at one end thereof to said first displacement member and fastened at the other end thereof to the said second displacement member for reciprocating said displacement members as a unit; first flow passage means communicating with said first chamber at one side of said first displacement member and with the said absorber and said generator for delivering a predetermined volume of x -liquid from said absorber to said first chamber during one movement of the said shaft and displacement members and delivering the said volume of x -liquid therefrom to said generator during the opposite movement of said shaft and displacement members; a second flow passage means communicating with said first chamber at the opposite side of the said first displacement member and with the said absorber and said generator and including a valve responsive to electrical impulse for delivering a predetermined volume of high pressure x -liquid from said generator to said first chamber at the opposite side of the said first displacement member during said opposite movement of the said shaft and displacement members and delivering said volume of x -liquid therefrom to said absorber during said one movement of the said shaft and displacement members; a third flow passage means communicating with the second chamber at one side of the said second displacement member and with the said absorber and said generator for delivering a predetermined volume of x -liquid from said absorber to said second chamber during said opposite movement of said shaft and displacement members and delivering said volume of x -liquid therefrom to said generator during said one movement of the said shaft and displacement members; a fourth flow passage means communicating with said second chamber at the opposite side of the said second displacement member and with the said generator and absorber and including a valve responsive to electrical impulse for delivering high pressure vapor to said second chamber at the opposite side of the said second displacement member during said one movement of the said shaft and displacement members and delivering the high pressure vapor therefrom to said absorber during said opposite movement of said shaft and displacement members; and an electric timer means cyclically energizing said valves connecting said first and second chambers alternately and oppositely with the said high pressure and said low pressure portions of the system to reciprocate the said shaft and displacement members.

2. In an absorption refrigeration system having a first portion including a generator containing high pressure vapor and solution and a condenser containing high pressure refrigerant vapor and liquid, and a second portion including an absorber containing low pressure vapor and solution and an evaporator containing low pressure refrigerant vapor and liquid, apparatus comprising: a pump for circulating solution through and between the first and second portions of the system and including a first closed cylinder having an outer end and an inner end and a port at the outer end and an inlet and outlet adjacent the inner end; a first reciprocable piston in the first cylinder forming an outer chamber and an inner chamber therein; a second closed diametrically smaller cylinder than said first cylinder having an outer end and an inner end and a port at the outer end and an inlet and outlet adjacent the inner end co-axially sealed to the inner end of the said first cylinder; a second reciprocable piston in the second cylinder forming an outer chamber and an inner chamber therein; a shaft slightly longer than either of said first or second cylinders slidably passing through the common end wall between said cylinders and having one end thereof fastened to the said first piston and the other end thereof fastened to the said second piston effecting united inverse volume changes of the said outer chambers and inner chambers of the said cylinders upon reciprocation of the said pistons and shaft; a first flow control valve operationally responsive to electrical impulse having an inlet communicating with the high pressure solution in the said generator and an outlet communicating with the said absorber and a port communicating with the said port to the outer end of the said first cylinder for selectively delivering a predetermined volume of solution from the said generator to the outer chamber of the said first cylinder upon one movement of the said pistons and shaft and delivering said volume of solution from the said outer chamber to the said absorber upon the opposite movement of the said pistons and shaft; a second flow control valve operationally responsive to electrical impulse having an inlet communicating with the high pressure vapor in the said condenser-generator and an outlet communicating with the said absorber and a port communicating with the said port to the outer end of the second cylinder for selectively delivering a predetermined volume of high pressure vapor from the said generator to the outer chamber of the said second cylinder upon said opposite movement of the said pistons and shaft and delivering the said volume of vapor from the said outer chamber to the said absorber upon the said one movement of the pistons and shaft; a first check valve having an inlet communicating with the absorber and an outlet communicating with the inlet to the inner chamber of the said first cylinder for flow of solution from the said absorber into the said inner chamber upon said opposite movement of the pistons and shaft and precluding reverse flow therethrough; a second check valve having an inlet communicating with the absorber and an outlet communicating with the inner chamber of the said second cylinder for flow of solution from the said absorber into the said inner chamber upon said one movement of the pistons and shaft and precluding reverse flow therethrough; a third check valve having an inlet communicating with the inner chamber of the said first chamber and an outlet communicating with the said generator for flow of solution from the said inner chamber to the generator upon the one movement of the said pistons and shaft and precluding reverse flow therethrough; a fourth check valve having an inlet communicating with the inner chamber of the said second chamber and an outlet communicating with the said generator for flow of solution from the said inner chamber to the generator upon the opposite movement of the said pistons and shaft and precluding reverse flow therethrough; and an electric timer switch for selectively energizing said control valves for preselected time intervals to connect said first cylinder outer chamber alternately to the said high pressure solution in the said generator and the said absorber and oppositely connecting the said second cylinder outer chamber alternately to the said high pressure vapor in the generator-condenser and the said absorber for utilizing a portion of the high pressure vapor energy produced in the system to alternately develop thrust on the opposite ends of the said shaft so as to reciprocate the said pistons.

3. The combination with an absorption refrigeration system of the differential pressure type wherein a solution of refrigerant and an absorbent circulate, a generator disposed in the high pressure side of the system, an absorber disposed in the low pressure side of the system, conduits forming a circuit for flow of refrigerant and absorbent through and between the generator and absorber, of a pump interposed in said circuit for forcing circulation of fluids through the circuit, comprising a first solution displacement means, a second solution displacement means, a power piston interconnecting the said first and second solution displacement means and having one end thereof exposed to existing pressures in the first solution dis placement means and the opposite end thereof exposed to existing pressures in the second solution displacement means, and means for alternately communicating one solution displacement means to the high pressure side of the system while simultaneously communicating the other solution displacement means to the low pressure side of the system to actuate the piston and solution displacement means by system forces acting on opposite ends of the piston.

4. The invention set forth in claim 3, wherein the said last mentioned means includes electrically operated valve means controlling communication between the said first and second solution displacement means and the high and low pressure sides of the system, an electric circuit for operating said valve means, and an electric cam actuated switch in said circuit to control the circuit.

5. In an absorption refrigeration system having a first portion containing high pressure fluid and a second portion containing low pressure fluid, apparatus comprising: a double action pump for pumping fluid through and between the first and second portions of the system including a housing having a partition therein forming a first chamber having an inlet and an outlet adjacent the partition, and a port opposite the partition, and a second chamber having an inlet and an outlet adjacent the partition, and a port opposite the partition; a first fluid displacement piston in the first chamber reciprocable toward and from the said partition; a second fluid displacement piston in the second chamber reciprocable toward and from the said partition; first passage means for delivering fluid from the said second portion of the system to said inlets upon spacing of said pistons from said partition; a second passage means for delivering fluid from said outlets to said first portion of the system upon juxtaposing of said pistons toward said partition; a power piston slidably passing through the said partition and fastened to the said fluid displacement pistons; and means for selectively applying system pressure differentials on opposite ends of said power piston for cyclically reciprocating said fluid displacement pistons at preselected time intervals.

6. In an absorption refrigeration system as defined in' claim 5 further characterized by said last mentioned means comprising; a third passage means including a control valve for selectively communicating the port in the said first chamber with either of the said first or second portions of the system; a fourth passage means including a control valve for selectively communicating the port in the said second chamber with either of the said first or second portions of the system; and control means for selectively controlling said control valves.

7. In an absorption refrigeration system as defined in claim 6 further characterized by said control valve being electrically operated.

8. In an absorption refrigeration system as defined in claim 7 further characterized by said control means comprising an electric circuit including the said electrically operated valves, and an electric timer actuated switch in the said circuit to control the circuit.

9. In an absorption refrigeration system of the differential pressure type wherein a solution of refrigerant and an absorbent circulate, refrigerant vapor generator means having a vapor outlet, a solution inlet and a solution outlet, absorber means having a solution inlet, solution outlet and a refrigerant vapor inlet, a condenser having an inlet connected to the vapor outlet of said generator means and an outlet; an evaporator having an inlet connected to said condenser outlet and an outlet connected to said re frigerant vapor inlet of said absorber means, a first pump means, a second pump means, said first and second pump means conveying solution from said absorber solution outlet to said generator solution inlet, said first pump means having a driving fluid inlet connected to the solution outlet of said generator means and a driving fluid outlet connected to the solution inlet of said absorber means, said second pump means having a driving fluid inlet connected to the vapor outlet of said generator means and a driving fluid outlet connected to the refrigerant vapor inlet of said absorber means, and means interconnecting the said first and second pump means for alternately operating one said pump means by forces developed in the other said pump means.

References Cited by the Examiner UNITED STATES PATENTS 2,929,222 3/1960 Lang 62487 X 2,930,204 3/1960 Lang 62--488 X 3,046,756 7/1962 Whitlow et al. 62141 FOREIGN PATENTS 593,548 3/1934 Germany. 840,249 5/1952 Germany. 708,482 5/1954 Great Britain.

LLOYD L. KING, Primary Examiner.

Claims

3. THE COMBINATION WITH AN ABSORPTION REFRIGERATION SYSTEM OF THE DIFFERENTIAL PRESSURE TYPE WHEREIN A SOLUTION OF REFRIGERANT AND AN ABSORBENT CIRCULATE, A GENERATOR DISPOSED IN THE HIGH PRESSURE SIDE OF THE SYSTEM, AN ABSORBER DISPOSED IN THE LOW PRESSURE SIDE OF THE SYSTEM, CONDUITS FORMING A CIRCUIT FOR FLOW OF REFRIGERANT AND ABSORBENT THROUGH AND BETWEEN THE GENERATOR AND ABSORBER, OF A PUMP INTERPOSED IN SAID CIRCUIT FOR FORCING CIRCULATION OF FLUIDS THROUGH THE CIRCUIT, COMPRISING A FIRST SOLUTION DISPLACEMENT MEANS, A SECOND SOLUTION DISPACEMENT MEANS, A POWER PISTON INTERCONNECTING THE SAID FIRST AND SECOND SOLUTION DISPLACEMENT MEANS AND HAVING ONE AND THEREOF EXPOSED TO EXISTING PRESSURES IN THE FIRST SOLUTION DISPLACEMENT MEANS AND THE OPPOSITE END THEREOF EXPOSED TO EXISTING PRESSURES IN THE SECOND SOLUTION DISPLACEMENT MEANS, AND MEANS FOR ALTERNATELY COMMUNICATING ONE SOLUTION DISPLACEMENT MEANS TO THE HIGH PRESSURE SIDE OF THE SYSTEM WHILE SIMULTANEOUSLY COMMUNICATING THE OTHER SOLUTION DISPLACEMENT MEANS TO THE LOW PRESSURE SIDE OF THE SYSTEM TO ACTUATE THE PISTON AND SOLUTION DISPLACEMENT MEANS BY SYSTEM FORCES ACTING ON OPPOSITE ENDS OF THE PISTON.