Page 190 - Reciprocating Compressors Operation Maintenance

176 Reciprocating Compressors: Operation and Maintenance

Each of these conditions or patterns is considered to be "normal" and
will exist alternately during normal operation.
PACKING RING TYPES

There are several types of packing rings available.

1. Radial and Tangent Set
This is a true sealing ring, made up of a pair of rings, the first of
which is radially cut with considerable clearance at each end. The
second ring is tangentially cut forming an overlapping seal joint that
prevents gas passage from the outside periphery toward the rod
bore. The inner radial cuts of this tangent ring are arranged so that
they occur approximately between the radial cuts of the first ring in
the pair. In this manner, gas passage along the rod is blocked so that
there is no through escape.
The rings are doweled to maintain this staggered cut arrangement.
When the rings are together as shown in Figure 3-38, no gas passage
from the outside is possible because of the tangent cut. As indicated,
this type of ring is single-acting or directional in that it seals pres-
sure from one side only.

SINGLE ACTING RING
PROPER SIDE MUST FACE PRESSURE
France Type 211
Cook Type Bt

this is the most common sealing ring -
available in alt materials and suitable for alinosi
all applications. It is single acting; that is, seals in
one direction only.

PRESSURE SIDE
FIGURE 3-38. Single-acting sealing rings. Radically cut side must face pres-
sure (Source: Worthington Compressor Co., Service Manual).