Automatic Tank Cleaning
Cleaning the tank can be accomplished through three methods: automatic tank washer, tank washer with a spray ball, and mechanical (or rotary jet type) tank washer. The spray ball type tank washer sprays the cleaning fluid onto the tank wall or the upper part of the tank, allowing the cleaning fluid to flow down the tank walls. Generally, the cleaning solution forms a film on the tank wall, so the mechanical washing effect is minimal, and the washing effect mainly relies on the chemical effect of the cleaning agent (such as dissolution).
Using mechanical tank washers can enhance the mechanical rinsing effect. The cleaning solution sprayed by the mechanical tank washer can directly spray each point of the tank surface, achieving an impulse spray wash. The special spray ball type tank washer has a radius of action of up to 5m and a washing liquid flow rate of 60m3/h. The general spray ball type tank washer has a radius of action of about 2m, a washing liquid flow rate of about 12m3/h, and the nozzle outlet pressure should be 2-3MPa.
For vertical tanks and pressure measurement points at the outlet of the washing pump, it is necessary to consider not only the pressure loss caused by pipeline resistance but also the impact of cleaning pressure height. When the pressure is too low, the radius of action of the tank washer is small, the flow is insufficient, and the spray cleaning fluid cannot cover the tank walls. When the pressure is too high, the cleaning fluid will form a mist, preventing the formation of a downward flow of water film along the tank wall or causing the spray cleaning fluid to bounce back, thus reducing the washing effect.
When the equipment being cleaned is dirty and the tank diameter is large (d > 2m), mechanical tank washers are generally used. By increasing the outlet pressure of the tank washer (0.7MPa), the washing radius and cleaning intensity can be increased. Compared to spray ball type tank washers, mechanical tank washers can use a lower flow rate of cleaning fluid.
The key to pipeline washing is maximizing the mechanical role to improve the washing effect. The flow state has a significant impact on the washing effect when cleaning pipelines. When the flow rate is slow, the fluid in the pipe is prone to stratification, and the flow rate of the fluid in the pipe gradually slows down from the center to the edge, making it difficult to wash away dirt. Therefore, higher flow rates should be used during pipeline cleaning to create vortexes and turbulence in the pipeline.
When cleaning with cold cleaning fluid, different pipe diameters require different flow rates of washing fluid in the pipe to achieve a good washing effect.
When cleaning with hot cleaning fluid, the flow rate of the cleaning fluid in the pipe should be maintained at 1-1.5m/s. Special attention should be paid to the cleaning of CO2 and compressed air pipelines and their accessories, which should be performed at least five times a year.
Heat Exchanger Cleaning
Heat exchanger cleaning follows the same principles as pipeline cleaning. The medium inside a heat exchanger is turbulent during normal operation. To achieve good cleaning effects, the design flow should be 20%-30% higher than the flow rate of the cleaning fluid.
Equipment Parts and Machine Evolution Washing
There is no standardized cleaning method for equipment machine parts and machine evolution. It should be done according to the equipment’s cleaning instructions. When using hot cleaning fluid to soak equipment (such as filters), positive pressure should be maintained in the tank to prevent outside air from entering when the cleaning fluid cools.
The washing temperature and cleaning time for hoses should be determined according to the technical requirements of the product. Generally, hoses can only be cleaned with alkaline detergent. Oxidizing acidic detergents and disinfectants will accelerate hose aging, causing the inner surface of the hose to become rough and develop fine cracks.
This makes hose cleaning more challenging, so the use of hoses should be minimized. The service life of a hose is generally 3-4 years, and expired hoses should be replaced promptly.
Cleaning Tank Top Components
The cleaning of cone-bottom tank roof parts (such as safety valves and vacuum valves) is a weak link in brewery sanitary management and should be taken seriously. These parts should be cleaned during the tank cleaning process. The appropriate cleaning method can be selected based on the characteristics of the components and the design of the installation site.
The ultimate goal of cleaning and sterilization is to ensure that all parts and equipment in contact with the product are free of deposits and surviving microorganisms, thus guaranteeing the hygiene of beer production. Sanitary inspection is an important quality control tool for beer, so emblematic organism inspection and sanitary supervision should be carried out at all relevant production stages.