Plunger for a plunger-lift pumping system

Abstract

A plunger for a plunger-lift pumping system which includes an elongate cylindrical body having a first end and a second end. A plunger suspension coupling is positioned at the first end of the body. A plurality of annular members are provided having central openings and a first radial dimension. The cylindrical body extends through the central openings of the annular members, such that the annular members overlie the cylindrical body. Spacers are provided for maintaining spacing between the annular members. The spacers have a second radial dimension which is less than the first radial dimension, thereby forming circumferential spaces along the cylindrical body between the annular members. A first retainer stops axial movement of the annular members at the first end of the body. A second retainer stops axial movement of the annular members at the second end of the body.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
         1 . A plunger for a plunger-lift pumping system, comprising: 
 an elongate cylindrical body having a first end and a second end;    a plunger suspension coupling at the first end of the body;    a plurality of annular members having central openings and a first radial dimension, the cylindrical body extending through the central openings of the annular members, such that the annular members overlie the cylindrical body;    spacers maintaining spacing between the annular members, the spacers having a second radial dimension which is less than the first radial dimension, thereby forming circumferential spaces along the cylindrical body between the annular-members;    a first retainer stopping axial movement of the annular members at the first end of the body; and    a second retainer stopping axial movement of the annular members at the second end of the body.    
     
     
         2 . The plunger as defined in  claim 1 , wherein the second retainer is detachable, thereby permitting field removal and replacement of the annular members.  
     
     
         3 . The plunger as defined in  claim 1 , wherein the first retainer is integrally formed on the cylindrical body.  
     
     
         4 . The plunger as defined in  claim 3 , wherein the first retainer is an annular shoulder.  
     
     
         5 . The plunger as defined in  claim 1 , wherein the spacers are integrally formed with the annular members.  
     
     
         6 . The plunger as defined in  claim 1 , wherein the annular members are discs.  
     
     
         7 . The plunger as defined in  claim 1 , wherein the first retainer and the second retainer have the same radial dimension and the first radial dimension of the annular members is at least equal to the radial dimension of the first retainer and the second retainer.  
     
     
         8 . The plunger as defined in  claim 7 , wherein at least some of the annular members are sealing annular members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer.  
     
     
         9 . The plunger as defined in  claim 8 , wherein the sealing annular members are flexible and have an “S” shaped peripheral edge, such that the peripheral edge can move in and out like a spring to adjust to variations in well bore diameter while accommodating lateral flexing caused during axial movement of the cylindrical body.  
     
     
         10 . The plunger as defined in  claim 7 , wherein at least some of the annular members are scraper annular members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer, such that they function as scrapers during axial movement of the cylindrical body in a well bore.  
     
     
         11 . The plunger as defined in  claim 7 , wherein at least some of the annular members have a peripheral edge with gaps to allow passage of sand.  
     
     
         12 . The plunger as defined in  claim 1 , wherein the annular members are made out of polymer plastic.  
     
     
         13 . The plunger as defined in  claim 12 , wherein the polymer plastic is selected based upon performance properties, the performance properties including at least one of temperature resistance, chemical resistance, wear resistance, swelling resistance, and flexibility.  
     
     
         14 . A plunger for a plunger-lift pumping system, comprising: 
 an elongate cylindrical body having a first end and a second end;    a plunger suspension coupling at the first end of the body;    a plurality of annular members having central openings and a first radial dimension, the cylindrical body extending through the central openings of the annular members, such that the annular members overlie the cylindrical body;    spacers integrally formed with the annular members for maintaining spacing between the annular members, the spacers having a second radial dimension which is less than the first radial dimension, thereby forming circumferential spaces along the cylindrical body between the annular members;    a first retainer stopping axial movement of the annular members at the first end of the body, the first retainer being an integrally formed annular shoulder on the cylindrical body;    a second retainer stopping axial movement of the annular members at the second end of the body;    the first retainer and the second retainer having the same radial dimension and the first radial dimension of the annular members being at least equal to the radial dimension of the first retainer and the second retainer.    
     
     
         15 . The plunger as defined in  claim 1 , wherein the annular members are discs.  
     
     
         16 . The plunger as defined in  claim 14 , wherein at least some of the annular members are sealing annular members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer.  
     
     
         17 . The plunger as defined in  claim 15 , wherein the sealing annular members are flexible and have an “S” shaped peripheral edge, such that the peripheral edge can move in and out like a spring to adjust to variations in well bore diameter while accommodating lateral flexing caused during axial movement of the cylindrical body.  
     
     
         18 . The plunger as defined in  claim 14 , wherein at least some of the annular members are scraper annular members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer, such that they function as scrapers during axial movement of the cylindrical body in a well bore.  
     
     
         19 . The plunger as defined in  claim 14 , wherein at least some of the annular members have a peripheral edge with gaps to allow passage of sand.  
     
     
         20 . The plunger as defined in  claim 14 , wherein the annular members are made out of polymer plastic.  
     
     
         21 . The plunger as defined in  claim 20 , wherein the polymer plastic is selected based upon performance properties, the performance properties including at least one of temperature resistance, chemical resistance, wear resistance, swelling resistance and flexibility.  
     
     
         22 . A plunger for a plunger-lift pumping system, comprising: 
 an elongate cylindrical body having a first end and a second end;    a plunger suspension coupling at the first end of the body;    a plurality of polymer plastic annular disc members having central openings and a first radial dimension, the cylindrical body extending through the central openings of the annular disc members, such that the annular members overlie the cylindrical body;    spacers integrally formed with the annular disc members for maintaining spacing between the annular disc members, the spacers having a second radial dimension which is less than the first radial dimension, thereby forming circumferential spaces along the cylindrical body between the annular disc members;    a first retainer stopping axial movement of the annular disc members at the first end of the body, the first retainer being an integrally formed annular shoulder on the cylindrical body;    a second retainer stopping axial movement of the annular disc members at the second end of the body, the second retainer being detachably secured to the second end of the body with a threaded engagement, thereby permitting field removal and replacement of the annular members;    the first retainer and the second retainer having the same radial dimension and the first radial dimension of the annular disc members being at least equal to the radial dimension of the first retainer and the second retainer.    
     
     
         23 . The plunger as defined in  claim 22 , wherein at least some of the annular disc members are sealing annular disc members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer.  
     
     
         24 . The plunger as defined in  claim 23 , wherein the sealing annular disc members are flexible and have an “S” shaped peripheral edge, such that the peripheral edge can move in and out like a spring to adjust to variations in well bore diameter while accommodating lateral flexing caused during axial movement of the cylindrical body.  
     
     
         25 . The plunger as defined in  claim 22 , wherein at least some of the annular disc members are scraper annular disc members which have a first radial dimension which is slightly greater than the radial dimension of the first retainer and the second retainer, such that they function as scrapers during axial movement of the cylindrical body in a well bore.  
     
     
         26 . The plunger as defined in  claim 22 , wherein at least some of the annular disc members have a peripheral edge with gaps to allow passage of sand.  
     
     
         27 . The plunger as defined in  claim 22 , wherein the polymer plastic is selected based upon performance properties, the performance properties including at least one of temperature resistance, chemical resistance, wear resistance, swelling resistance and flexibility.