Plunger for a plunger-lift pumping system

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.

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.