Dense phase pump with easily replaceable components

Abstract

A dense phase pump has two housings that are attached together using a single releasable fastener. The fastener can be released to allow the two housings to be separated thereby providing access to replaceable components. The replaceable components may include one or more pinch valves or one or more barrier elements. A pinch valve for a dense phase pump has a shape or profile for aligning the pinch valve when the pinch valve is installed in a pinch valve body. The pinch valve optionally has two end flanges, with each end flange having a shaped periphery. The two end flanges may have the same size and shape so that the pinch valve can be installed in either of two orientations that are inverse. A dense phase pump has a pump chamber that can be purged by purge gas that enters the pump off-axis from a purge path axis.

1 . A dense phase powder pump, comprising:
 a first housing, a gas permeable filter disposed in said first housing,   a pinch valve housing adapted to receive at least one pinch valve,   a single releasable fastener that attaches said pinch valve housing and said first housing together.   
     
     
         2 . The dense phase pump of  claim 1  comprising a second gas permeable filter disposed in said first housing, and said pinch valve housing is adapted to receive at least four pinch valves. 
     
     
         3 . The dense phase pump of  claim 1  wherein said releasable fastener comprises a threaded bolt. 
     
     
         4 . The dense phase pump of  claim 1  comprising at least one barrier element disposed in said pinch valve housing. 
     
     
         5 . The dense phase pump of  claim 2  comprising at least four barrier elements disposed in said pinch valve housing. 
     
     
         6 . The dense phase pump of  claim 1  wherein said pinch valve housing and said first housing comprise keyed elements for aligning said pinch valve housing with said first housing during assembly of the dense phase pump. 
     
     
         7 . The dense phase pump of  claim 6  wherein said keyed alignments restrict rotation of said pinch valve housing relative to said first housing. 
     
     
         8 . The dense phase pump of  claim 1  wherein said pinch valve housing and said first housing comprise external alignment indicia for aligning said pinch valve housing with said first housing during assembly of the dense phase pump. 
     
     
         9 . The dense phase pump of  claim 1  wherein said pinch valve housing and said first housing comprise stop surfaces that engage each other to prevent over-tightening of said releasable fastener. 
     
     
         10 . The dense phase pump of  claim 9  wherein said stop surfaces are disposed on column structures in said pinch valve housing and said first housing, wherein said column structures are axially aligned with each other during assembly of the dense phase pump. 
     
     
         11 . The dense phase pump of  claim 10  wherein said column structures provide a bore that receives said releasable fastener. 
     
     
         12 . The dense phase pump of  claim 1  wherein said first housing comprises a pump body and a first powder flow block, said dense phase pump comprises a second powder flow block, wherein said pinch valve housing is disposed between said first powder flow block and said second powder flow block, said single releasable fastener attaching said second powder flow block and said pinch valve housing to said first powder flow block. 
     
     
         13 . The dense phase pump of  claim 1  wherein said first housing comprises a pump body and a first powder flow block, said first powder flow block comprising a first powder flow passage and a second powder flow passage, said first powder flow passage and said second powder flow passage being in fluid communication with said gas permeable filter so that powder flows into and out of said at least one gas permeable filter when the pump is operating. 
     
     
         14 . The dense phase pump of  claim 13  comprising at least a first pinch valve and a second pinch valve disposed in said pinch valve housing, and further comprising a second powder flow block, said second powder flow block comprising a third powder flow passage and a fourth powder flow passage, said third powder flow passage and said fourth powder flow passage being in fluid communication with said first pinch valve and said second pinch valve respectively so that powder flows into and out of said at least one gas permeable filter when the pump is operating by flowing through said second powder flow block and said pinch valve housing and said first powder flow block. 
     
     
         15 . The dense phase pump of  claim 14  wherein said single releasable fastener attaches said second flow block and said pinch valve housing to said first flow block. 
     
     
         16 . The dense phase pump of  claim 1  wherein said pinch valve housing is separable from said first housing by releasing only said single releasable fastener. 
     
     
         17 . The dense phase pump of  claim 16  wherein said pinch valve housing retains at least one barrier element. 
     
     
         18 . The dense phase pump of  claim 17  wherein said at least one barrier element is operable to block powder from entering a pressure bore that is in fluid communication with a pinch valve pressure chamber for said at least one pinch valve. 
     
     
         19 . The dense phase pump of  claim 18  wherein said pressure bore alternately applies positive pressure and suction to said pinch valve pressure chamber. 
     
     
         20 . A pinch valve, comprising:
 an annular body having a central flow passage therethrough,   a first end flange on a first end of said annular body and a second end flange on an opposite end of said annular body, wherein each said first end flange and second end flange have a larger outside diameter than said annular body,   at least one end flange of said first end flange and said second end flange having a shaped periphery for aligning the pinch valve when the pinch valve is installed in a pinch valve body.   
     
     
         21 . The pinch valve of  claim 20  wherein said at least one end flange has a circular periphery with at least one flat portion. 
     
     
         22 . The pinch valve of  claim 21  wherein said at least one end flange circular periphery has two flat portions. 
     
     
         23 . The pinch valve of  claim 20  wherein said first end flange and said second end flange have maximum outside diameters that are the same. 
     
     
         24 . The pinch valve of  claim 20  wherein each of said end flanges have the same size and shape so that the pinch valve can be installed in either of two orientations that are inverse with respect to each other. 
     
     
         25 . The pinch valve of  claim 24  wherein each of said end flanges has a circular periphery with two flat portions. 
     
     
         26 . A dense phase pump, comprising:
 a pump housing comprising at least one pressure chamber and a gas permeable filter disposed in said pressure chamber, said gas permeable member comprising a longitudinal axis,   a source of positive pressure in fluid communication with said pressure chamber and a source of negative pressure being in fluid communication with said pressure chamber so that when said pressure chamber is under negative pressure powder is drawn into a first end of said gas permeable filter and when said pressure chamber is under positive pressure powder is pushed out of said gas permeable filter through said first end,   a check valve operably coupled to a second end of said gas permeable member so that when said check valve is open, purge air flows axially into said gas permeable member from said second end to said first end,   a purge air inlet into said pump housing wherein purge air enters said pump housing along a purge air axis that is transverse said gas permeable member longitudinal axis, said purge air inlet being in fluid communication with an inlet of said check valve.   
     
     
         27 . The dense phase pump of  claim 26  wherein said check valve has a flow path between an inlet and an outlet along a check valve axis, said check valve axis being coaxial with said gas permeable member longitudinal axis and being transverse said purge air inlet axis. 
     
     
         28 . The dense phase pump of  claim 26  comprising an air manifold, said air manifold having a purge air outlet, said pump housing purge air inlet being in fluid communication with said air manifold purge air outlet. 
     
     
         29 . The dense phase pump of  claim 28  wherein said pump housing is attached to said air manifold so that said pump housing purge air inlet is in fluid communication with said air manifold purge air outlet. 
     
     
         30 . The dense phase pump of  claim 29  wherein said air manifold purge air outlet is presented on a planar surface of said air manifold, said pump housing purge air inlet is presented on a planar surface of said pump housing, said planar surface of said pump housing facing said planar surface of said air manifold with a seal therebetween. 
     
     
         31 . A method for replacing a pinch valve disposed in a dense phase pump, comprising the steps of:
 releasing a single releasable fastener to release a pinch valve housing that was attached to a pump housing by said single releasable fastener,   removing said pinch valve housing from attachment with said pump housing to provide access to a pinch valve disposed in said pinch valve housing,   removing either of: 1) said pinch valve for replacement with a different pinch valve, or 2) said pinch valve housing for replacement with a different pinch valve housing.   
     
     
         32 . The method of  claim 31  comprising the step of removing at least one barrier element from said pinch valve housing for replacement with a different barrier element. 
     
     
         33 . The method of  claim 31  wherein said pinch valve can be replaced without disconnecting one or more hoses that are connected to the dense phase pump during normal operation of the dense phase pump. 
     
     
         34 . A dense phase powder pump, comprising:
 a first housing, a gas permeable filter disposed in said first housing,   a second housing adapted to receive at least one replaceable component,   a single releasable fastener that attaches said second housing and said first housing together.   
     
     
         35 . The dense phase pump of  claim 34  comprising a second gas permeable filter disposed in said first housing, and said second housing is adapted to receive at least four replaceable components. 
     
     
         36 . The dense phase pump of  claim 35  wherein said replaceable components comprise pinch valves. 
     
     
         37 . The dense phase pump of  claim 35  wherein said replaceable components comprise at least four barrier elements. 
     
     
         38 . The dense phase pump of  claim 34  wherein said releasable fastener comprises a threaded bolt. 
     
     
         39 . A pinch valve, comprising:
 an annular body having a central flow passage therethrough,   a first end flange on a first end of said annular body and a second end flange on an opposite end of said annular body,   said first end flange and said second end flange having a shaped periphery for aligning the pinch valve when the pinch valve is installed in a pinch valve body, wherein said first end flange is radially offset from said second end flange.   
     
     
         40 . A pinch valve, comprising:
 an annular body having a central flow passage therethrough,   a first end flange on a first end of said annular body and a second end flange on an opposite end of said annular body,   said first end flange and said second end flange comprise a non-circular peripheral shape for aligning the pinch valve when the pinch valve is installed in a pinch valve body.   
     
     
         41 . The pinch valve of  claim 39  or  40  wherein said first end flange and said second end flange comprises alignment indicia thereon. 
     
     
         42 . The pinch valve of  claim 39  or  40  wherein said first and flange and said second end flange have matching shapes. 
     
     
         43 . The pinch valve of  claim 39  or  40  wherein the pinch valve may be installed in a first longitudinal orientation or a second longitudinal orientation that is inverse from said first longitudinal orientation. 
     
     
         44 . A pinch valve housing, comprising:
 a body having at least one pinch valve pressure chamber, said pinch valve pressure chamber having a longitudinal axis X,   a pressure passage that extends from an inlet port to said pinch valve pressure chamber, said pressure passage opening to said pinch valve pressure chamber at an oblique angle θ relative to said longitudinal axis X.   
     
     
         45 . The pinch valve housing of  claim 44  comprising alignment indicia on an external surface of said body. 
     
     
         46 . A pinch valve housing, comprising:
 a body comprising at least one pressure chamber,   a pinch valve disposed in said pressure chamber,   said pinch valve comprising first and second end flanges that each have a non-circular peripheral shape.   
     
     
         47 . The pinch valve housing of  claim 46  comprising a pressure passage that extends from an inlet port to said pressure chamber, said pressure chamber having a longitudinal axis X, said pressure passage opening to said pinch valve pressure chamber at an oblique angle θ relative to said longitudinal axis X. 
     
     
         48 . The pinch valve housing of  claim 46  comprising alignment indicia on an external surface of said body. 
     
     
         49 . The pinch valve housing of  claim 46  wherein said end flanges are radially offset from one another. 
     
     
         50 . The pinch valve housing of  claim 46  comprising a pressure passage having an opening into said pressure chamber. 
     
     
         51 . The pinch valve housing of  claim 50  wherein said pinch valve comprises ribs that are received in slots in said body, said slots being radially offset by an angle β from said opening. 
     
     
         52 . A pinch valve housing, comprising:
 a body comprising at least one pressure chamber,   a pinch valve disposed in said pressure chamber,   an inlet port in fluid communication with said pressure chamber,   a barrier element disposed in said inlet port.   
     
     
         53 . The pinch valve assembly of  claim 52  wherein said barrier element comprises a barrier filter that comprises a gas permeable material. 
     
     
         54 . The pinch valve housing of  claim 52  comprising alignment indicia on an external surface of said body. 
     
     
         55 . A pinch valve housing, comprising:
 a body having a central longitudinal axis, said body comprising at least a first pressure chamber and a second pressure chamber, each of said first pressure chamber and said second pressure chamber being non-circular, said first pressure chamber being oriented in a first direction about said central longitudinal axis and said second pressure chamber being oriented in a second direction about said central longitudinal axis that is different from said first radial direction.   
     
     
         56 . The pinch valve housing of  claim 55  wherein each of said first and second pressure chambers comprises a pair of longitudinal slots. 
     
     
         57 . The pinch valve housing of  claim 55  comprising alignment indicia on an external surface of said body. 
     
     
         58 . A pinch valve housing, comprising:
 a body having a central bore that extends longitudinally through said body and is adapted to receive a fastener.   
     
     
         59 . A pinch valve housing comprising:
 a body comprising at least one pressure chamber,   a pinch valve disposed in said pressure chamber,   said pinch valve including indicia that indicates an orientation of said pinch valve in said body.   
     
     
         60 . The pinch valve housing of  claim 60  comprising alignment indicia on an exterior surface of said body. 
     
     
         61 . The dense phase pump of  claim 12  comprising a plurality of fasteners for attaching said first powder block to said pump body. 
     
     
         62 . The dense phase pump of  claim 13  comprising a plurality of fasteners for attaching said first powder flow block to said pump body. 
     
     
         63 . The dense phase pump of  claim 12  comprising