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126B - PAGE 14
4.4 End Cap Removal4.4 End Cap Removal
4.4 End Cap Removal4.4 End Cap Removal
4.4 End Cap Removal
The end cap on the inlet side must be removed to gain access to the filter or shunt assembly. First shut
off the supply of gas to the instrument. Disconnect the Swagelok fitting on the inlet and outlet sides of
the instrument. Remove the four hex bolts holding the end cap to the instrument (see Figure 4.2).
Carefully remove the end cap, filter, wave spring and shunt, noting their order and proper orientation.
NOTE: The Model HFM-230 does not include a wave spring. The shunt can be severely damaged if
dropped. Examine the filter and shunt. If either is dirty or blocked, clean or replace as applicable.
Reassembly is the reverse of the removal procedure.
NOTE: When reinstalling the small range shunt, ensure that corrugated side is down.
4.5 Range Changes4.5 Range Changes
4.5 Range Changes4.5 Range Changes
4.5 Range Changes
Remove end cap and shunt assembly per Section 4.4 above. The 0-10 sccm to 0-300 sccm range
shunt has tubes, while the medium range shunt is built from a coil of corrugated stainless steel foil. The
medium range shunt has a disk assembly with two large, one medium, and one small hole. To change
ranges, the disc on the inlet of the shunt should be loosened, turned and retightened to expose the
number of holes or tubes as listed below for the range desired.
SIZESIZE
SIZESIZE
SIZE
RANGE RANGE
RANGE RANGE
RANGE
SHUNT SETUPSHUNT SETUP
SHUNT SETUPSHUNT SETUP
SHUNT SETUP
SMALL .......................................... 0-10 sccm ............................................................................... 0 tubes
........................................................ 0-30 sccm ................................................................................ 1 tube
........................................................ 0-50 sccm ............................................................................... 2 tubes
........................................................ 0-100 sccm ............................................................................. 4 tubes
........................................................ 0-250 sccm ........................................................................... 10 tubes
MEDIUM ....................................... 0-.3 slpm ...................................................................... smallest hole
........................................................ 0-1 slpm ........................................................................ medium hole
........................................................ 0-3 slpm .......................................................... 1 large and small hole
........................................................ 0-5 slpm ................................................................... both large holes
........................................................ 0-10 slpm ........................................................................ half-washer
........................................................ 0-30 slpm .................................................................washer removed
LARGE........................................... 0-50 slpm ................................................................................ 1 hole
........................................................ 0-100 slpm ............................................................................. 2 holes
........................................................ 0-150 ............................................................................... slpm3 holes
........................................................ 0-300 ................................................................ slpmwasher removed
........................................................ 0-500 ............................................................... slpm washer removed
NONO
NONO
NO
TETE
TETE
TE: These ranges are for Air at Standard Temperature and Pressure.
Fig.4.2Fig.4.2
Fig.4.2Fig.4.2
Fig.4.2