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5.3 Pump Tubing
5.3.1 Inspection of Pump
Tubing
The pump tube serves two functions: it is a pump tube in the
peristaltic pump and a distribution tube, routing the sample
liquid from the pump outlet to the sample bottle.
The pump tube consists of a single 42-inch (103.8 cm) piece of
medical-grade Silastic silicone rubber tubing. Teledyne Isco uses
medical-grade tubing because of its superior mechanical prop-
erties and because it does not contain any organic materials.
Nonmedical-grade silicone rubber tubing can contain organic
vulcanizing agents. During vulcanizing, these agents are con-
verted into compounds which can leach into the sample. The
medical-grade silicone tubing Teledyne Isco supplies for use with
the 3700 Sampler will not contribute any organic material to the
sample.
Be sure the power is disconnected from the unit before you
exchange the pump tubing. The pump is extremely
powerful. If the sampler activates the pump while you are
manipulating the tubing within the pump, you may be
seriously injured.
The pump tubing is extremely durable. However, the constant
mechanical strain placed on the tubing by the peristaltic action
of the pump eventually causes the tubing to fatigue and fail.
Remove the cover periodically to inspect the pump tubing for
wear inside the pump. Check the tubing for cracks where the
pump roller compresses the tubing. Replace the worn out pump
tubing with a new pump tube, if necessary.
Note
The importance of regular tubing replacement cannot be over-
stated. The key is to replace the tube before failure, not after.
When a pump tube ruptures, grit and other abrasive debris can
be driven into the pump shaft seal. Over time, this abrasive
material will degrade the pump seal, jeopardizing the
NEMA 4x 6 rating of the controller.
Failure to maintain the pump tube may result in permanent
damage to the sampler. Check the condition of the pump tube
regularly and if the tube shows signs of fatigue or wear,
replace it immediately. A properly maintained sampler will pro-
vide the years of reliable service that is expected of a Teledyne
Isco Sampler.
The inspections should be fairly frequent when the liquid being
sampled contains a high percentage of suspended solids. If the
liquid is relatively free of solids, the inspections can be less fre-
quent. The Tubing Life configure option reports the number of
pump counts elapsed during the life of the pump tube.
3700 Portable Samplers
Section 5 Routine Maintenance
WARNING
5-3
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