Unitary body bypass plunger and valve cage
A bypass plunger combines a unitary or one-piece hollow body-and-valve cage, retains a dart valve within the valve cage portion of the hollow body using a threaded retaining nut secured by crimple detents. A series of helical grooves surround the central portion of the outer surface of the hollow body of the plunger to control spin during descent. A canted-coil-spring disposed within the retaining nut functions as a clutch. The valve cage includes ports that may be configured to control flow through the plunger during ascent. Other embodiments include clutch assemblies using canted-coil springs with split bobbins, and valve stems surfaced to achieve specific functions.
1. A bypass plunger, comprising:
a hollow plunger body and valve cage formed as one integrated piece having first and second ends, the valve cage for enclosing a dart valve and a split bobbin clutch assembly formed at the second end thereof and having first threads at the distal end thereof for receiving a retaining device for retaining the dart valve, a partition nut the partition nut adjustably spacing the dart valve and the split bobbin clutch assembly within the valve cage; wherein
the dart valve having a valve head connected to a valve stem, the dart valve reciprocatingly disposed within the valve cage such that the valve head is oriented toward a valve seat formed within the hollow body; and
the retaining device having second threads formed on the outer surface of one end for threading the retaining device into the first threads of the valve cage.
2. The bypass plunger of claim 1 , wherein the valve cage comprises:
a tubular portion of the lower end of the bypass plunger having a plurality of outward-angled ports in the walls of the valve cage to enable fluid flow there-through during descent of the bypass plunger; wherein
the ports are each disposed at an acute angle with the longitudinal axis of the valve cage and are separated by substantially equal angles around the wall of the valve cage.
3. The bypass plunger of claim 1 , wherein:
the dart valve is disposed to move between a closed position in contact with the valve seat formed in the hollow body proximate the valve cage portion of the hollow body and an open position disposed away from the valve seat.
4. The bypass plunger of claim 3 , wherein the valve stem comprises:
a cylindrical surface ground to a predetermined surface roughness.
5. The bypass plunger of claim 1 , wherein the retaining device comprises:
a retaining nut having the second threads formed on the outer surface of one end that allow the retaining nut to be threaded into the first threads of the valve cage.
6. The bypass plunger of claim 1 , wherein:
the retaining device is locked from turning by at least one crimple detent extending inward from the surface of the valve cage along a radii of the valve cage into a corresponding relieved space in the proximate second threads formed in the outer surface of the retaining device.
7. The bypass plunger of claim 1 , wherein:
the split bobbin clutch assembly is disposed on the valve stem within the valve cage between the partition nut and the retaining device.
8. The bypass plunger of claim 7 , wherein:
the partition nut includes an externally threaded outer surface threaded into an internal thread disposed within the valve cage for retaining the split bobbin clutch assembly in position against the retaining device.
9. The bypass plunger of claim 7 , wherein the split bobbin clutch assembly is clamped around the valve stem by one or more garter springs.
10. The bypass plunger of claim 9 , wherein the garter springs comprise canted coil springs having coils wound at an acute angle to a centerline of the spring.