Wear Ring Cleaning And Replacement; Flushing The Cylinder; Gas Solvent Changeover - Teledyne D series Installation And Operation Manual

9.10 Wear Ring Cleaning
and Replacement

9.11 Flushing the Cylinder

9.11.1 Gas Solvent
Changeover
Section 9 Pump Maintenance, Troubleshooting, and Servicing
the cylinder mounting block (the cylinder will no longer
turn). Do not overtighten.
6. Unscrew the cylinder until the inlet and outlet ports are
lined up as you had them before. Do not unscrew the cylin-
der more than one full turn from the stop position.
7. Lock the cylinder by tightening the locking screw on the
front of the cylinder mounting block to 30 in-lbs (3.4 N-m).
Reinstall covers.
Although the wear ring does not routinely need to be replaced,
occasionally it becomes worn or damaged, depending on how the
pump has been used. Teledyne Isco recommends that when
replacing the seal or cleaning the piston, check the wear ring for
any signs of deterioration.
1. Follow the instructions in section 9.9, Seal Cleaning and
Replacement, to access the cylinder.
2. Remove the piston seal retainer and slide off the seal. The
wear ring should then slide easily up and off the piston.
The wear ring prevents the piston from direct metal-to-metal
contact with the cylinder wall, and should, therefore, extend at
least 0.010" beyond the circumference of the piston lip. Check the
bottom of the wear ring, which rests on the piston lip, for
extrusion or any unevenness. If there is an indentation (of
0.0010" or more) marking the outline of the piston lip, then you
should replace the wear ring. However, if the surface is smooth,
the wear ring does not need replacing.
After cylinder/seal maintenance or during modifier (liquid
solvent) change, the pump cylinder should be flushed to remove
possible residue.
The way in which the cylinder is flushed will depend on your
pumping system and whether you are pumping a liquefied gas
such as CO (see Section 9.11.1) or a liquid modifier such as
2
methanol (see Section 9.11.2).
This procedure is used when changing from one gaseous solvent
to another.
1. Close the valve on the fluid supply tank so that no solvent
is supplied to the system.
2. Turn the controller ON.
3. Run the pump until the cylinder is empty. If there was any
pressure in the system, wait until all the pressure bleeds
off.
4. Change the solvent tank.
5. Close the pump outlet valve.
6. Open the valve on the tank to repressurize the system.
D Series Syringe Pumps
9-17