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b. Use appropriate fittings to attach a 1/4-inch supply line to the tank . Install an air shut-off valve on the tank or
at a location convenient to the driver to permit the air supply to be easily turned off for safety purposes or as
other conditions require .
c. An automatic shut-off valve also is recommended in the air line near the tank . This valve acts as a circuit
breaker, automatically shutting off air flow if the supply line is accidentally broken between the valve and the
sampler . Government regulations or plant safety codes often require this valve . Select a valve with sufficient
flow capacity to operate the sampler at its maximum cycle rate .
d. Use a 1/4-inch bulkhead fitting, provided with the sampler package, to penetrate a dry compartment wall . Drill
a 3/8-inch hole through the wall, insert the bulkhead fitting and tighten securely with locking nuts .
e. Run a 1/4-inch OD tube from the shut-off valve to the bulkhead fitting connection on the outside of the dry
compartment . Use 1/4-inch OD copper or other approved metal tubing . Support and protect the tubing along
the truck chassis to prevent damage from road conditions or vibration . Tighten all connections securely .
f.
Inside the dry compartment, run 1/4-inch OD flexible plastic tubing, provided with sampler package, from
interior bulkhead fitting to the 1/4-inch tube fitting on the left side of the sampler controller (regulator input) .
Tighten compression fittings securely .
2. TRUCKS WITHOUT AIR SUPPLY: Where trucks use hydraulic brakes, or other conditions prevent connecting to an
on-board air supply, a small air receiver tank can be installed to operate the sampler . An appropriate tank size is 6
to 12 gallon capacity, and it should be code rated (U .S . Dept . of Transportation or equal) for service to at least 120
psi (827 KPa) . Tanks can be obtained locally from firms that build or repair truck air brake systems, or an air tank
package is available from Sentry Equipment Corp . A typical supplier is Bendix/Westinghouse .
A typical 7-1/2 gallon air reservoir (part of the air tank package), charged to 120 psi, will provide approximately
2000 sampler cycles before recharging . At 0 .5 cc of sample per cycle, this equals one liter of sample, or
approximately 25 samples of 40cc quantity each .
INSTALLATION:
a. Determine an appropriate location on the truck for the air reservoir . It should be protected from road damage,
but accessible for recharging with compressed air .
b. Ensure that the air tank is equipped with a water blow-off valve at its lowest point . Also supply an air inlet (tire-
valve fitting or equal) . Both are provided with the Sentry air tank package .
c. Pipe the air outlet from the top or end of the tank with fittings to attach a 1/4-inch OD supply line . A shut-off
valve in the supply line is recommended . Complete the installation in same manner as outlined for trucks with
air brake systems .
Typical Operation Procedure
Following is a typical milk pickup sequence using the ISOLOK MSA sampler . Steps not covered should be carried out in
accordance with standard methods as prescribed by local, state or other health regulatory agencies .
1. The ON-OFF switch remains "on" continuously when the AC power supply package is installed . Starting and
stopping the sampler usually is controlled by switching the power to the pump motor on or off . Use the ON-OFF
switch to start and stop sampler operation when power for the sampler controller comes directly a truck electrical
system (DC power supply package or equivalent installation) . Turn the switch off when sampler operation is not
desired .
2. Ensure the compressed air supply is ON .
3. Attach the sample container (bottle, bag or vial) to the sampler .
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Sentry Equipment Corp
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