CIP: The Industrial-Grade Dishwasher

There is an episode of the ’90s hit comedy show Home Improvement that I think of every time I pull out dirty dishes from the dishwasher at home. You know, after they’ve supposedly been cleaned…it’s the peanut butter spoons, the charred grit burnt onto the bottom of the pan, the baked on meatloaf, etc.…In this episode, Tim “The Toolman” Taylor observes his wife pre-rinsing the dishes prior to putting them into the dishwasher. This was an action The Toolman couldn’t wrap his head around. After all to Tim’s point—isn’t that the purpose of the dishwasher? What proceeded from there is Tim’s extreme attempt to “beef-up” the dishwasher with extra horsepower to handle those sticky situations. And while humorous, Tim’s goal to address this issue is a serious matter within the food and beverage industry. Just ask any dairy farmer, production supervisor, sanitation technician, process engineer, or quality manager what their solution to ensuring food safety is in their industry and they’ll point to the clean-in-place (CIP) system, an industrial-grade dishwasher sure to gain the approving nod, and primitive grunt “ooo, ooo, ooo…” from Tim The Toolman himself.

CIP systems are process systems tasked with the objective to clean the equipment used in the receiving, delivery, distribution, processing, and manufacturing of food and beverage products. The systems themselves are an arrangement of tanks, valves, pumps, heat exchangers, and associated instrumentation such as temperature/level/pressure/conductivity transmitters, flowmeters, chart recorders, and automated control systems. These components are traditionally assembled onto a prefabricated stainless steel skid, giving way to the commonly used term of CIP skid.

The primary advantage of CIP systems is they relieve the burden of having to tear down equipment to be cleaned. Instead of running ingredients through the process system, as would be done while in production, the line and/or equipment is connected to the CIP skid which runs the cleaning solution through the process. Therefore, they are used to clean virtually everything, including the pipes, valves, fillers, homogenizers, pasteurizers, tanker trucks, and all other associated equipment.

To gain a better understanding of these industrial-grade dishwashers, here are the answers to frequently asked CIP questions.

Q: Are CIP systems automated?

A: Yes, but they weren’t always this way. Early CIP systems consisted of a CIP skid with wash and rinse tanks like they do today. However, those early systems were independent islands of control that lacked automation and integration with the systems being cleaned. Once upon a time, device sequencing was made possible with rotary cam switches and other electro-mechanical devices. These mechanical sequencers limited control capabilities to the skid devices only. Field devices relied on isolated relay valve pulsing that could never be fully synchronized with the skid sequence—resulting in improper and inefficient cleaning.

For example, due to the disconnect between skid and field device sequencing, water-hammer would result. This occurs when the skid’s supply pump is running at full speed and the field routing valves close at the wrong time, causing liquid in the line to abruptly slam like a “hammer.” Water-hammering is detrimental to valve seals and pipe welds. Additionally, because of a lack of instrumentation and monitoring, often length of time for a run had to be extended just to ensure the circuit was cleaned.

Some chemical engineers and process engineers still see the skid and field as two separate entities. But that limits the advantages a fully automated system can provide.

Automated system advantages include:

• Integrated skid and field device sequencing, resulting in coordinated and optimized routing paths (the elimination of water-hammer);
• Use of valve position feedbacks to generate routing path faults to halt the CIP process;
• Accurate flow monitoring using flow meters instead of flow switches;
• Tracking total water usage;
• Ensuring proper supply and return temperatures are achieved;
• Conductivity monitoring to verify desired chemical strengths are satisfied;
• Level and pressure monitoring;
• Allergen-wash categorization; and
• Electronic records, reporting, alarm/fault logs, and time/date stamping.