Fill/Discharge Valve Groups and Associated CIPS/R Piping
The bottom fill/bottom empty configuration shown above would function as follows ...
- For the production run, the moveable elbow at each tank outlet valve would connect to the fill/empty line leading to the valve group. The tank could be filled or emptied under automatic control by proper operation of the process valves and pumps.
- To clean a tank, (a) process flow would be terminated, (b) the moveable elbow would be reinstalled between the tank outlet valve and the tank CIP return line and (c) the cap removed from the return line would be used to temporarily close the fill/empty line. These fittings must be rinsed and cleaned when making the connection change. In this configuration, the tank is isolated from the process piping via the swing-elbow. The U-bend on the cleaning hook-up station would be properly positioned to supply solution to the desired spray.
- At the end of the production run, and with product possibly remaining in the tanks, the removable elbow would again be manually cleaned and repositioned to connect the fill/empty line to the tank CIP return line now used as a CIP tie line. The cap would be placed on the tank outlet valve, providing protection against contamination or inadvertent loss of product due to improper operation of that valve when the tank is not connected to the process piping system.
- When cleaning the tanks, the tank outlet valve must be "pulsed" to clean the valve stem O-ring and this is generally accomplished during the drain period following the pre-rinse, solution wash, and post-rinse.
- When cleaning the lines, the fill/discharge valves in the valve group must be sequenced to provide controlled flow through each portion of the interconnecting piping and to clean the valve stem O-rings.
- Experience has demonstrated that each valve should be moved 3-4 times during the pre-rinse, 4-6 times during the solution wash and 4-6 times during the combination of the post rinse and acidified final rinse.
is
of a 1968 upgrade which combined two new silo-type tanks with existing
cylindrical tanks for milk and skim, the skim being the large tank in the
background. The valve group was a 4 x 6 matrix with supplemental valves
to support the four tanks with two receiving lines, a standardizing line
for skim, and supply milk to two HTST systems and a cold milk separator,
and skim or milk from two tanks to the positive displacement pump used
for volumetric control of standardizing transfers. This vintage
photograph includes a can rack, a cold milk separator, and a pipe wash
tank at the right.
Double-Tube Headers as a Valve Group Replacement
Whereas valve manifold assemblies provided the required automation,
they also created process 
dead-legs in which product would warm up, and which were not easily evacuated,
thus contributing to product loss. The double tube header was introduced
in the early 80's to overcome this problem, and to reduce capital cost
by reducing the numbers of air-operated valves required. The photo
at the left illustrates the use of five (5) 50,000 silo-type tanks to store
300,000 gallons of raw milk and make it available to three HTST systems
and a continuous standardization process by use a 4" OD x 2-1/2" ID double
tube header which:
- Provided raw milk to the three HTST's and a two tank batching system at up to 300 Gpm.
- Contained no dead-legs in which product could warm up.
- Could be fully evacuated in combination with the transfer line to a small buffer tank near the HTST's by a highly effective air-blow.
- Provided for any combination of two or three tanks to be connected for receiving and process supply, and required the manual change of a U-Bend connection approximately one every 2-1/2 to 3 hours.
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