This consists of 2 flanges, separated by a
short length of tube. One flange (B), is
attached to the cylinder with 4 supplied
bolts, the other end of the assembly is
bolted to the burner front via flange A, by
2 bolts, customer supply.
Because of the different site situations,
certain assumptions are made in order to
arrive at the desired rod length. It can be
seen from table 1 above that the distances
A and C are variable, A is intended to
show a typical position for the HESI tip to
set the correct location within the fuel
zone for reliable ignition. C is the distance between the cylinder and the boiler front, which is
dependent on the method of fixing applied by the customer. It is advisable to ensure that distance C
is no less than 50mm to minimize the heat transfer from the boiler front to the cylinder. The figure
of 100mm was chosen as a sensible starting point. Should exact site mounting and necessary adjust-
ment be known, then these figures can be modified to obtain a more accurate rod length. It should be
noted that rod lengths are in multiples of 0.5M, Other non-standard lengths can be engineered, but
with a time and cost penalty. It can be seen from the diagram that the 2 critical measurements are B
and D, these are fixed for each stroke length.
The fourth shows the second of the Fireye distance pieces, shown below
RET-MT-MT2
RET-MT-MT1
This consists of a flange, attached to
short length of pipe, with a 1" BSP
threaded hole at the other end. The
flange, is attached to the cylinder with
the 4 supplied bolts. The other end of
the assembly is simply screwed on to a
1" nominal bore threaded pipe, which
in turn is welded to the burner front.
This tube can also act as the carrier
tube for the HESI rod, its length being
selected according to the position
required for the HESI rod to successfully ignite the fuel.
Below is a typical retractor supplied fully assembled, ready for mounting the selected HESI rod, and
mounting onto the boiler front
FIGURE 11.
TYPICAL INSTALLATIONS
Figure 14 below shows typical installations of the retraction system. Figure 14/1 shows the cylinder
mounted on to a simple steel bracket which has been welded onto the burner or boiler front plate.
The cylinder is then bolted to the plate via 4 fixing holes. This mounting arrangement is supplied by
the customer.
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