LHS are leaders in the design and manufacture of Cleaning In Place systems for all types of process industries. We can offer any type of system from manually operated modules to fully automated and integrated systems capable of cleaning a variety of tanks and pipework within a process plant. We offer a full service including preliminary technical advice, module and pipework design, manufacturing, installation and control systems.
All our systems are designed in a modular form to allow cost effective future expansion of the Cleaning In Place system. In purchasing an LHS system the customer can be confident that their requirements will be understood, advice will be given in an impartial manner and construction of the module carried out to the highest standards. Our professional and highly skilled installation technicians will then ensure that the system meets all the customers objectives.
What Is CIP (Cleaning In Place)
CIP stands for 'Cleaning In Place' and is widely used in all types of process industries. It has been developed from the requirement that process industry plant must be used efficiently to gain maximum cost benefits. CIP covers a variety of areas but its main purpose is to remove solids and bacteria from vessels and pipework in the food and drinks processing industries.
Obviously the task of dismantling process plant for cleaning would be time consuming and where tank entry is required, a dangerous one if it were feasible at all. CIP allows process plant and pipework to be cleaned between process runs without the requirement to dismantle or enter the equipment. It can be carried out with automated or manual systems and is a reliable and repeatable process that meets the stringent hygiene regulations especially prevalent in the food, drink and pharmaceutical industries.
The majority of cleaning and sterilizing liquids used in CIP systems are alkali or acid based and the CIP system will allow accurate dosing of the concentrated cleaning agent, normally into water, to give a low strength solution suitable for cleaning process plant. This solution is then used within the plant to clean and if necessary sterilize the system prior to the next production run.
Benefits Of Cleaning In Place
Cleaning In Place has many benefits to the end user, some of the main reasons for implementing Cleaning In Place are
Safety; operators are not required to enter plant to clean it
Difficult to access areas can be cleaned
Production down time between product runs is minimised
Cleaning costs can be reduced substantially by recycling cleaning solutions
Water consumption is reduced as cleaning cycles are designed to use the optimum quantity of water
The cleaning system can be fully automated therefore reducing labour requirements
Automated CIP systems can give guaranteed and repeatable quality assurance
Automated CIP systems can provide full data logging for quality assurance requirements
Hazardous cleaning materials do not need to be handled by operators
Use of cleaning materials is more effectively controlled using a CIP system
Different Types Of Cleaning In Place Systems
Single Pass systems.
In a single pass system new cleaning solution is introduced to the plant to be cleaned and then disposed to drain. In most cases a single pass system would start with a pre-rinse to remove as much soiling as possible. The detergent clean and a final rinse would follow this.
In a recirculation system the cleaning solution is made up in an external tank then introduced to the plant to be cleaned. It is recirculated and topped up as required until the cleaning cycle is complete. When the detergent clean is complete it is then normal to carry out a final rinse.
In general recirculation systems use less water & cleaning detergents but require greater capital outlay and in some circumstances may be unsuitable due to cross contamination from one process to another. We can if required calculate usage for these types compared to an existing system to demonstrate potential cost savings and pay back periods.
The first design consideration for a Cleaning In Place system is the cleaning requirement for each process vessel. Factors to be considered can include the size of the process vessels; standard of cleaning required, the available cleaning time, the type of cleaning medium, and whether recycled detergent can be used.
With this information cleaning heads can be selected to meet the requirements described above. This then allows pumps to be selected to match the flow rates required for the heads and the type of cleaning material being used. The module size and configuration can also be calculated from this information.
The process diagram below shows an example of a three-tank Cleaning In Place system. There are three holding tanks, which are mounted in a stainless steel bund. The tanks are normally a bulk caustic tank, dilute detergent tank and fresh water tank. The capacity of each tank is calculated according to the initial system requirements described above. In the case of the bulk cleaning liquid tank the customer may also specify the tank size to suit optimum delivery quantities. Bulk cleaning liquid is normally delivered to a connection point outside the process plant and pumped to the storage tank by the delivery vehicle. Heating can be specified for the bulk cleaning liquid tank depending on the properties of the cleaning agent. Lagging and cladding can also be fitted for improved energy efficiency.
The bulk cleaning liquid is pumped to the detergent tank before each cleaning cycle along with water to make up a batch of detergent. The detergent is normally more effective at a higher temperature. If this is the case it would then be pumped through a plate heat exchanger to bring it to the required temperature. The system shown below allows the detergent to be recirculated through the heat exchanger until it reaches the optimum temperature. The heat exchanger would be designed to suit the temperature drop in a recirculation system.
The strength of the cleaning detergent is normally stated as a percentage of the cleaning agent being used (usually with water). In the majority of cases this is between 1 and 10% by volume. There are various methods of achieving the required strength but the two main methods are a) using a positive discharge pump shown in the diagram for a calculated time and b) using a conductivity probe to read the strength of the detergent (this is only effective with alkalis, not acids). The conductivity probe is located in the recirculation/scavenge line.
When the detergent is ready for use the process vessel to be cleaned is selected and the system will run through a cleaning cycle. A pre rinse will be carried out first using water from the rinse water tank. The detergent will then be cycled through the process system before being returned to the detergent tank. A final rinse will then be carried out again using water from the rinse water tank.
Depending on customer requirements this detergent can then be re-used, bulk cleaning liquid being added as necessary to maintain the required cleaning strength by use of the previously mentioned conductivity probe. It may be undesirable in some cases to re-use detergent in another part of the process system due to cross contamination. If this were the case the detergent would be dumped to drain after use. If it is not practical to discharge the detergent to drain as an alkali/acid then we can install a system to neutralise the solution.
If the CIP system is being used to clean a number of vessels as shown in the diagram below then to safeguard the vessels/plant not being cleaned it is necessary to have a safe valve or similar system. The double seat (block and bleed) valves shown have a chamber between two valve seats. When the valve is open liquid will flow through. When it is closed the chamber between the two valve seats has an open part so that any cleaning liquid passing through the inlet seat will drain out of the chamber and cannot cause contamination at the outlet side of the valve.
Another method of ensuring that there is no contamination of other process lines during cleaning is to use a swing bend flow plate system where a direct connection is made from the CIP feed to the pipeline feeding the process plant to be cleaned. Proximity switches may be used with the swing bend to ensure that the correct path is selected before valves can be opened and cleaning started.
The control of Cleaning In Place systems can vary from simple manual operation to fully integrated PLC controls with touch screen operator interfaces. The design of the control system will vary according to the process being cleaned and the customers requirements. We can provide a full service to suit any customer. Stand-alone or fully integrated controllers can be provided depending on the customers needs.
There are a variety of different spray devices available the selection of which is dependant on a variety of factors including capital and running costs, supply pressure, cleaning time, vessel size, spray pattern and type of soiling. Some of the most common can be seen below.
Fixed spray balls
Fixed spray balls are low cost, low maintenance. They operate at low pressure (2 bar) but use high volumes of water. Cleaning times are long and range tends to be about 2 - 3 metres. These items have a fixed spray pattern and are not really suitable when the vessel is badly soiled or has material baked on.
Rotary Cleaning Heads for Smaller Vessels Up To 4m diameter
Rotary cleaning heads are higher cost than spray balls. They operate at higher pressure but use a lower volume of water. They are normally more effective over shorter periods so reducing down time of plant and lowering detergent costs. They can be supplied with a variety of different spray patterns, some of the common ones are shown in the diagram to the right.
Rotary Cleaning Heads For Larger Vessels
These heads are high-pressure units with directional jets offering fast cleaning times. Higher capital costs are involved but fully indexed coverage at long range using low volumes of water and detergent will compensate for this.
This Diagram shows some of the common spray patterns available. There are many more patterns to suit individual requirements and in the case of Large Rotary Cleaning Heads specific areas of the vessel can be avoided if necessary.
The illustrations above cover cleaning heads, which may be used on most projects, but there are applications where specific cleaning requirements mean more specialist heads. If there is a cleaning situation, which is causing problems, please contact us and we will be pleased to help.