Abstract:
A hand operated pump and filter assembly for transferring low viscosity fluids, such as hydraulic oil, from a supply container to a machine requiring the fluid, and for filtering the fluid. The pump is a combination vacuum and displacement pump. The pump has a barrel with a cylindrical central passageway therein. A piston is positioned within the central passageway and is connected to the lower end of a piston rod. The upper end of the piston rod is attached to a handle for effecting upward and downward movement of the piston. The piston has fluid passageways extending therethrough and valve means associated with the fluid passageways to prevent fluid from flowing through the passageways during the piston upstroke but allowing fluid to flow through the passageways during the piston downstroke. The inlet end of the pump barrel has a valve subassembly means which seals communication between the central passageway thereof and a fluid supply container during the piston downstroke but opens communication during the piston upstroke. An adapter is provided for locking the pump barrel to the outlet of a fluid supply container. The outlet end of the pump barrel communicates with a filter via a conduit. The filter is preferably a ten micron filter for removing very fine impurities from the fluid being pumped. The outlet of the filter communicates with the machine to which the fluid is being transferred via a flexible conduit.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a hand operated pump and filter assembly for transferring and filtering low viscosity fluids, such as hydraulic oils, transmission fluids, some motor oils, etc. 
     With modern hydraulic machinery the components that pump and control the machine have critical clearances of down to about 0.0003 inch. Contamination of the hydraulic oil causes accelerated wear in the high performance components of such systems. 
     It is known in the bearing industry that bearing life is extended when the hydraulic oil is properly filtered. Hydraulic component manufacturers will not always honor component warranties if the oil does not meet ISO 4406 specifications. 
     A number of hydraulic oil transfer pumps have been used, but none have addressed the problem of pushing the oil through a fine (ten micron) filter to keep contamination out of high performance components with clearances of about 0.0003 inch. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide a hand operated pump for transferring low viscosity fluids from supply containers to a fluid reception point. 
     It is a further object of this invention to provide a hand operated pump and filter assembly for transferring low viscosity fluids from supply containers to a fluid reception point. 
     It is a still further object of this invention to provide a hand operated pump and filter assembly for transferring hydraulic oil from a supply container through a ten micron or less filter to machinery having components which require close tolerances. 
     These and other objects are achieved by providing a manually operated Dump that acts as a combination vacuum and displacement pump. 
     The pump of the invention has a barrel with inner and outer cylindrical walls, the inner cylindrical wall forming a central passageway extending between an inlet end and an outlet end. 
     A cylindrical piston rod is positioned with its inner end being located within the e central passageway of the e barrel and its outer end outside the central passageway of the barrel, the piston rod and barrel having a common longitudinal axis. The outer cylindrical wall of the barrel has a longitudinally extending vent groove machined therein to allow air to enter a fluid supply container as fluid is being pumped out of it. 
     The outer end of the piston rod is attached to a handle for manually raising and lowering the piston rod during the upstroke and downstroke, respectively. 
     A piston is attached to the inner end of the piston rod. The piston has at least one fluid passageway extending therethrough, the passageway having an associated valve means for closing the passageway during an upward stroke of the piston rod and opening the passageway during a downward stroke of the piston rod. 
     The inlet end of the barrel has valve subassembly means for opening communication between the exterior of the barrel and its central passageway during an upstroke and closing communication during a downstroke. 
     A lock adapter for attaching the pump to a fluid oil supply container is provided. The adapter is slidably attached to the outer cylindrical wall of the pump barrel and is threaded to lockingly engage the threads of the outlet of a supply container. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view, partially in cross-section, of the pump and filter assembly of this invention; 
     FIG. 2 is an enlarged, cross-sectional view of the piston subassembly of this invention; 
     FIG. 3 is a top view of the pump piston; 
     FIG. 4 is a bottom view of the inlet subassembly; 
     FIG. 5 is a cross-sectional view of the outlet subassembly; 
     FIG. 6 is a cross-sectional view of the fluid supply container lock adapter; and 
     FIG. 7 is a view, partially in cross-section, of the fluid supply lock adapter located on the pump barrel. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The pump  10  of the invention is comprised of a barrel  12  having inner and outer cylindrical walls, the space within the inner cylindrical wall forming a central passageway  13   a . A cylindrical piston rod  14  has its inner end located within the central passageway  13   a  of barrel  12  and its outer end located outside the central passageway of barrel  12 . An annular oil passageway  13   b  is formed in the space between the inner cylindrical wall of barrel  12  and the outer cylindrical wall of piston rod  14 . Barrel  12  and piston rod  14  have a common longitudinal axis. 
     An oil inlet subassembly  20  having first and second cylindrical body portions  21  and  22  is removably attached to the lower end of barrel  12 , such as by press fitting cylindrical body portion  22  against the inner cylindrical wall of the lower end of barrel  12 . First and second oil inlet passageways  23  and  24 , respectively, are centrally located within first and second cylindrical body portions  21  and  22 , respectively. A narrowed passageway formed by annular shoulder  25  communicates first passageway  23  with second passageway  24 , with shoulder  25  forming a seat for ball  26  located within second passageway  24 . Thus, oil inlet subassembly  20  acts as a check valve during operation. 
     Several semicircular openings  27 , preferably three, are cut out of the first (lower) end of first cylindrical body portion  21  of inlet subassembly  20 , only one of which openings  27  is shown in FIG.  1 . Semicircular openings  27  permit oil to enter first passageway  23  even if the lower end of oil inlet subassembly  20  is otherwise touching and in sealing contact with the bottom of an oil supply container. 
     Stop pin  28  prevents ball  26  from entering the lower end of barrel  12 . 
     Outlet subassembly body  30  is generally cylindrical and has an upper body portion  32   a , a mid-body portion  32   b , and a lower body portion  32   c . Upper body portion  32   a  and lower body portion  32   c  each have a central bore running therethrough. Mid-body portion  32   b  has a central fluid receiving cavity  37  therein communicating with the central bore of lower body portion  32   c  for receiving fluid from annular fluid passageway  13   b.    
     Outlet subassembly  30  is removably attached to the upper end of barrel  12 , preferably by having the diameter of the outer surface of barrel  12  and the inner surface of the central bore of lower body portion  32   c  being close enough to each other to provide a for a press fit therebetween. However, outlet subassembly  30  can be removably attached to the upper end of barrel  12  by other means, such as mating threads located on the outer surface of barrel  12  and on the inner surface of the central bore of lower body portion  32   c.    
     An annular seal groove  33  is located at the upper end of the inner surface of the central bore of the upper body portion  32   a . Seal groove  33  is adapted to receive a ring type seal member (not shown) to prevent oil from leaking between piston rod  14  and the adjacent inner surface of the bore of upper body portion  32   a.    
     Two piston rod annular centering grooves  34  are located below annular seal groove  33 . Centering grooves  34  fill with oil during use of pump  10 , and turbulence caused by pumping acts to center the upper end of piston rod  14 , the lower end of piston rod  14  being centered by piston  42 . Also, the land area  35  between centering grooves  34  is a bearing surface lubricated by the fluid being transferred by pump  10 . 
     An oil exit port  36  is located in the mid-body portion  32   b  of outlet subassembly  30 , as shown. Oil exit port  36  communicates oil receiving cavity  37  with the exterior of the mid-body portion  32   b  of exit subassembly  30 . 
     A threaded inlet fitting or nipple  39  is attached to oil exit port  36 , such as by mating threads located on the exterior of nipple  39  and the interior of exit port  36 . 
     Piston rod  14  is formed of solid rod stock and has a first and second end. The first, inner end is located within the central passageway  13   a  of barrel  12  and terminates at a tip  15 . Tip  15  has a smaller diameter than the main body portion of piston rod  14 . The second, outer end of piston rod  14  is located outside the central passageway  13   a  of barrel  12 . 
     A handle  16  is attached to the outer end of piston rod  14  by any suitable means, such as a cap screw (not shown). Handle  16  is substantially perpendicular to piston rod  14  and has a length sufficient to allow space for both hands of the operator to grasp the handle  16  to manually operate the pump  10  with upstrokes (moving handle  16  away from the upper end of barrel  12 ) and downstrokes (pushing handle  16  toward the upper end of barrel  12 ). 
     A piston subassembly  40  is located on the tip  15  of piston rod  14 , as best seen in FIG.  2 . Piston subassembly  40  includes piston  42  which has planar upper and lower surfaces and a cylindrical wall extending between the upper and lower planar surfaces. The cylindrical wall of piston  42  is spaced from the inner wall of central passageway  13   a  a distance sufficient to allow for lubrication, as well known in the pumping art. 
     Piston  42  has a central opening therein into which outer end of tip  15  of piston rod  14  is inserted and attached to piston rod  14  by means of screw  44 , as shown. 
     Piston  42  preferably has three annular centering/sealing grooves  46  located in the cylindrical wall thereof. Centering/sealing grooves  46  keep piston  42  centered within central passageway  13   a  and provides a sealing affect during the upstroke by virtue of the turbulence caused by the pumping action acting upon the fluid located within grooves  46 . Grooves  46  also hold oil for lubricating the piston  42 . 
     Preferably three equally spaced apart fluid passageways  48  pass through piston  42  and communicate that portion of the central passageway  13   a  of barrel  12  located below the lower planar surface of piston  42  with the that portion of the central passageway  13   b  of barrel  12  located above the upper planar surface of piston  42 . 
     A flexible circular flapper valve  49  is located on the tip  15  of piston rod  14 , spaced apart and above the upper planar surface of piston  42 , as shown. The diameter of flapper valve  49  and its spacing from the upper planar surface of piston  42  is selected so that the flapper valve is brought into contact with the upper planar surface of piston  42  during an upstroke of piston rod  14  so that it substantially completely seals off passageways  48 . 
     An oil filter  50  is attached to the outer end of nipple  39 , such as by mating threads. Oil filter  50  is comprised of a cylindrical filter head  52  and a cylindrical filter container  54 . Filter container  54  screws into filter head  52  for easy removal. Filter container  54  contains filtration material which operates to remove impurities from oil in a manner well known in the art. Oil filter  50  is preferably capable of capturing contaminants having a particle size down to about ten microns or less. There are a number of suitable commercially available filter units, and the construction of the filter unit, per se, forms no part of the present invention. 
     A threaded outlet fitting or nipple  59  is screwed into filter head  52  opposite nipple  39 . A flexible discharge conduit or hose  60  is connected at its inner end to outlet nipple  59  of filter head  50 . Discharge hose  60  is preferably fitted to a quick disconnect nozzle  62  via an inlet fitting  64  to enable attachment to the hydraulic oil receiving port of the machine or device being serviced; however other types of nozzles may be used. A plastic plug  66  is used to plug the outlet end of nozzle  62  when the apparatus is not in use. 
     Hydraulic oil typically is sold in five gallon containers (buckets) equipped with a threaded flexible pour spout. Another feature of this invention is in providing a supply container lock adapter  70 , illustrated in FIGS. 6 and 7, which, after insertion of the lower portion of pump  10  into such a container, can be screwed onto the flexible pour spout of the container while the spout is retracted into the container to provide a rigid locking of the pump barrel  12  to the container. 
     Container lock adapter  70  has a tapered cylindrical body  71  having an upper end  72  and a lower end  73 . An annular square sealing ring groove  74  is located adjacent the upper end. Threads  75  are located on the outside of body  71  adjacent the upper end  72  thereof. 
     A central passageway  76  extends through body  71  from the upper end  72  to the lower end  73  thereof. Central passageway  76  is comprised of an upper passageway defined by cylindrical wall  77 , a central passageway defined by cylindrical wall  78 , and a lower passageway defined by cylindrical wall  79 . The diameter of the upper passageway is less than the diameter of the central passageway, and the diameter of the central passageway is less than the diameter of the lower passageway. The upper, middle, and lower passageways have a common longitudinal axis with each other and with barrel  12 . 
     An annular O-ring groove  80  is located in cylindrical wall  77 . Annular oil supply container spout threads  82  extend from cylindrical wall  78 . 
     Oil supply lock adapter  70  slides onto the outer cylindrical surface of barrel  12 , as shown in FIG. 7, with the outer surface of barrel  12  engaging upper cylindrical wall  77  as shown. In the position shown, adapter  70  is adapted to engage the flexible pour spout of a typical five gallon bucket of hydraulic oil after barrel  12  has been inserted into the bucket and the bottom of inlet subassembly  20  has touched the bottom of the bucket. Adapter  70  is then screwed onto the flexible pour spout of the bucket while the spout is retracted into the bucket. Threads  82  of adapter  70  engage the threads of the flexible pour spout and pulls shoulder  84  down to the metal ring of the bucket lid. Tapered outer surface  86  of adapter  70  goes into the plastic outer area of the spout below the spout threads for more stability. 
     In the position of barrel  12  shown in FIG. 7 vent groove  18  is in line with adapter  70 , adaptor  70  being shown in the position on barrel  12  it would occupy if attached to a five gallon supply bucket. Vent groove  18  has a length sufficient to permit the upper end thereof to communicate with the atmosphere when the lower end thereof is in communication with the inside of a supply container. In the relative position of adaptor  70  and vent groove  18  shown in FIG. 7, which occurs at the end of each downstroke and the beginning of each upstroke, air can enter the supply bucket through groove  18  thereby preventing a vacuum from forming inside the bucket as oil is pumped out, which might cause the bucket to collapse. 
     If it is desired to use pump  10  to remove hydraulic oil from a 30 gallon half drum or a 55 gallon barrel, barrel bung threads  75  located on the exterior of body  71  are adapted to matingly engage the threads of the bung opening of such half drums or barrels. 
     Although not shown in the drawings, a second longitudinally extending vent groove, similar to vent groove  18 , can be located above vent groove  18  at a location to allow air to enter a 30 gallon half drum and/or a 55 gallon barrel. 
     In operation, the barrel  12  of pump  10  is inserted into an oil supply container. For purpose of discussion it will be assumed the oil container is a five gallon bucket having a flexible pour spout, such as one sold under the registered trademark “FlexSpout” by Rieke Corporation of Auburn, Ind. When barrel  12  touches the bottom of the bucket, adapter  70  is moved down barrel  12  into contact with the flexible pour spout while the spout is retracted into the bucket, and screwed thereon. 
     Oil is pumped out of its supply bucket by pump  10  by pumping piston rod  14  up and down by means of handle  16 . The oil passes through filter  50  and is delivered to the machinery to which quick disconnect  62  is attached. 
     Pump  10  operates as follows. When handle  16  and attached piston rod  14  are moved upwardly (the “upstroke”), the oil trapped above the upper planar surface of piston  42  in the passageway  13  is pushed into cavity  37  and out through outlet nipple  39 . At the same time, as piston  42  rises during its upstroke it creates a low pressure area (vacuum) below the lower planar surface of piston  42 , which causes ball  26  to rise and allows oil to pass from first inlet passageway  23  into second inlet passageway  24 , and from second inlet passageway  24  into the lower part of the central passageway of barrel  12  located below piston  42 . 
     When handle  16  and attached piston rod  14  are moved downwardly (the “downstroke”), ball  26  is forced downward and is seated on shoulder  25 , thereby closing communication between first and second inlet passageways  23  and  24 . Thus, the oil below the lower planar surface of piston  42  is compressed and the force of the compressed oil pushing against the lower planar surface of piston  42  and into passageways  48  causes flapper  49  to rise. When flapper  49  rises it opens communication between the area below the lower planar surface of piston  42  and annular oil passageway  13 , thereby causing oil to flow through fluid passages  48  in piston  42  into annular passageway  13  where it is forced into cavity  37  and out through outlet nipple  39 . 
     Thus both the upward and downward stroke of piston rod  14  pumps oil from its supply container and through filter subassembly  50  and flexible hose  60  to its destination. 
     It can be seen from the foregoing description that pump  10  acts as a vacuum lift pump during the upstroke and as a displacement pump during the downstroke. 
     In order to provide for approximately the same amount of oil to be pumped during the upstroke and the downstroke (so that the pressure applied by the person doing the pumping is about the same during the upstroke and downstroke), it has been found that the ratio of the cross-sectional areas of the central passageway  13   a  of barrel  12  to piston rod  14  should be about 2:1, and the ratio of the cross-sectional areas of annular passageway  13   b  to piston rod  14  should be about 1:1. 
     Although the size of the pump and its various components can be varied in accordance with the ratios just discussed, and it is not intended to limit the invention to specific pump/component dimensions, it has been found desirable for many uses to size the pump and its components to deliver about 2 gallons per minute. This flow rate is achieved at a pumping rate of about 18 to 19 strokes per minute at about 14 ounces per combined up and down stroke where the area of piston rod  14  is about 0.441 inch, the area of bore  13   a  is about 0.833 inch, and the area of annular passageway  13   b  is about 0.392 inch. 
     All of the pumped oil passes through filter  54  which, preferably, is a no-bypass ten micron filter. However, other filters may be used, depending on the oil purity requirements of the machine to which the oil is being fed. 
     Although the discussion of the invention above has referred to hydraulic oil, it is clear that the invention could be used with any low viscosity fluid. 
     It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.