US1993478A - Ejector control equipment - Google Patents

Description

H. M. GRAHAM EJECTOR CONTROL EQUIPMENT Filed July 29, 1952 March 5, 1935. 1,993,478

INVENTOR BY .JfiroZJM rdfiafil A TTORNEY-S Patented Mar. 5, 1935 i UNITED STATES rat-Eur OFFICE EJECTOR CONTROL EQUIPMENT Harold M. Graham, Buffalo, N. Y., assignor, by

mesne assignments, to Ross Heater & Manufacturing Company, 1110., Buffalo, N. Y., acorporation of New York Application July 29,1932, Serial No. 625,912

6 Claims. ((1257-24) This invention relates to ejector-equipment of 6 and is introduced into the chamber in the'form the t pe in which the rate of flow of steam to the of a spray, a predetermined volume of refrigerant ejectors is varied in accordance with the tembeing maintained in the chamber by a float conperature or pressure of the medium in which controlled valve '7. The refrigerant may be withdensation of the steam is effected. It is the drawn from the cooling chamber through a pipe 5 practice to employ condensers in connection with 8 by a suitable pumps, the latter being available the ejectors, a vacuum as high as'prac'tical being to circulate the refrigerant through the cooling maintainedin the condensers. The degree of coils of the apparatus. In this connection it'is vacuum that can be maintained in a condenser is understood, of course, that the liquid which is 10 dependent, among other factors, upon the teniintroduced into the cooling chamber through 10 perature of the cooling water which is available. the pipe 6 maybe the liquid whichis caused to The water that ordinarily is available is subject circulate through the cooling coils or it may be to seasonal changes in temperature and hence obtained from a remote source. the temperature and corresponding pressure that The refrigerating medium in the chamber '5 i prevail in the condenser will vary. In most inloweredto and maintained at a predetermined l5 stallations the work that must be performed is temperature by maintaining a predetermined also variable. The equipment, therefore, must vacuum in the said chamber. To this end the be so designed that it is capable of functioning chamber 5 is in communication by way of a pipe in the manner requiredunder the most adverse extension 10 with an ejector 11. Steam is delivconditions, for example, when the work to be perered to the nozzles 12 of the ejector from a steam 20 formed is greatest and when the temperature of supply line 13. In its passage through the throat the cooling water available is highest. Equip- 14 of the ejector the steam entrains that portion ment of this general type has heretofore been of the liquid which vaporizes in the chamber 5 prohibitive for most purposes owing to the eX- and carries it into a condenser 15. A vacuum cessive operating costs which result from the preferably of the order of 27 inches of mercury 25 large consumption of steam during light load is maintained in the said condenser by an ejector p r ds. 16, the latter being connected to the steam sup- The principal object of the present invention is ply line 13 by branch pipes 17 and 18. Condensate to overcome the above objection, this object conmay be withdrawn from the hot well 15a of the templating a construction wherein the consumpcondenser by a suitable pump 16a. The ejector 30 tion of steam is maintained at a minimum 16 discharges into the upper half of an auxiliary throughout the entire range of operating loads condenser 19, a vacuum being maintained in the and conditions. said half of the condenser by an ejector 20 which Afurther object is to provide equipment which is connected to the steam supply line 13 by a is highly efficient overa wide range of operating branch pipe 21 and the branch pipe 17. The ejec- 35 loads and conditions. tor 20 discharges into the lower half of the con- The invention is characterized by features denser 19, which half isin communication with which render it of particular advantage in 0011- the atmosphere through a connection 22. The nection with refrigerating systems, air conditiOnhead 23 of the condenser 15 is formed with inlet -10 ing apparatus, water cooling'and similar Systems. and outlet chambers 24 and 25 respectively. The It is to be understood, however, that the adformer is connected to a pipe line 26 by which vantages of the invention may be obtained in cooling water is introduced into the inlet chamconnection with other types of apparatus, the her 24. The water passes from the inlet chamber uses specifically noted being by way of example through those tubes in the lower half of the conydenser into the chamber provided by the head 45 Theinvention is illustrated in the accompany- 2'7 and from the latter flows through the tubes ing w g in wlL'ch': in the upper half of the condenser into the out- The single figure is a diagrammatic view of-a let chamber 25. From the outlet chamber the refrigerating" system in which features of the water is conducted by a pipe 28 to a point of dis- 09 invention are incorporated. pos'al.

The invention is illustrated in connection with Cooling water is withdrawn from the supply a refrigerating system, the latter being sufpipe 26 and is conducted by a branch pipe 29 to' ficiehtly indicated by a showing of the cooling the inlet chamber 30 of the condenser 19. The chamber 5 thereof. The refrigerating medium cooling water is passed through the tubes of the is conducted. to the cooling chamber 5 by a pipe condenser 19 in a manner similar to that deall) scribed in connection with condenser 15. From the outlet chamber 31 the water is conducted by a pipe 32 to the main discharge line 28.

The vacuum, and hence temperature of the refrigerating medium, that can be maintained in the chamber is dependent, among other factors, upon the vacuum that is maintained in the condenser 15. On the other hand the vacuum that can be maintained in the condenser is dependent to a large degree upon the temperature of the cooling water which is circulated through the tubes of the condenser. Inasmuch as there will, in most instances, be seasonal variations in the temperature of the cooling water, the vacuum in the cooling chamber will, assuming that the flow of steam through the ejector is uniform, vary correspondingly. It will be apparent that variations in the rate of withdrawal of the refrigerating medium imposes corresponding variations in the load upon the equipment. In this connection it is understood, of course, that a decrease in the degree of vacuum in the condenser 15 is in effect an increase in the load upon'the equipment and vice versa. In order to compensate for variations in the load upon the equipment which, of course, includes variations in the degree of vacuum in the condenser 15, means is provided whereby the flow of steam to the ejector regulated in accordance with the vacuum that is maintained in the condenser 15. To this end the steam supply line 13 includes a valve 33. The latter is connected by a pipe 34 with the condensing chamber of the condenser 15. The valve 33 is opened more or less as the vacuum in the condenser varies. Thus, as the absolute pressure in the condenser increases, and hence the back pressure against which the ejector operates is increased, the valve 33 is opened correspondingly to increase the amount of steam that is delivered to the ejector. On the other hand as the absolute pressure decreases, and-hence as the back pressure against which the ejector operates decreases, the valve 33 closes correspondingly to reduce the amount of steam delivered to the ejector.

In accordance with the invention means is provided whereby the velocity of flow of the motive fluid into the condenser 15 is maintained at substantially a constant value during regulation of the flow of steam to the ejector in the manner described. For this purpose a valve 35 is arranged in the throat of the ejector, the said valve co-operating with the walls of the throat to provide an annular passage through which the steam passes from the ejector into the condenser. The valve 35 is carried upon a stem 36 which is arranged axially of the throat of the ejector. The stem is slidably mounted in a web-like support 3'7. Communication from the ejector into the condenser is by way of an inlet connection 38.

The stem 36 extends through a wall 39 of the said connection, leakage past the wall 39 being prevented by a stufiing box 40. A cylinder 41 is suitably secured to the wall 39 of the inlet connection 3S and a piston 42 is arranged in thesaid cylinder, the piston being connected to the stem 36. A spring 43 is arranged about the stern between the piston and an inner wall 44 of the cylinder.. Movement of the piston 42 toward the wall 44 is resisted to a predetermined degree by the said spring, the latter tending to move the piston toward the opposite end of the cylinder. The cylinder 41 is in communication with the steam supply line 13 through a pipe 45 which is connected to the latter between the valve 33 and the ejector. Hence as the rate at which steam is delivered to the ejector varies the piston is moved more or less toward the cylinder wall 44 against the action of the spring 43, the extent of movement corresponding to the rate at which steam is delivered to the ejector.

Movement of the piston 42 in either direction is transmitted by the stem 36 to the valve 35. It will be noted that that portion of the throat 14 of the ejector which surrounds the valve 35 tapers from the point where the throat is connected to the inlet connection 38 of the condenser toward the nozzles 12. Hence as the latter is moved axially of the throat toward the nozzles the crosssectional area of the annular passage defined by the valve and the walls of the throat is progressively decreased while as the valve 35 is moved in the opposite direction the cross-sectional area of the annular passage is progressively increased. The position of the valve 35 is determined by the amount of steam that is delivered to the ejectors 12. Thus, when the valve 33 is regulated so that a relatively large amount of steam is being delivered to the ejector, the valve 35 will be moved toward the nozzles 12 to decrease the cross-sectional area of the passage through the ejector while, on the other hand, when the valve 33-is regulated to admit a relatively small amount of steam to the ejector the valve 35 will be moved away from the nozzles to increase the cross-sectional area of the passage through the ejector. By controlling the cross-sectional area of the passage through the ejector in the manner described the flow of steam into the condenser 15 is maintained at substantially a uniform velocity despite variations in the rate at which the steam is delivered to the ejector. This has the advantage that the equipment is capable of operating efliciently over a wide range of loads, that is to say steam is delivered to the ejector at a rate which is adequate, but which is not more than adequate, to maintain the refrigerating medium at the predetermined temperature, the valve 35 being automatically adjusted to vary the crosssectional areaof the passage through the ejector in accordance with the rate at which the steam is delivered to the ejector.

As the vacuum that can be maintained in the condenser 15 will vary with variations in the temperature of the cooling water, the flow of steam to the ejector may be regulated by the latter instead of in the manner described.

It will be apparent from the foregoing that in operation the temperature of the refrigerating medium is at all times maintained at the temperature desired with a minimum consumption of steam, and that operating costs, therefore, are maintained at a minimum during light loads as Well as peak loads.

I claim as my invention:

1. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, a steam supply line for said ejector, a condenser into which said ejector discharges, means for maintaining a vacuum in said condenser, means responsive to the degree of vacuum in said condenser for regulating the supplyof steam to said ejector and means responsive to the pressure of the steam in said supply line for automatically regulating the cross-sectional area of the passage through said ejector.

2. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, a condenser, a

converging-diverging conduit into one end of which said ejector discharges and which at its opposite end communicates with said condenser, means for maintaining a vacuum in said condenser, an element located in said conduit and co-operating with the walls thereof to provide a passage through which the steam passes to said condenser, means responsive to the degree of vacuum in said condenser for regulating the supply of steam to said ejector and means responsive to the pressure of the steam as supplied to said ejector for regulating the position of said element in said conduit to vary the cross-sectional area of said passage.

3. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, a steam supply line for said ejector, a condenser into which said ejector discharges, means for regulating the supply of steam to said ejector and means responsive to the pressure of the steam as supplied to said ejector for automatically regulating the cross-sectional area of the passage through said ejector.

4. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, a steam supply line for said ejector, a condenser into which said ejector discharges, a valve in said supply line for regulating the supply of steam to said ejector and means responsive to the pressure of the steam in said supply line between said valve and said ejector for automatically regulating the crosssectional area of the passage through said ejector.

5. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, an element in the throat of said ejector, said element co-operating with the walls of said throat to provide a substantially annular passage, a steam supply line for said ejector, a condenser into which said ejector discharges, means for regulating the supply of steam to said ejector and means responsive to the pressure of the steam as supplied to said ejector for automatically regulating the position of said element, whereby tovary the cross-sectional area of said annular passage.

6. In equipment of the type described, the combination of a chamber, an ejector for maintaining a vacuum in said chamber, an element in the throat of said ejector, said element co-oporating with the walls of said throat to provide a substantiaily annular passage, a steam supply line for said ejector, a condenser into which said ejector discharges, a valve in said supply line for regulating the supply of steam to said ejector and means responsive to the pressure of the steam in said supply line between said valve and ejector for automatically regulating the position of said element, whereby to vary the cross-sectional area of said annular passage.

HAROLD M. GRAHAM.

Images