In this post we look at chemicals and chemical dosing. For best results, commercial dish washers are normally fitted with electronic dosing pumps to dispense the chemicals. Electronic chemical dosing pumps are programmed to allow dish washer detergent and rinse additive to be metered precisely and consistently into the correct wash cycle.
There are two methods of pumping detergent and rinse aid into a dish or glass washer:
- Via pumps located within the design of the washing machine itself – this is called “integral feed” and these are usually found on smaller capacity machines like cabinet glass washers. The pumps are pre-set by the machine manufacturer to try to accommodate most liquid chemicals available on the market. This often means that the pumps dose more chemical than required for optimum cleaning. The chemical manufacturer therefore only supplies the chemical and has no real input into dose levels.
- Via external dosing pumps which are usually provided Free-On-Loan by a reputable chemical manufacturer who will fit the dosing unit and set the dose rates for their specific chemicals and tailored to site requirements.
There are different types of electronic dosing systems available but most chemical suppliers use timed (or cyclic) dosing to get their products into the wash tanks in a controlled manner. Calculated chemical dose levels are pre-set by the chemical manufacturer to ensure the optimum concentration of chemical is used in each wash cycle, taking into account the amount of water in the wash tank and the volume of water added in the rinse cycle. The pumps are then calibrated and dose levels are programmed into the memory of the dosing unit to ensure that the correct amount of chemical detergent and rinse aid is added every time.
In future posts we will examine the pros and cons of timed dosing versus probe based dosing. In simple terms this type of dosing is based on the premise that a probe (located in the wash tank) detects the concentration of chemical available. If the concentration is too low, it “asks for more” and the pumps dose additional detergent to the required level. If the probe’s detection sensitivity is compromised (by being scaled up or enveloped in debris) it will falsely ask for more detergent when it is not required, meaning the machine asks for more than is required.
Although not an exhaustive list the following dosing unit manufacturers provide good quality equipment for all types of operations:
- Brightwell Dispensers (http://www.brightwell.co.uk/dishwash)
It is also worth considering setting up a preventative maintenance schedule with your chemical supplier, who will check, service and maintain chemical dosing units on a regular basis. A reputable chemical manufacturer will have an experienced team of service personnel who will routinely change pump heads and peristaltic tubing to ensure consistent dosing and will have access to qualified electrical engineers to fit and repair sophisticated dosing equipment.
The supplier should regularly conduct titration tests of the wash tank solution to ensure the correct chemical concentration levels are being maintained. They should also conduct temperature tests so that clients have hygienically clean and dry crockery, cutlery and glassware.
Wasted time is wasted money; therefore a prompt, reliable, efficient and professional engineering function from your chemical supplier is essential to maintain the operational efficiency of a commercial dishwashing operation. Customers need to know that if a breakdown is reported it is dealt with in a prompt and efficient manner to ensure as little downtime as possible for the operator.
For further information on the types of chemicals available for automatic dish and glass washing click here (http://www.rpadam.co.uk/products/dish-glass-washing/)
Both RP Adam and Arpal Gulf (following the completion of a new account installation) operate systems whereby a schedule of on-going service calls is automatically generated, thus offering customers unrivalled engineering support. Our technicians’ vehicles are well stocked with a wide variety of equipment, spares and tools, ensuring that work can be completed at the first visit. Our objective is always the same – complete the work first time, every time.
It should be noted that the automatic dish, glass and pot wash detergents that are automatically dosed into machines are almost all corrosive to the eyes and skin, so great care should be taken when handling these types of products and the appropriate eye and skin protection used. Please see our recent Golden Rules of COSHH post (http://www.thearpalgroupblog.com/chemicals-in-tea/)
As safety is our primary focus at all times, we will shortly be unveiling a brand new “Ultra-Safe” liquid dish and glass washing system…watch this space.
As usual, all feedback and comments are very welcome.
All five posts in our series on Auto Dish & Glass Washing can be found here.