background image

PO BOX 1909, ROHNERT PARK, CA 94927-1909, U.S.A. • PHONE 707-588-2000 • FAX 707-588-2020

tion from the earlier injection. This liquid will
exit out vent tube 5.

b) Follow steps a-d in Section 8.0.

10.0 ADJUSTING FOR HIGHER PRES-
SURE OPERATION/LEAKAGE

The valve has been factory-set to hold 345

bar. If you need operation to a higher pressure
or if there is a leak between stator and stator
ring proceed as follows.

With the system pressurized, back the three

set screws part-way out of the stator. Tighten
each of the three stator screws 1/8 of a turn,
continue to do so until the leak stops and the
valve is holding the pressure you want.
Confirm that the gap between the stator and
stator ring is equal around the valve. After the
leak has stopped tighten the set screws until
they touch the stator ring. Replace the rotor
seal if the leak continues.

NOTE: If the vent tubes from ports 5 and

6 do not have their outlet ends at the same
horizontal level as the needle port, siphoning
can result, which is often misinterpreted as
a leak.

11.0 MAINTENANCE

With normal use the valve will give many

thousands of injections without trouble. The
rotor seal wears with use and is the only part
that needs routine replacement. The main
causes of early failure are:

a) the wrong needle tip can chip the

ceramic stator face which then causes deep
scratching of the rotor seal surface or,

b) abrasive particles in the sample can

scratch the rotor seal surface.

11.1 CHANGING THE ROTOR SEAL

To change the rotor seal (P/N 7125-047)

refer to Fig. 5 and proceed as follows:

a) Remove the three stator screws.
b) Remove the stator, stator face assembly

and stator ring from the body.

c) Pull the rotor seal off the pins.
d) Leave isolation seal and bearing ring in

place. See Section 12.2 for reassembly.

11.2 REASSEMBLY

To reassemble the valve proceed as

follows and refer to Fig. 5:

a) Line up rotor seal as shown in Fig. 6.

The rotor seal slots face the stator.

b) Replace the stator ring so that the two

stop pins enter the mating holes in the body.
The rotor pin must be between the two stop
pins.

c) Put the stator face assembly on the

stator. Line up the small notch in the rim of the
assembly with port 1 of the stator.

d) Mount the stator and stator face

assembly on the valve by pushing it onto the
two pins on the stator ring.

f) Put the three stator screws in place.

Tighten each an equal amount until the screws
are tight. The three set screws will keep the
space even between the stator and stator ring.

11.3 SPARE PARTS
7125-047  Vespel Rotor Seal (standard)
7125-079 Tefzel Rotor Seal (high pH)

12.0 OPERATING SUGGESTIONS AND
TROUBLESHOOTING

12.1 LEAKAGE

  If you see liquid between the stator and

stator ring, tighten the pressure adjusting screw
as explained in Section 11.0.  Replace the
rotor seal if the leak continues.

12.2 NEEDLE SEAL LEAKAGE

Since the outside diameter of syringe

needles can be different from syringe
tosyringe, the needle seal (Teflon sleeve in the
rotor seal) may not seal correctly around a
needle which is smaller than average. This
will result in a loss of accuracy in loading
the sample.

12.3 USE OF AQUEOUS BUFFERS OR
SALT SOLUTIONS
  To prevent the formation of salt crystals in
the valve, flush out the flow passages and the
injection port with water after using salt
solutions.

12.4 USE OF HIGH pH SOLUTIONS

The standard rotor seal is Vespel, a

polyimide with good wear resistance. It
is sensitive to alkaline attack, so avoid
solutions having a pH of 10 or more. Use the
Tefzel rotor seal for alkaline solutions (see
Section 11.3).

12.5 ACCURACY OF SAMPLE LOOPS
  Sample loop sizes are not actual values.  The
actual volume can differ by up to 10% for a
20-uL loop.  There is a greater difference for
smaller loops. Use partial filling if you must
know the actual volume injected.

13.0 WARRANTY

All Rheodyne valves are warranted

against defects in materials and workman-
ship for a period of one year following date
of shipment by Rheodyne. Rheodyne will
repair or  replace any Rheodyne product
that fails to conform to the foregoing war-
ranty, at no charge to the customer, provided
that the valve is returned to Rheodyne's
factory, transportation prepaid. The forego-
ing is Rheodyne's sole warranty of its prod-
ucts, and all other warranties, express or
implied, including any implied warranties
of merchantability or fitness for any particu-
lar purpose are hereby disclaimed. Under no
circumstances will Rheodyne be liable for
any consequential or incidental damages
attributable to any Rheodyne valves, even if
Rheodyne has been placed on notice of the
possibility of such damages.

14.0 RETURN OF VALVES

Products may not be returned which are

radioactive or contaminated by infectious
agents, or other materials that may constitute
health hazards to Rheodyne employees.

Figure 5: Model 7125 Exploded View

Notch

Stop Pins

Figure 6: Rotor Seal Orientation (view from stator)

Handle Assembly

Thrust Bearing

Body

Set Screws (3)

Stator Ring

Stop Pins (2)

Rotor Seal

Isolation Seal
(spring loaded)

Bearing Ring

Needle Port Tube
Assembly

Spring Washers (4)

Needle Seal

Stator

Stator Face Assembly

Stator Screws (3)

Rotor Pin

Seal Pins (4)

Needle Guide

Отзывы: