Unit 16 - Plant Cleaning In Place cleaning systems Flashcards
What is CIP?
Is the circulation of detergents. water rinses and sterilant through fixed plant without dismantling.
To achieve this, tanks have to be fitted with spray balls/heads and pipework has to be linked into a “ring” main
What are the features of a CIP system to be considered?
The CIP system could be a “recovery” or a “total loss” system.
Tank CIP choice of spray head
Flow rates, delivery and return
Choice of cleaning/sterilising materials.
Automation & monitoring
Running costs
Describe a recovery CIP system.
A recovery CIP system consists of tanks where supplies of detergent and sterilant are held at the required concentration for use.
Cleaning fluids are delivered from the tanks and returned to them. Detergent and sterilant strength is maintained in the tank.
What is the CIP cleaning & Sterilising standard programme?
A rinse to remove as much soil as possible and to flush this to drain.
A detergent recirculation to clean the plant
A rinse to remove traces of detergent
A sterilisation to destroy any remaining micro-organisms (if required)
A final rinse if it is decided that no sterilant should remain in the plant.
Compare Recovery vs Total Loss Systems?
Recovery System
Capital costs are higher because of the need for large tanks
Running costs are lower because all chemicals are recovered
Only able to clean one type of plant from a cleaning unit
Simple to operate.
Total Loss System
Lower capital cost
Higher running costs
One cleaning unit can clean different types of plants
Complex control system relying on detergent/sterilant strength sensors.
What are the two main types of spray head?
The fixed spray head
The rotating spray head
Describe Fixed spray ball
This uses large volumes of cleaning liquid at low pressure.
relies on the cleaning liquid flowing over the surface of the tank, therefore the whole surface must be covered.
Positioning of the head must ensure full coverage.
Burst rinsing is effective because the liquid finds new routes to flow down with each burst.
Attention needs to be paid to tank drainage/scavenge because of the large volume of cleaning liquid. The base of a poorly drained tank is not cleaned because the cleaning liquid does not flow over the surface at a sufficient speed.
SB are quite cheap and easy to maintain but can block up especially if cleaning liquid is unfiltered.
What dictates the type of spray device?
Dimension of vessel.
Spray balls shower the entire surface all the time the pump is operational by directing impact flow of fluid to the area. Fluid runs down the side of the walls of the vessel in a continuous curtain.
Describe a rotating spray head.
This is a mechanically driven head that rotates to direct a high pressure jet to the tank surface, usually in a pattern to ensure that the entire surface is jetted. This principle means that it takes a specific time to complete the pattern and cover all surfaces.
Rotating spray cleaners require a high pressure to direct the fluid onto the surface of the vessel, the fluid flows down the rest of the surface cleaning on it’s way.
The rotating jets have a higher impact force on the surface exerting greater mechanical effect on the soil or scale, than the flooding low pressure system applied on fixed spray balls.
This spray head can use colder and or less aggressive detergent than the fixed head.
RPH are expensive and are made up of moving parts, there is more wear and tear, they are often fitted with rotation detectors because a stationary head will only clean a small amount of the tank.
What are the advantages of Complex CIP systems being controlled manually?
A programme can be deigned and set when the plant is commissioned to maximise cleaning and this will be consistently adhered to.
Detergent and sterilant strengths can be optimised
A cleaning cycle can run unsupervised
Automated recording of cycle times, detergent strengths and temps by the monitoring equipment is available.
Cleaning can be held up if a problem is detected
Sensors can detect detergent/sterilant strength on the return line and direct the return to tank or drain saving chemical costs.
What items in the CIP system are automated?
Inlet & outlet valves of detergent/ sterilant tanks
Delivery pump
Rinse water and drain valves
Detergent/ sterilant strength detection and tank top up from bulk supplies
Detergent/ sterilant strength detection on the return line.
Effective cleaning is the result of a combination of what four factors?
Time - how long is the cleaning agent/detergent in contact with the plant?
Temperature- How hot is the cleaning agent/detergent?
Chemical activity - How strong/effective is the cleaning agent/detergent?
Physical activity - How vigorously is the cleaning agent/detergent applied to the plant?
Plant design needs to take what concepts into consideration?
The plant capacity needs to be large enough to allow time for cleaning.
The parts of the plant where very high standards of hygiene and sterility are required should be capable of being cleaned hot
The materials of construction should be capable of withstanding strong detergents like caustic soda.
The plant design should either allow access for manual cleaning or more commonly ensure that detergent can flow over the surface at the speed required to give a vigorous clean.
What are plant features that allow high temperature cleaning?
Strong construction, for example thick walls to a vessel.
The presence of a pressure relief valve, which must be regularly tested.
Vacuum relief system, to prevent the collapse of the vessel due to the very low pressures that will occur if the vessel cools quickly.
What are some issues of construction materials?
Caustic soda will dissolve aluminium
Chlorine is a very strong oxidising agent and will corrode most metals
Acids will seriously damage concrete
Dilute sulphuric acid corrodes many grades of stainless steel.
Hoses and rubber seals, for example plate heat exchanger gaskets can pick up taints from sterilising agents.
