Piston Seals
The nature of the liquid pumped is a major factor
affecting longevity of the piston seal. The piston seal
consists of a seal ring made of either graphite reinforced
PTFE (black) or UHMWPE (yellow) and a spring made
of Titanium (wire). It must be changed whenever a
piston seal leak occurs.
Choose piston seals based on the solvents used:
● The black, polytetrafluoroethylene (PTFE) piston
seals are generally best suited for use with
tetrahydrofuran, hexane, methylene chloride, carbon
dioxide, and low polarity solvents (part number
38013253 for H3 pump head).
● The yellow ultra-high-weight polyethylene (UHMWPE) piston seals are generally best suited
for use with water, aqueous solvents, alcohols, acetonitrile, and polar solvents. Pump heads
are supplied from the factory with the yellow seal (part number 38013261 for H3 pump
head).
The piston, bellows, and spacer can also be replaced while the pump head is disassembled.
Replace a Piston Seal
The following steps should be carried out on a clean, dry
surface. No special tools are required. These instructions
assume that the pump head has been dismounted,
removed and disassembled per the instructions in the
previous section.
1. Remove the piston seal by carefully levering it out with
the end of the Allen wrench. Discard the seal.
2. Clean out any debris from the seal recess using a soft
cloth or an air line.
3. Push a new seal carefully into the recess.
4. Initialize and run-in the new seal(s) as described in
Run-In Procedure on page 52.
Piston
Seal
Figure 38
Piston Seal Location
Figure 39
Piston Seal Removal
45
333/334 HPLC PUMPS | USER’S GUIDE
PISTON SEALS
To Next Page
Loading...
