Abstract:
A filter in some embodiments of the invention includes: a housing defining an interior chamber substantially sealed from outside of the housing; a valve located in the chamber biased to a first position where the valve maintains a seal between the interior chamber and outside of the housing; and an anchor fixed to the housing defining a surface for a spring to urge against and bias the valve to the first position and be compressed against when a receiver enters into the housing a moves the valve to a second position, the anchor defining, at least in part, flow paths wherein a pressurized fluid within the housing can communicate with an interior of the receiver to equalize a pressure within the chamber and the interior of the receiver; and a nipple attached to the housing having an interior passageway configured to permit the receiver to pass through in a substantially sealed manner. A method of attaching a filter to a filter receiver is also provided.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an apparatus for processing air-conditioning refrigerant. More particularly, the present invention relates to a method and apparatus that identifies whether a filter dryer for refrigerant processing machine has been replaced. 
     BACKGROUND OF THE INVENTION 
     Filter dryers in refrigerant recovery units are used to trap acid, moisture, or particulates as the refrigerant passes through the filter dryers. These filter dryers, typically, have a maximum capacity to trap these contaminants. In order for the refrigerant recovery unit to function properly, these filter dryers need to be replaced periodically to ensure the refrigerant is cleaned upon the recovery/recycle process. Otherwise, continued use of the saturated filter dryers can be damaging to the air conditioning system. 
     Currently, a user is prompted to change the filter dryer when a predetermined amount of refrigerant has passed through the filter dryer, such as one-hundred and fifty pounds. However, the user may simply ignore the notification by pushing a button indicating that he has changed the filter dryer and continues to use the expired filter dryer for the recovery/recycle process. Furthermore, the counter will reset to zero and the notification will not be activated until another one-hundred and fifty pounds of refrigerant has passed through the filter dryer. Thus, the refrigerant passing through the filter dryer will not be cleaned properly upon the recovery/recycle process. 
     Accordingly, it is desirable to provide a method and apparatus to ensure that a user performs filter dryer maintenance for a refrigerant recovery unit when the filter dryer needs to be replaced. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by the present invention, wherein in some embodiments provides a method and apparatus to ensure that a user performs filter dryer maintenance for a refrigerant recovery unit when the filter dryer needs to be replaced. 
     In accordance with one embodiment of the present invention, a filter is provided. In some embodiments of the invention, the filter includes a housing defining an interior chamber substantially sealed from outside of the housing, a valve located in the chamber biased to a first position where the valve maintains a seal between the interior chamber and outside of the housing, an anchor fixed to the housing defining a surface for a spring to urge against and bias the valve to the first position and be compressed when a receiver enters into the housing and moves the valve to a second position, the anchor defining, at least in part, flow paths wherein a pressurized fluid within the housing can communicate with an interior of the receiver to equalize a pressure within the chamber and the interior of the receiver and a nipple attached to the housing having an interior passageway configured to permit the receiver to pass through in a substantially sealed manner. 
     In accordance with another embodiment of the present invention, a method of attaching a filter to a filter receiver is provided. In some embodiments of the invention, the method includes opening a valve with a receiver, equalizing a pressure between an interior of the filter and an interior of the receiver, sensing the equalized pressure, transmitting a signal associated with the equalized pressure to a controller, and permitting function of a fluid processor if the signal is indicative of an acceptable pressure. 
     In accordance with yet another embodiment of the present invention, a filter system is provided. In accordance with some embodiments of the invention, the filter includes means for containing a pressure within an interior chamber, means for valving the interior chamber biased to a first position the valving means maintains a seal between the interior chamber and outside of the chamber, means for anchoring the valving means, means for biasing the valving means to the first position and be moved to a second position when a receiver enters into the chamber, the anchoring means defining, at least in part, flow paths wherein a pressurized fluid within the chamber can communicate with an interior of the receiver to equalize a pressure within the chamber and the interior of the receiver, and means for connecting the filter to a fluid processor. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a connector associated with a refrigerant recovery unit and a filter with a portion of the filter&#39;s housing cut away to expose interior portions of the filter. 
         FIG. 2  is a side view of a filter receiver engaged with a filter dryer having a portion of the housing on the filter dryer removed in order to illustrate interior portions of the filter dryer. 
         FIG. 3  is a schematic diagram of a portion of a refrigerant recovery device including a pressure sensor, a controller, and a lock out device. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention as shown in  FIG. 1  is a filter dryer  10  for a refrigerant recovery device. The filter dryer  10  includes a filter housing  12 . The filter housing  12  (as shown in  FIGS. 1 and 2 ) has been partially cut away so that the interior parts of the filter dryer  10  can be illustrated. The filter dryer  10  includes filter media which is configured to filter out particulate matter and also moisture from a refrigerant being processed by a refrigerant recovery device. 
     Because as moisture is removed, in some embodiments of the invention, the filter referred is sometimes referred to as a filter dryer rather than solely as a filter. In other embodiments and accordance of the invention, drying function may not necessarily be performed. For the purpose of this document, the term filter and the term filter dryer are intended to the interchangeable and not necessarily to limiting the function of a device in accordance with the invention. 
     The filter  10  (as shown in  FIGS. 1 and 2 ) is a partial view of the filter  10 . The filter  10  includes an interior portion  13 . The interior portion  13  is contained within the filter housing  12 . Located on the filter housing  12  is a nipple  14 . The nipple  14  has exterior threads  16 . The nipple  14  defines an interior passageway  17 . 
     The passageway  17  is open at one end of the nipple  14  and extends longitudinally through the nipple  14  and is terminated by a valve  18 . The valve  18  when in a closed position, prevents fluid communication between the interior  13  of the filter  10  and the passageway  17 . The valve  18  has a valve shaft  20 . In some embodiments of the invention, the valve  18  and the valve shaft  20  are one unitized part. In other embodiments of the invention, the valve  18  and the valve shaft  20  may be comprised of two different parts. In some embodiments of the invention, the valve  18  is stainless steel. 
     A plate  22  is located in the interior  13  of the filter  10 . The plate  22  is fixed or attached to the housing  12 . The plate  22  includes holes  24  which provide passageways for fluid to flow from one side of the plate  22  to the other side of the plate  22 . The plate  22  provides an anchor for the spring  26  to urge against. 
     The spring  26 , in some embodiments of the invention, is a coil spring located around the valve shaft  20 . The spring  26  urges against the plate  22  on one end and against the valve  18  at the other end. The spring  26  biases the valve  18  to a closed position. The valve  18  creates a seal between the interior portion  13  of the filter  10  and the interior passageway  17  through the nipple  14 . In some embodiments of the invention, the valve  18  may include an O ring, gasket, resilient material or other similar structure to facilitate sealing the passageway  17  from the interior  13  of the filter  10 . 
     The left side of  FIG. 1  illustrates a filter receiver  28 . The filter receiver  28  includes a tube portion  29 . In some embodiments of the invention, the tube  29  may be copper. In other embodiments of the invention, other metals or materials may be used. The tube  29  includes a tube end  30 . The tube  29  has an interior space  31  running the length of the tube  29 . 
     The tube end  30  has an open end  32  providing fluid communication between interior  31  of the tube  29  and the ambient conditions outside of the tube  29 . The open end  32  also includes side holes  34  which also provide fluid communication between the ambient conditions outside the tube  29  and the interior  31  of the tube  29 . Thus, fluid communication can occur between the interior  31  of the tube  29  either through the open end  32  or the side holes  34 . 
     Mounted on the tube  29  is a swivel nut  36 . The swivel nut  36 , in some embodiments of the invention, contains internal threads  38 . The interior threads  38  of the swivel nut  36  are configured to attach to the exterior threads  16  of the nipple  14  as shown and described in more detailed below with respect to  FIG. 2 . 
     A sensor  40  is in communication with the interior  31  of the tube  29 . The sensor  40  may be located anywhere along the tube  29 . The sensor  40  is configured to detect pressure of fluid within the interior portion  31  of the tube  29 . 
     Turning now to  FIG. 2 ,  FIG. 2  illustrates the filter dryer  10  mechanically connected to the filter receiver  28 . The interior  13  of the filter  10  is fluidly connected to the interior  13  of the tube  29 . 
     As shown in  FIG. 2 , the tube end  30  has passed through the interior passageway  17  contained in the nipple  14  so that the tube end  30  has pressed against the valve  18  and moved the valve  18  against the force of the spring  26 . The valve  18  has been lifted from its seated sealing position. The tube end  30  is now physically located in the interior  13  of the filter  10 . Fluid communication is now accomplished between the interior  13  of the filter  10  and the interior  31  of the tube  29  via the passageways in the plate  24  and the side holes  34  and the open end  32 . 
     In some embodiments of the invention, the open end  32  of the tube end  30  may be somewhat hindered or blocked by the valve  18 . Thus, the side holes  34  provide unimpeded fluid communication between the interior  13  of the filter  10  and the interior  31  of the tube  29 . To secure the filter dryer  10  on to the filter receiver  28 , the swivel nut  36  may be turned to cause the internal threads  38  to engage and communicate with the external threads  16  on the nipple  14  to secure the filter  10  on to the filter receiver  28  (as shown  FIG. 2 ). 
     Tuning now to  FIG. 3 .  FIG. 3  illustrates a schematic diagram according to one embodiment of the invention. The schematic diagram shows a controller  42  that is operatively connected to the sensor  40 . As mentioned above, the sensor  40  is configured to sense a fluid pressure within the interior  31  of the tube  29 . The controller  42  is also operatively connected a lock out device  44 . In some embodiments of the invention, the lock out device  44  may actually be part of the controller  42 . 
     In some embodiments of the invention, the lock out device  44  may be software programmed onto the controller  42 . The controller  42  may be, in some embodiments of the invention, a microprocessor. 
     According to some embodiments of the invention, the controller  42  can be configured to monitor how much refrigerant has been processed by a refrigerant recover unit. When the refrigerant recovery unit has processed a certain amount of refrigerant (for example, in some embodiments a 150 pounds of refrigerant) the controller  42  may be programmed to engage the lock out device  44  so the refrigerant recovery device will not function until the filter  10  has been replaced. Such a lock out feature ensures that a filter  10  is replaced at regular intervals. 
     In some embodiments of the invention, the filter interior  13  is given a predetermined amount of fluid pressure. In some embodiments of the invention, the fluid pressure is a positive pressure, or in other words exceeds atmospheric or ambient conditions outside the filter. 
     When in some embodiments of the invention, a preset amount of fluid, has been processed, the controller  42  will engage the lock out procedure  44  which stops or reduces the operation of the refrigerant recovery device until a new filter  10  has been replaced onto the filter receiver  28 . 
     In order to change the filter  10  from the filter receiver  28 , the interior  31  of the tube  29  is evacuated to remove the refrigerant. The filter  10  then is removed by loosening the swivel nut  36  and removing the tube end  30  from the interior passageway  17  of the nipple  14 . At such time, the pressure within the interior  31  of the tube  29  will equalize with the ambient air conditions outside of the interior  31  of the tube  29  because free fluid communication can occur between the interior  31  of the tube  29  and the ambient conditions outside of the filter receiver  28 . 
     According to some embodiments of the invention, a signal associated with the pressure of the evacuated interior  31  of the tube  29  is supplied to the controller  42  as sensed by the sensor  40 . When the filter  10  is removed, the equalization of the pressure inside the interior  31  of the tube  29  with the ambient air is also sensed by the sensor  40  and reported to the controller  42 . 
     Finally, once the new filter  10  has been installed onto the filter receiver  28  and the fluid pressure within the interior  13  of the filter  10  equalizes with the interior  31  of the tube  29 . This equalized pressure as sensed by the sensor  40  is then reported to the controller  42 . Different pressures or pressure ranges associated with each of the different steps: evacuating the interior of the tube  31 ; equalizing the interior  31  of the tube  29  with the ambient air conditions and then equalizing the interior  31  of the tube  29  with the interior  13  of the filter  10  are reported by the sensor  40  to the controller  42 . 
     Some embodiments in accordance with the invention do not monitor the pressure at all of the aforementioned times but rather, the pressure sensor  40  reports the pressure with the interior  31  of the tube  29  once the new filter  10  has been placed on the filter receiver  28 . Once this pressure is reported to the controller  42  and it is within a predetermined range, the controller  42  disengages the lock out feature  44  and permits operation of the fluid processing unit. 
     In some embodiments of the invention, existing recovery units can be modified to have new software programmed onto the controller  42  and the filtering receiver  28  can be modified in accordance of the invention. In other embodiments of the invention, current designs of recovery recycling recharging units can be modified so that future built units will have the controller programmed to control software that will operate the lock out feature  44  as described herein. In addition, the recovery unit will be equipped with a filter receiver  28  with filter  10  in accordance with the invention. 
     An example of a recovery recycle recharging unit that can be modified to have a controller, a sensor, and lock out feature along with a filter receiver and filter dryer in accordance with the invention, is the recovery recycle recharging unit that is currently sold by the SPX Corporation under the tradename ROBINAIR and identified as the model 34788. After reviewing the disclosure contained herein, one skilled in the art could modify such a refrigerant recovery unit such as the ROBINAIR model 34788 or other similar refrigerant recovery units to be in accordance of the invention. 
     Another refrigerant recovery unit that can be modified to be in accordance with the invention is a recovery unit as described in U.S. patent application Ser. No. 11/709,825; titled, Component Identification System and Method; filed Feb. 23, 2007; with Raheel Ashraf Chaudhry listed as the inventor, the disclosure of which is incorporated herein by reference in its entirety. 
     Another refrigerant recovery unit that may be modified to be in accordance with the invention is a recovery unit as described in U.S. patent application Ser. No. 11/477,585; titled, Method and Apparatus For Refrigerant Recovery Unit Filter Dryer Maintenance; filed Jun. 30, 2006; having Travis Bakker and Gary Murray listed as the inventors, the disclosure of which is incorporated herein by reference in its entirety. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.