Refrigerating apparatus

Abstract

Claims

Jan. 30,1940. A. D. ARR- 2,188,540 REFRIGERATING APPARATUS Filed July 14, 1938 INVENTOR Hzjz'edD-Ifazm HIS ATTORNEY. Patented Jan. 30, I9fl0 Alfred n. Km, Newark, N. 1., aslignor to Ingersoll-Rand Company. Jersey City, N. 1., a corporation of New Jersey Application Jul 'ii, 1m, Serial No. 219,175 10 Claims. a series of vaporizing chambers. An object of the invention is to provide plural chamber refrigerating apparatus wherein refrigerant may be passed throughone or more chambers while being chilled. apparatus having a multichamber evaporator wherein refrigerant supplied to the evaporator, when all the chambers are temporarily inactive.. is not heated thus permitting the refrigerant to leave the evaporator at substantially its supply temperature. A further object is to assure a continuous supply of refrigerant to an active refrigerating chamber and to obviate exposure of refrigerant to undue heating eifects in any inactive refrigerating chamber of a refrigerating apparatus. An additional object is to seal active'refrigerating chambers from inactive refrigerating chambers of a refrigerating apparatus. V A further object is to enable a refrigerating apparatus, comprising a plurality of evaporator chambers normally operating in series, to be operated at part load by shutting down any, one or more of the evaporators without shutting down the other chambers, and to simplify the cona top-wall 3 and a bottom wa1l l.A transverse partition 8 depends from the topwall 3 and extends to'a point near the bottom wall 4. This partition I serves, with the walls of the evaporator, to define a primary chamber 0 in the evaporator. similarly, the transverse partition I depending from the top wall 3 serves to define the secondary chamber 8., It will be noted that the partition 1 extends nearer. the bottom wall 4 thanthe partition. e The primary chamber I and the secondary chamber I are each provided-with means to reduce the pressuretherein in the form of an evacuator means 0, preferably of the ejector type and communicate" therewith through ports It Another object is to provide a refrigerating (ores-152) I formed in the top wall 3 of the evaporator. An evacuator actuating pressure medium such as steam is supplied to the evacuators 9 through the conduits ll connected to a source of supply (not shown). In order to control operation of the evacuators 9 valves I! are interposed between the conduits ii and the evacuators 9. By closing the valve I2 on the. primary chamber evacuator 9 the chamber 8 is rendered inactive and in the same 10 manner the secondary chamber 6 may be rendered inactive. V Both the evacuators I, when activated. discharge to a condenser ll of any suitable construction here shown as a tubular water cooled 16' type wherein cooling water] is admitted to the condenser l3 through the pipe l4 and withdrawn from the condenser II by means of the pipe II. The evacuators 8, when operating, withdraw vapor from the refrigerant in their re- 20 spective chambers through the ports I0 and discharge it with the evacuato'r actuating medium tothe condenser i3, thereby cooling the re-- frigerant. v'I'he pressure in the chambers t and-8 is considerably less thanthe pressure in the condenser II when the evacuators i are operating. If, for any reason, the valve I! for one of the evacuators I is closed, the pressure in the associated evaporator chamber will immediately rise to the same pressure as exists in the condenser i3. Liquid refrigerant such as water is supplied to the evaporator l by the conduit 31 and is withdrawn from the evacuator through the con-- duit It by the pump Ila. ,The conduit It has risers l1 and It opening into the primary chamber 8 and the secondary chamber 8 respectively. These risers .II and II are of sufficient height so that a liquid seal will be maintained in the riser at all times even in though a chamberis empty and inactive. During normal operation of the refrigerating apparatus, the riser It removes all the chilled refrigerant but in the event that the secondary chamber 8 is inactive, refrigerant may be reas moved from the primary chamber 8 through the riser II. In the'primary chamber I is a discharge well It or trap formed by the weir II, extending from the bottom wall 4 into the chamber 0, and the tram verse partition 2| dego' chambers are active, the refrigerant in well l8 will not be withdrawn from the primary chamber 6 through the well i 8 and the riser I! for the reason that the conduit 22 permits the well I! to be maintained under the same pressure as the pressure in the condenser l3. The liquid refrigerant supplied by the conduit 31 to the evaporator i is admitted to the primary chamber 8 through the well 23 defined by a weir 24, rising from a plate 25 spaced from and parallel to a bottom wall 4, and partition 8. The top of the weir 24 is considerably above the level of the refrigerant in the chamber'B and serves as an overflow means from which the refrigerant falls in a more or less divided state into the chamber 6 and is subjected to the reduced pressure in the chamber. A port 28 may be provided, if desired, near the top of the weir 24 to deliver refrigerant to the chamber and a suitable baflie 21 may also be provided adjacent the weir 24 in order to prevent entrainment of refrigerant in liquid state from the stream of vapor flowing to the evacuator 8. Under normal operating conditions, when the primary chamber 8 is active, refrigerant enters through the conduit 31 and flows through the well 23 over the top of weir 24 into the primary chamber where it is partially evaporated and chilled. The refrigerant, after being chilled in this cham ber, then flows through the passage 36 defined by the plate 25 and the bottom wall 4 of the evaporator to the secondary chamber 8 where further chilling occurs. The secondary chamber 8 is also provided with an inlet well indicated at 28 and defined by the transverse weir 29, rising from. the bottom wall 4 of the evaporator, and the partition 1. Any refrigerant that enters this well while the secondary chamber is active flows over the top of the weir 28 or through port 38 into the secondary chamber 8. This well 28 may, similar to well 23, be provided with a protecting baii'ie 3i. It will be noted that the weir 28 does not rise to as great a height as the weir 24. The height of weir 24, unlike the other weir, determines the static head of the refrigerant entering well 23 through the conduit 31. The height of weir 28 is fixed by the pressure in the evaporator chamber 8 and the pressure in the secondary chamber 8 as will be pointed out hereinafter. Between partitions 5 and I which define another control or by-pass chamber another transverse weir 32 rises from the plate 23 to form, with partition 3, and seal 33 and, with partition J, a seal 34. These seals are subjected to the pressure in the condenser l3 by a branch pipe 35 of the conduit 22. With this arrangement it is, therefore, apparent that refrigerant flowing from the primary chamber 6 to the secondary chamber 3, when bothchambers are active, is subjected to the pressure of the condenser through seal 34. Likewise, seal 33 is under the same presure. The operationof thenapparatus will now be described: Assuming that both evacuators 8 are operating and maintaining both chambers 8 and 8 active, refrigerant will enter through the conduit 31 and flow from the well 23 into the primary chamber. At the same time, refrigerant will flow into the seal 33 but, since the weir 32 is of such height that the pressure in the condenser is sufficient to prevent a flow of refrigerant over the top of the weir into the well '34 so long as the primary chamber 8 is active, the areas-1o only path for the refrigerant to follow leads directly into the primary. chamber 8. The chilled refrigerant in the primary chamber 6 cannot flow into the riser I! because the weir 20 is so designed that the condenser pressure will maintain refrigerant therein to form a seal in the well i9 as long as the secondary chamber 8 is active. The flow of the refrigerant, therefore, is through the passage 38 into the well 23 and to the chamber 8. The pressure maintained on the seal 33 by the condenser i3 is so much greater than the pressure maintained in the primary chamber 6 by its evacuator 9 that fluid cannot rise to flow over weir 32 and into the seal 34. Refrigerant in the secondary chamber 8 is withdrawn through the riser i8 and transmitted to a suitable utilization point (not shown) by the pump I81: and preferably thereafter returned to the evaporator by the conduit 31. If, for any, reason, one of the chambers is unnecessary for cooling the refrigerant, it is possible, by means of this apparatus, to maintain one chamber active while the other is inactive. First, if it is desired to operate the primary chamber 8 alone and hold the secondary chamber 8 inactive, the refrigerant enters the primary chamber 8 as was previously described. However, in this instance, the secondary chamber will be subjected to the pressure in the condenser i3, because its evacuator 8 is inactive, and the flow of refrigerant from the primary chamber 8 is prevented. Instead, the refrigerant will be bypassed to outlet conduit i6 via well i9 and flow therefrom into the riser II. Inasmuch as the bypass chamber between walls 2 and M and the chamber 8 are both at the pressure of condenser l3, the discharge ofchamber 6 will flow over weir 20 in preference to weir 28 because of the relative lowness of the weir 28. At such a time, the pressure in the secondary chamber 3 will force any refrigerant remaining therein out through the riser l8 but will be insufficient to force all of the refrigerant out of the riser l8 and thus a seal may be maintained in the riser l8. Secondly, if it is desired to operate the secondary chamber 8 alone without the primary chamber 8.. the refrigerant will'pass through the evaporator in a somewhat different manner. Since the primary chamber 8 is inactive, the condenser pressure maintained in the primary chamber 8 will equal that of the by-pass chamber between walls 3 and I, both being at the pressure maintained in condenser i3.- Refrigerant pumped into chambers 23 and 33 will rise equally in each and sincewall 32 is lower than wall 28, all of the refrigerant will flow over the former into sealing chamber 34 thereby by-passing chamber 8. Because the pressure in the by-pass chamber between walls 3 and I is higher than the pressure in well 23, the water level will :be sufficiently high to overflow weir 28 into chamber 3. The refrigerant is then removed from the secondary chamber 3 via conduit H to pump "a. In the event that both chambers 4 and I are renderedainactive to temporarily cut-oi! the capacity of'the apparatus, refrigerant will still enter the evaporator and flow therefrom. However, since the condenser pressure will then exist in both chambers 3 and 3, it will prevent the entrance of refrigerant to either chamber through their respective inlet wells 23 and 23, and there can be no spraying of the refrigerant into the chambers and consequently no heating of the refrigerant in either chamber. In such ill) heating and -as a result the refrigerant need not cooled refrigerant. an instance therefrigerant will flow over the weir 32 into seal 34, through the by-pass 36, over the bottom of chamber 6, into well l9 and thence to the riser ll. Obviously, there can be little or no heating of the refrigerant as it passes through the lower portion of chamber 8. Such an arrangement, therefore, permits the refrigerant to be recirculated through the evaporator without be recooled simply because it has been reheated in passing through the evaporator, thus insuring emciency of operation and obviating waste of the evacuator actuating medium. Furthermore, it is obvious that this advantage is attained without restricting the normal flow of refrigerant liquid through the apparatus and without the necessity of auxiliary valves to by-pass the refrigerant around the apparatus. The arrangement above described provides a most convenient apparatus to operate. Assuming that the evacuators Shave equal thermal capacity, the operator may reduce the capacity of the refrigerator by one-half by closing one or, the other of the valves l2 indiscriminately. The automatic by-passing of the large quantities of refrigerant with relatively slight exposure to vapors from the condenser prevents reheating of The evacuators may, if desired, be of unequal thermal capacity so that, depending upon which valve I2 is operated, the degree of partial capacity of the refrigerator may be varied. I claim: '1. In refrigerating apparatus, an evaporator having a primary chamber and a secondary chamber, means to reduce the pressure in the chambers and to selectively render any chamber inactive, inlet means for each chamber, means to supply refrigerant directly to the inlet means of the primary chamber when the primary chamber is active and directly without entry into the primary chamber to the inlet means of the secondary chamber when the primary chamber is inactive, means to supply refrigerant from the primary chamber to the inlet means of the secondary chamber when both chambers are active, means to remove refrigerant from the secondary chamber when the secondary chamber is active, and means to discharge refrigerant from the primary chamber when the secondary chamber is inactive. 2. In refrigerating apparatus, an evaporator having a primary chamber anda secondary chamber, means to reduce the pressure in the chambers and to selectively render'any chamber inactive, means to supplyrefrigerant directly to the primary chamber when the primary chamberis active and directly without entering an inactive chamber to the secondary chamber when the primary chamber is inactive, and means to supply refrigerant from the primary chamber to the secondary chamber when both chambers are active. 3. In refrigerating apparatus, an evaporator having a primary chamber and a secondary chamber, means to reduce the pressure in the chambers and to selectively render any chamber inactive, inlet means for each chamber, means to supply refrigerant directly to the inlet means of the primary chamber when the primary chamber is active and directly without entering an 'inactive chamber to the inlet means of the secondary chamber when the primary chamber is inactive, and means to supply refrigerant from the primary chamber to the inlet means of the secondary chamber when both chambers are active. 4 In refrigerating apparatus, an evaporator having a primary chamber and a secondary chamber, evacuating means to reduce the pressure in each chamber, means to receive the discharge of the evacuating means, means to seand thereby subject a chamber having an inactive evacuating means to the pressure in the receiving means, means to supply refrigerant directly to the primary chamber when the pressure in the primary chamber is below the pressure in the receiving means and directly without entering an inactive chamber to the secondary chamber when the pressure in the primary chamber is'at least equal to the pressure in the receiving means, and means to supply a refrigerant from the primary chamber to the secondary chamber whenthe pressure in each said chamber is below the pressure in the receiving means. 5. In refrigerating apparatus, an evaporator, having a primary chamber and a secondary chamber, evacuating means to reduce the pressure in each chamber, means to receive the discharge of the evacuating means, means to'selec-- tively render the evacuating means inactive and thereby subject a chamber having an inactive evacuating means to the pressure in the receiving means, means to supply refrigerant directly to the primary chamber when the pressure in the primary chamber is below the pressure in the receiving means and directly without entering an inactive chamber to the secondary chamber when the pressure in the primary chamber is at least equal to the pressure in the receiving. means, means to supply a refrigerant from the primary chamber to the secondary chamber when the pressure in each said chamber is below the pressure in the receiving means, and means to remove refrigerant from the evaporator through tive chamber to the secondary chamber when the primary chamber is inactive, means to supply refrigerant from the primary chamber to the secondary chamber when both chambers are active, and outlet means associated with the chamhers to remove refrigerant in the evaporator from the secondary chamber when the secondary lectively render the evacuating means inactive chamber is active and from the primary chamber when the secondary chamber'is'inactive. 7. In refrigerating apparatus comprising an evaporator having a plurality ofcvaporator chambers, an evacuator for each said ,chamber to reduce the pressure in and to selectively render any chamber. active, a. condenser to receive the discharge of said evacuators, a refrigerant inlet for each chamber, an evaporator discharge outlet connected to each chamber, means to discharge refrigerant from an active chamber to the inlet of another active chamber,'and a control chamber constantly subjected to the condenser pressure to prevent the entrance of refrigerant to the inlets of inactive chambers. 8. In refrigerating apparatus, a staged evaporator having a primary chamber and a secondary chamber, evacuating means to reduce the pressure in the chambers and to selectively render any chamber inactive, means to receive the discharge from the evacuating means, means to supply refrigerant to the evaporator, means to spray refrigerant into the chambers, means to direct refrigerant from the. primary chamber to the spray means for the secondary chamber when both chambers are active, and a non-evaporating chamber .in the evaporator in constant communication with the spraying means and the discharge receiving means to control the flow of refrigerant and prevent the entry of any refrigerant to any inactive chamber when any chamber is active. 9. In refrigerating apparatus, a multi-stage evaporator having a plurality of evaporating chambers in series arrangement, each stage having at least one chamber, evacuators for reducin the pressure in and selectively rendering any evaporating chamber active, inlet means for each chamber tointroduoe refrigerant to be evaporated, by-pass means associated with each evaporator chamber constantly subjected to the discharge pressure of the evacuators to prevent the entry of refrigerant to any inactive chamber chambers. through its inlet means in response to the increase of pressure in an inactive chamber, and seals between the chambers formed by refrigerant in the last said means. 10. In refrigerating apparatus, an evaporator having a plurality of refrigerating chambers, means to reduce the pressure in each chamber and to selectively render any chamber active, means to receive the discharge of the last said means, inlet means for each chamber to supply refrigerant to said chambers, a control chamber subject to the pressure of the discharge receiving means associated with the inlet means to admit refrigerant only to the inlet means of active chambers, means to direct refrigerant discharged from an active chamber around the control chamber to the inlet means of another active chamber and enable refrigerant to pass through active chambers serially, an evaporator outlet for each chamber, and a second control chamber associated with the refrigerant outlet of a refrigerating chamber arranged to stop the flow of refrigerant through the outlet when the refrigerating chamber is inactive and another refrigerating chamber is active and when refrigerant is flowing through a series of active refrigerating ALFRED D. KARR.

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