CIP 'fail-safes'

Blog | 12 October 2018

As CIP is largely an automated cleaning process; modern CIP sets will integrate fail‐safe mechanisms to ensure the clean completes as expected, as well as providing protection to the operatives working in the area and product. As these fail‐safes are an integral part of the CIP process Holchem believes they should be periodically tested to ensure they react accordingly.

If we split these fail‐safes into four categories, namely; cleaning, product safety, health & safety, other and look in some more detail at what each fail‐safe is trying to achieve. Checking the function of a fail-safe needs to be carefully planned and done in conjunction with site engineers.

 

    Cleaning

The following are often used to control the CIP stage timers, each of the following should be at its set point before the CIP will begin the timer for that stage of the CIP. A good CIP should also pause or hold the CIP if any of the set points falls outside the designated parameters during the CIP stage.

  • Temperature and conductivity control and monitoring is generally carried out on the CIP return flow.
  • Flow rate is used at all stages of the CIP, however not all CIP sets use flow rate as a set point, especially older and more simplistic sets.
  • Some CIP sets will have signal feedback from the supply and scavenge pumps, this allows the CIP set to confirm that the correct pumps are running.

 

    Product Safety

Routing is carried out using different methods, namely: flow plates, mix proof valve matrix or simple swing bends. Feedback on routing is essential to ensure that cleaning chemical cannot be mixed with product.

  • Swing bends are the simplest form of routing solutions. The only way a CIP set knows where the bend is connected is if a proximity sensor is used.
  • Flow Plates are essentially more complex swing bends arrangements that are mounted on a panel, these allow multiple different connections to be made.
  • A mix proof valve assembly is commonly found on large and modern CIP installations; these do have feedback from the valve regarding its position. Customers should seek specific advice from the valve manufacturers about how these can be fail‐safe tested.

 

    Health & Safety

Routing fail-safes discussed above are also important for health and safety reasons. If a route is incorrectly set the cleaning solution could leave pipework at a flow plate / swing bend and cause harm to operatives working in the area. Additionally, proximity sensors on the CIP set manways and vessel manways are often present to protect the operative, these should pause the CIP when the connection is broken.

 

Other

Many other feedback routes on a CIP set exist such as low‐level and high‐level sensors on tanks; these sensors are generally used to control flow routing within the CIP set or pause the set if solutions are low. However, we should also be testing this as a failed high‐level probe could overflow the caustic tank causing a risk to operatives.

For further information on CIP please contact your local Holchem Technical Sales Consultant.