Patent Publication Number: US-7219503-B2

Title: Quick-change coalescent oil separator

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to compression refrigeration systems including a coalescent oil separator. More specifically, one form of the present invention relates to a coalescent oil separator system that enables servicing of the separator without having to shut down or remove the refrigerant from the refrigeration system. 
   BACKGROUND OF THE INVENTION 
   Typically, refrigeration systems include a compressor for compressing a refrigerant gas, a condenser to cool and condense the compressed refrigerant gas to a refrigerant liquid and an evaporator for absorbing heat from a fluid to provide a chilled liquid for refrigeration of a desired area. Most compressors utilize an oil to lubricate the mechanical components and enhance the sealing interface between the components that are performing the necessary work on the refrigerant gas to raise its pressure. A portion of the oil used in the compressor for lubrication often becomes entrained with the refrigerant gas and is discharged from the compressor. This mixture of the oil and refrigerant gas may be carried from the compressor to the other components including the condenser and evaporator. 
   Oil, however, is not considered a refrigerant and the efficiency of the refrigeration system is reduced if the oil remains mixed with refrigerant gas as it moves through the system. Furthermore, if the oil travels from the compressor to the other components of the refrigerant system and is not returned to the compressor more oil will need to be added to the compressor in order to maintain the compressor performance; for the lack of oil may cause the compressor to fail. 
   Although there are many prior systems for separating oil from the refrigerant gas, there remains a need for an improved oil separation system for refrigeration systems. The present inventions satisfy this and other needs in a novel and unobvious way. 
   SUMMARY OF THE INVENTION 
   One form of the present invention contemplates an apparatus compromising: a refrigeration system including an evaporator, a condenser and a compressor, the compressor including a compressor discharge through which flows a mixture including refrigerant gas and an oil; a coalescent oil separator having an inlet in fluid communication with the compressor discharge and an outlet in fluid communication with the condenser, the coalescent oil separator separating at least a portion of the oil from the refrigerant gas; and a by-pass check valve disposed between the inlet and the outlet, the by-pass check valve is normally closed but opens when the fluid pressure controlling its operation exceeds a threshold value thereby allowing the refrigerant gas and oil to bypass the coalescent oil separator and flow to the condenser. 
   Another form of the present invention contemplates an apparatus comprising: at least one refrigeration system including an evaporator, a condenser and a compressor, the compressor has a compressor discharge through which flows a fluid including a refrigerant gas and an oil; a coalescent oil separator having an inlet in fluid communication with the compressor discharge and an outlet in fluid communication with the condenser, the coalescent oil separator separating at least a portion of the oil from the refrigerant gas; a first valve disposed between the compressor discharge and the inlet and being operable to block the flow of the fluid to the coalescent oil separator; a second valve disposed between the outlet and the condenser and being operable to block fluid flow from the outlet; and a by-pass check valve disposed between the first valve and the second valve, the by-pass check valve is normally closed but opens when the pressure acting on the by-pass valve exceeds a threshold value to allow the fluid to flow through a passageway around the coalescent oil separator and to the condenser. 
   In yet another form the present invention contemplates a method for servicing a coalescent oil separator utilized to separate oil from a refrigerant gas and oil mixture that is discharged from a compressor within a refrigeration system, comprising: diverting the refrigerant gas and oil mixture from the compressor around the coalescent oil separator to a condenser of the refrigeration system; blocking the flow of the refrigerant gas and oil from the compressor to an inlet of the coalescent oil separator; blocking the flow from a coalescent oil separator outlet, the coalescent oil separator outlet is normally in fluid communication with the condenser; and servicing the coalescent oil separator during the diverting. 
   These and other objects of the present invention will become more apparent from the following description of the illustrative embodiment. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of one embodiment of a coalescent oil separator system coupled in fluid communication with a compression cycle refrigeration system. 
       FIG. 2  is a schematic view of the system of  FIG. 1  wherein the bypass check vale is in an open state. 
       FIG. 3  is an enlarged partially exploded view of the coalescent oil separator system of  FIG. 2 . 
   

   DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS 
   For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention is illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
   With reference to  FIG. 1 , is illustrated one form of a supermarket rack refrigeration system  10 . The supermarket rack refrigeration system  10  includes a plurality of compression cycle refrigeration systems  11 . The present application will utilize the supermarket rack refrigeration system as an illustrative embodiment, however the present application is not intended to be limited to this specific refrigeration system application and/or to including a plurality of refrigeration systems  11 . The present application contemplates that the number of refrigeration systems can be one or more. 
   Each of the compression cycle refrigeration systems  11  includes three primary components, a compressor  12 , a condenser  13  and an evaporator  14 . The components are coupled together in a closed loop system through which flows a refrigerant gas. The compressor  12  compresses the refrigerant gas from a relatively lower pressure gaseous state to a relatively higher pressure gaseous state. The refrigerant gas exits the compressor  12  through the compressor discharge  15  and ultimately flows to the condenser  13 . At the condenser  13  energy is removed from the refrigerant gas to facilitate the condensation of the refrigerant gas into a liquefied refrigerant. The liquefied refrigerant flows through an expansion device (not illustrated) into the evaporator  14  where the liquid refrigerant absorbs energy and evaporates; thereby functioning to cool an area associated with the evaporator  14 . The liquid refrigerant has returned to the gaseous state and now flows from the evaporator  14  to the compressor  12  where the compressor is operable to increase the pressure to the relatively higher pressure gaseous state. Further information regarding the general operation of compression cycle refrigeration systems is not set forth herein as the information is believed generally known to those of ordinary skill in the art. 
   The compressor  12  includes a mechanical structure that is moved to do work on the relatively lower pressure refrigerant gas to increase the pressure to a relatively higher pressure refrigerant gas. In one form the moveable mechanical structure may include a reciprocating piston that moves relative to a cylinder bore. An oil is used between the piston and the cylinder bore to reduce the friction and enhance the seal between the respective components. The term oil as utilized herein is intended to broadly define a lubricant that may be synthetic based, petroleum based, of a single or multi-viscosity and may include a variety of additives. During the normal operation of the compressor  12 , some of the oil is mixed with the refrigerant gas and is discharged through the compressor discharge  15 . The refrigerant gas and oil mixture discharged from the compressor  12  may also include other contaminants. 
   In one form of the present invention, the fluid discharged from the compressor  12  includes the relatively higher pressure refrigerant gas and a quantity of the oil entrained therein. It should be understood herein that the fluid discharged from the compressor does not have to have a consistent amount of oil or other contaminants entrained therein The fluid exits the compressor discharge  15  and is passed through a fluid flow passageway  16  to an inlet  25  of a coalescent oil separator  17  and then to the coalescent oil separator  17 . Within the coalescent oil separator  17  the oil and/or other contaminants and/or other materials are substantially removed from the fluid mixture to yield a refrigerant gas that passes out of the coalescent oil separator outlet  20 . Upon completion of the separation process within the coalescent oil separator  17  the refrigerant gas flows out of the coalescent oil separator outlet  20  and through a passageway  27  to the condenser  13 . In one form the separated oil is collected in an oil return housing  21  and subsequently returned to compressor  12  through an oil return line  22 . 
   With reference to the embodiment of refrigeration system  10  depicted in  FIG. 1 , there is included a plurality of refrigeration systems  11  that each have their compressor discharges  15  connected in fluid communication with the passageway  16 . The fluid exiting each of the compressor discharges  15  passes from the passageway  16  into the coalescent oil separator  17 , and after being processed in the coalescent oil separator  17  is returned to the condensers  13  through passageway  27 . However, as previously discussed the present application contemplates that the system may include one or more refrigeration systems  11  and there is no intention herein to limit the present application to a system including a plurality of refrigeration systems, unless specifically provided to the contrary. 
   Significant details regarding coalescent oil separators are believed generally known to one of ordinary skill in the art and therefore will not be recited in this document. The coalescent oil separator  17  includes a removable filter  23  that is located within a fluid tight mechanical housing  24  has a removable cover plate  40 . In one form the cover plate  40  is secured to the mechanical housing  24  by a plurality of fasteners  41 . The removable filter  23  includes a fine glass matrix type material capable of filtering out, but not limited to, liquid droplets, small particles and material/contaminants from the refrigerant gas within the fluid flow. More preferably the filter  23  removes the oil mixed with the refrigerant gas. In one preferred form the filter  23  is formed of a borosilicate material that can filter out liquid droplets, small particles and/or material/contaminants from the refrigerant gas down to about 0.3 microns. Coalescent oil separator filters due to their extremely fine particle filtering capability are prone to be plugged and/or clogged by the material separated by the filter from the fluid being processed. The plugging and/or clogging of the filter  23  causes an increase in the pressure drop across the filter. 
   A one way by-pass check valve  32  is disposed in fluid communication with the compressor discharge fluid in the passageway  16 . The compressor discharge fluid acts on the surface  37  and when the pressure exceeds a predetermined threshold the check valve  32  opens to allow the compressor discharge fluid to flow around the coalescent oil separator  17 . The check valve  32  is normally closed with the valve body  35  disposed in sealing contact with the valve seat  36 . With the check valve  32  in the normally closed position the compressor discharge fluid passes into the coalescent oil separator  17 . As the filter  23  becomes blocked and/or clogged the pressure acting on the surface  37  increases. When the pressure acting on the surface  37  exceeds a threshold value the valve body  35  moves from the valve seat  36  and fluid flows through the valve  32 . The check valve  32  in one form is a spring actuated valve. The check valve  32  is calibrated to open at threshold values that have been selected for the individual system. In one form of the present invention the check valve  32  opens at about 10 PSIG. However, it is contemplated herein that the check valve  32  can open at a variety of other pressures as required by the system design. 
   With reference to  FIG. 2 , there is illustrated the system  10  with the check valve  32  in an open state. In the open state the compressor discharge fluid bypasses coalescent oil separator  17 . The check valve  32  will open upon the pressure acting on the surface  37  being above a threshold value so that the valve body  35  moves from the seat  36 . In one situation the filter  23  becomes clogged or plugged to an extent that the pressure in passageway  16  acting upon surface  37  exceeds a predetermined threshold value and the valve opens. 
   With reference to  FIGS. 1–3 , there is illustrated that in one form of the present invention there is included a valve  30  prior to the coalescent oil separator inlet  25  and a valve  31  after the coalescent oil separator outlet  20 . The present application also contemplates a system without either of these valves. The valve  30  is operable to control the flow of compressor discharge fluid to the coalescent oil separator inlet  25 . Upon the valve  30  being in the open state the compressor discharge fluid flow to the coalescent oil separator inlet  25  is not blocked, and when the valve  30  is in a closed state the fluid flow to the coalescent oil separator inlet  25  is blocked. Valve  31  is located between the coalescent oil separator outlet  20  and the condenser  13 . Upon the valve  31  being in a open state the fluid flow from the coalescent oil separator outlet inlet  20  is not blocked, and when the valve  31  is in a closed state the fluid flow from the coalescent oil separator outlet  20  is blocked. In one form of the present invention the valves  30  and  31  are full flow ball type valves. However, other types of valves are contemplated herein. The check valve  32  is located between the valves  30  and  31  in one form of the present invention the valves  30  and  31  are in a normally open state. 
   In order to service the coalescent oil separator  17  without having to shut down the refrigeration systems  11  or reclaim the refrigerant the valves  30  and  31  are closed. The closing of the valves  30  and  31  isolates the coalescent oil separator  17  from the rest of the refrigerant system  10 , and causes the check valve  32  to open and diverts the compressor discharge fluid around the coalescent oil separator  17 . Since the systems have not been shut down or purged of the refrigerant material the pressurized refrigerant gas within the system bypasses the oil coalescent separator  17  and proceeds to the respective condensers  13 . 
   With reference to  FIGS. 2 and 3 , there is illustrated the one way check valve  32  in an open state to allow the bypass of compressor discharge fluid around the coalescent oil separator  17 . The valves  30  and  31  have both been closed to isolate the coalescent oil separator  17  from the rest of the system. However, it should be understood herein that the closing one or both of the valves  30  and  31  may result in the fluid pressure acting on surface  37  rising to a level sufficient to cause check valve  32  to open. However, it is also possible that valves  30  and  31  may be maintained in a fully open state and that the filter  23  within the oil coalescent separator  17  becomes plugged to an extent that the drop in pressure across the filter  23  causes pressure in line  16  to exceed the threshold pressure and valve  32  is opened. 
   In the system depicted in  FIG. 3 , the valves  30  and  31  have been closed to block fluid flow to or from the coalescent oil separator  17  and the one way check valve  32  has opened due to the fluid pressure acting thereon. The refrigeration systems  11  have not been shut down nor have the systems  11  had their refrigerant removed. However, the present application also contemplates that one or more of the refrigeration systems may not be running. Therefore it should be understood that the servicing and/or changing of the filter  23  and/or the coalescent oil separator  17  is occurring with the system in a normal operating condition. 
   In one form of the present invention the bottom plate  40  is removed from the housing  23  by the removal of the plurality of fasteners  41 . With the bottom plate  40  removed the coalescent oil separator filter  23  is assessable and is removed by removing a nut  42  from the threaded rod  43 . Thereafter the coalescent oil separator filter  23  can be removed from the housing  24  and serviced or replaced with a fresh filter. Upon completion of the servicing of the filter  23  the nut  42  is reinstalled and the bottom plate  40  is secured with fasteners  41  to the housing  24 . Valves  30  and  31  are then opened to allow the passage of fluid into and out of the coalescent oil separator  17 . In the event that one of the valves  30  and  31  is left inadvertently closed, the one way check valve  32  will open and allow the fluid to bypass around the coalescent oil separator  17 . Further, the same general procedure may be used to repair or replace the coalescent oil separator  17 . 
   The passageways  27  and  16  and the oil return line may be formed of a variety of piping and tubing. Further, the routing of the passageways is illustrative and other configurations are contemplated herein. 
   While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.