Applications Manual Bosch Geothermal Heat Pumps
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Bosch Thermotechnology Corp.
Data subject to change
Fig. 45 Socket fusion joint inspection
Butt fusion is the joining procedure where two pipe ends
are simultaneously heated to a plastic state by a heater
plate and brought together to form the heat-fused joint
(Fig. 46, 47). A single heat fusion process is used to form
the joint between the two pipe ends. This process is
performed by using specially designed machines which
provide for securely holding the two pieces of pipe to be
fused, aligning them, trimming and squaring their ends,
heating the surfaces to be joined with a heater plate, and
butting them together while they remain in a plastic state,
producing a double rolled back bead. This method requires
the technician to assemble the required equipment and
tools prior to fusing. Then he/she must prepare the fusion
machine correctly, clean and heat the heater to the proper
temperature, prepare the pipe ends properly for fusion,
heat the pipe ends and fuse the pipe properly.
No Gaps or
Cavities
Proper Alignment
of Pipe Ends
Uniform
Melt Bead
Fig. 46 Butt fusion
Courtesy of International Ground Source Heat Pump Association/Oklahoma
State University
Fig. 47 Butt fusion visual inspection
Sidewall butt fusion joining is used when joining the
concave surface of a service saddle to the convex surface
on the sidewall of a pipe (Figure 71). This procedure
involves heating these surfaces with appropriate convex-
and concave-shaped heaters and then butting these
surfaces together.
Melt Bead
Encircling
Base of
Fitting
Complete
Melt
Pattern
A Complete
Triple Roll Bead
1) One on the pipe
2) One on the fittting
3) One between the two
(2)
(3)
(1)
Fig. 48 Sidewall butt fusion
Courtesy
of International Ground Source Heat Pump Association/Oklahoma State
University
