|
| Rod Rings |
|
|
| Pressure Breaker rings |
|
|
  Rod Rings: Pressure Breaker rings are not used for a direct seal, but are designed to slow the flow of gas back down the rod on the intake stroke. Without buffering, this back flow could blow the rings off the rod, damaging the garter springs and/or breaking the ring. Pressure Breaker rings may be constructed with any currently available material, but those materials with a low thermal coefficient of expansion and high stiffness are preferable for a stable orifice area. Metal is usually superior to TFE, but Pressure Breakers can be made successfully from some high strength plastics.
|
 P RINGS
P rings use three cuts in the ring as the flow paths for gas. With zero clearance over the rod, the flow controlling orifice in the P ring is the gap that is formed at the segment ends. |
 PA RINGS
PA rings are similar in function to P rings. However in the PA ring, the flow controlling orifice is formed by the clearance between the ring bore and rod. Clearance at the ring segments is zero when installed over the rod. The PA ring provides lower rod loading than the P, but has a more difficult-to-control orifice area. |
|
Wiper Rings
Wiper Rings: Wiper packing acts to maintain oil in the crankcase. Seal rings in the wiper packing also minimize the flow through the packing caused by the pumping action of the crosshead. EM-4 is the standard wiper arrangement that combines a BD seal ring and a 3RWS wiper ring. |
 3RWS WIPER RINGS
The 3RWS is the basic and most commonly used wiper ring combination. The only function of the 3RWS is to wipe the rod and drain the fluid away. The 3 indicates that the RWS ring configuration is doweled to prevent alignment of cuts. |
 560 WIPER RINGS
The 560 wiper ring set is made up of two wiper rings and a butt tangent seal ring that combines the wiper/seal function into one groove. The 560 wiper rings are installed with drain notches of one wiper toward the oil source.
|
 561 WIPER RINGS
The 561 wiper ring set is identical to the 560 wiper ring set with two wiper rings and a butt tangent seal ring that combines the wiper/seal function into one groove. The difference is that the 561 wiper rings are installed with the flat face of one wiper toward the oil source. |
 RWS-BT WIPER RINGS
The RWS-BT is a wiper/seal combination ring installed with drain notches facing the oil source. This is utilized where space is limited.
|
| |
