The purpose of any programmable clean-in-place (CIP) system is to provide a consistent and repeatable wash cycle for the equipment washed. Consistent time, temperature, chemical, flow and pressures are critical for every cycle that is run.

Sheeting, the basic principle of tank washing, is accomplished using spray balls, spray disks or spray dishes. Sheeting involves spraying solution at the top of the vessel and allowing it to sheet down the dome, walls and across the floor of the tank to the outlet. This provides the mechanical action for removing soil from the vessel.

Impingement is the process used with spray balls to sheet a tank, but it is also designed to address areas inside the tank such as baffles and agitators that cannot be cleaned by sheeting alone. It may involve more than one spray ball or device. Such spray balls are designed for a specific piece of equipment and are not interchangeable. The flow follows the sidewall of the tank down to the floor and across the bottom to the outlet. Nothing that is put in the interior of the tank will be cleaned by this method.

Silo or tank doors, which we often see in dairies, swing into a tank to clean. This is not an effective method of cleaning because the door will not receive the sheeting action needed. The doors should be hand-cleaned as a part of the cleaning process. CIP doors, designed to keep the wash solution inside the tank, are the best way to limit the loss of the wash solution.

An enormous amount of calcium buildup makes the door more difficult to clean and provides harborage for bacteria.

Following are some practices to keep in mind:

  • All sanitation standard operating procedures (SSOP) and protocols for washing the door external to the tank must be followed. These protocols typically require manual cleaning and sanitizing of all components of a door as well as an inspection of all parts.
  • There should only be enough water in a tank to allow the outlet valve to be covered to prevent air into going to the CIP return pump.
  • Tank inlet and outlet valves must pulse during CIP or be disassembled and manually cleaned. Each time a product valve opens, product is on the valve stem and it is then pulled up through the O-ring area. The pulsing allows cleaning solution and sanitizer to enter.
  • Typically, use the shortest step in the program as the time value for pulsing a tank valve. That step is typically the sanitize step. The goal has to be, at least, pulse the inlet and outlet valve once during this step.
  • Line circuits are self-contained circuits with the valves pulsed by the automated controller. If there is hydraulic shock on a line circuit with valves, it is typically caused by the flow of the CIP solution behind the valve plug when it closes. To reduce hydraulic shock, always ensure the path of the CIP solution is initiated under valves first and then back over them.
  • Plug valves in a line cannot be washed merely by loosening the valve and allowing water to leak out. They must be removed, cleaned, inspected for damage, sanitized and re-installed.

As a training aid, keep a damaged piece of equipment to use for “show and tell.”

COP and its pitfalls

Unlike CIP systems, COP (clean-out-of-place) units are designed to wash equipment by placing it in a hot chemical solution. The components are washed through the process of agitation in the tank. Properly equipped COP tanks will have a chart recorder that provides a record of the time and temperature of the wash cycle. The operator should initial the chart and place the chemical titration readings on the chart for each cycle.

Following are some practices to keep in mind:

  • All equipment placed in a COP tank must be pre-rinsed or pre-cleaned if heavy soil is present. Otherwise, it will overload the chemical and be re-deposited on equipment being cleaned.
  • All equipment placed in a COP tank must be totally disassembled and placed in a manner to allow flow through or around.
  • Heavy items should not be dropped on fragile, small or delicate items. Teflon should be placed in COP baskets to prevent damage.
  • O-rings may be strung on a piece of stainless steel welding rod made into a hoop and hung in the COP tank.
  • Large items that cannot be fully submerged in the COP tank should be cleaned by hand, as they may block the circulation ports and will inhibit agitation.

Remember: No Turbulence = No Cleaning.   

For More Information

 Learn more about H. Randolph Inc.’s training programs, products and technical expertise by visiting the company website at Sign up for the Pasteurization Workshop, Dec. 7 to 10. To register, or for additional information, contact Kristy Clark at 205-595-6455, or email