Heavy Duty Balanced Opposed Compressors

FOR MODELS: JG AND JGA SECTION 5 - MAINTENANCE
Type "BTR" Single Acting Seal Set
This set is made up of three rings. It seals in one direction only. The first ring (pressure side)
is radially cut. The installed total end gap is 0.046 to 0.078 inches (1.17 to 1.98 mm) for
Teflon and 0.093 to 0.125 inches (2.36 to 3.18 mm) for bronze and Polyimide. The second
ring is a tangentially step cut ring. The first two rings are doweled so the cuts are staggered
from one ring to the other. The third ring is called a back-up ring and is radially cut. The bore
in this ring is larger than the rod diameter. This allows the radial joints to be tight together
forming a gas seal. No dowel is necessary for this ring. See Figure 5-14:
Radial Cut
Alignment
Dowel
FIGURE 5-14: TYPE “BTR” SINGLE ACTING SEAL SET
Type “AL” Double Acting Seal Set
Tangential
Step Cut
B T R
Radial Cut
Pressure Side Ring Middle Ring
Letters toward pressure/cylinder
Back-Up Ring
Material: Cast Iron
This set is made up of five rings. The center three are radial cut and the two outboard rings
are step-tangent cut. The last two rings on each end are doweled together to stagger the
cuts. The center ring, along with the two adjacent rings, form a wedge that overcomes rod
friction and forces the set to have constant contact against both groove faces during either
direction of rod travel. The installed total end gap is 0.062 to 0.093 (1.57 to 2.34 mm). This
ring set is designed for gas purge applications. See Figure 5-15:.
Material: Teflon
FIGURE 5-15: TYPE “AL” DOUBLE ACTING
PAGE 5 - 28 11/01
BTR