In the Beginning (1950-1960) 

Before the development of recirculation cleaning, now referred to as CIP (Clean-In-Place),  in the early 1950's, all dairy processing equipment  was manually cleaned after each period of use, often several times daily.  Piping systems were assembled by production personnel and consisted of various lengths of stainless steel or tinned copper tubing less than 10 feet in length, and nickel alloy fittings including elbows, tees, caps (end plugs) and 2-way or 3-way plug valves, assembled with paper gaskets.  Tanks were limited to eight feet in diameter as the height an average person could reach to scrub with an 18 inch brush.  Cleaning operations were accomplished by production personnel during the day shifts, and (in larger dairies) on the night shift these important operations were generally delegated to persons most recently hired, given little training, and minimal (if any) supervision.  

The hundreds of pieces which comprised the sanitary piping system were washed by hand, with a bucket and brush, or in a Pipe Wash Tank with a powered brush as shown in the photo to the right found in a Dairy Sanitation Handbook published by Klenzade Products Company in the 1950's.  Following washing and rinsing the parts were stored on racks or carts between periods of use.  Other sections of the handbook described procedures for cleaning other equipment, including cylindrical tanks shown in the photo to the left . The first CIP cleaning was done by using available vessels as the solution tank, portable pumps, and hoses to connect the equipment and piping into circuits for recirculation of flush, wash and rinse solutions.  Heating was accomplished by inserting a low pressure steam hose into the solution tank and temperature was controlled by the "finger test", or a thermometer if one was available.  The early CIP circuits consisted of only the longer pipelines in the facility, such as the receiving line to the Raw Milk tanks, or a supply line to the pasteurizers, and all shorter lines, connections to equipment, and fittings and valves were manually cleaned, as before.  

The efficacy of CIP cleaning was dependent on the control of Time, Temperature` and Concentration (of the cleaning chemicals) and Automation was applied to improve control of the process in 1953-54 in a small Ohio dairy then converting from batch to HTST (High-Temperature Short-Time)  pasteurization. The Hot Water Set for the HTST system center below  was fabricated of stainless steel using sanitary pumps and valves and an injection steam mixer.  Peristaltic alkali and acid pumps were added and this system was designed as perhaps the first example of "split-flow" CIP of the heat exchanger, with all raw piping in series with the raw regenerator and final heater and all pasteurized piping in series with the pasteurized regenerator and final cooler, to maintain pressures within the plate gaskets limitations at the required flow of 25 Gpm in the 1-1/2" piping. The green lines were converted to JP and clamp-type CIP construction. A single circuit thus cleaned all raw milk piping, all pasteurized milk piping, and the HTST heat exchanger, holding tube, flow diversion valve, and homogenizer. All red lines were removed for manual cleaning.  The plug valves were manually cleaned before CIP.  Control was via a Taylor Flexo-Timer adapted from the rubber industry.  The 2-2000 gallons cylindrical tanks  at the upper left were subsequently used as test vessels during the development of the first permanently installed fixed ball sprays.  See PUBLICATIONS on this site.  

A second Taylor Flexo-Timer was made available to the Ohio State University Department of Dairy Technology and was used to control a demonstration of Automated CIP at the 1954 Dairy Conference.  During 1955-56 this controller was combined with  a Farm CIP Tank and other components to develop the apparatus shown at the right to evaluate CIP cleanable air-operated valves and also ten (10) different types of CIP joint and/or gaskets then on the market. See PUBLICATIONS on this site.  The ten different CIP joints, modifications of bevel seat joints and special gaskets to use in standard bevel seat joints are shown in the photo to the left.  Subsequent experience with installation of CIP cleaned piping revealed the need to provide adequate support to assure maintenance of alignment and pitch, and this was best accomplished by installing new piping, rather than modifying existing materials.  And, the strong chemicals used for CIP transferred copper from nickel alloy fittings to stainless steel surfaces throughout the circuit, as a stain.  Slowly it was recognized that a CIP cleaned piping system must be constructed entirely of stainless steel.  

During that period of time when the air-operated valve was being re-designed to be CIPable, successful efforts to clean storage and transportation  tankers with permanently installed spray devices were also underway.  The photo to the left shows an early spray developed to meet criteria established by the Ohio Department of Health and the USPHS.  These sprays were developed and evaluated in the same facility in which the first automated CIP system was installed, by installing a second system so as to be able to clean tankers and tanks when the HTST was still operating on milk.  See PUBLICATIONS on this site.  

The first commercially available CIP Systems were  marketed in 1958, and from the very beginning, two different modes of operations included Single-Use systems  represented by the photo on the right, and multi-tank re-use systems shown in the  photo to the left. The Single-Use systems were designed to make up   the smallest possible volume of solution required, use it once and discard it whereas the re-use systems used a batch of solution for a day or more, spiking it with added water and chemical periodically.  The single tank system in the vintage 1968 photo to the right was widely used in both the USA and abroad.  In its standard  form, with a 60 gallon tank, 2" valves, and a 7-1/2HP 3450 Rpm pump, it was capable of cleaning the largest tanks and longest CIP piping circuits in use when supplied with adequate water.  The wall mounted chemical pumps supplied a chelated caustic, a water conditioner, and an acid to the CIP unit and to HTST constant level tanks.  Sodium Hypochlorite and an Iodophor sanitizer were supplied by diaphragm pumps on the wall to the right.  These five chemical products, supplied under automatic control in various combinations, sequences and concentrations, met all requirements for cleaning and sanitizing any dairy or food process. Central CIP Systems of this type must be located near the center of the greatest CIP loads, normally tankers and raw tanks, to minimize water, time and chemical requirements and capital cost.  

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