When looking at cleaning technology for clean-in-place (CIP) operations there are often just two questions on a prospective buyer’s lips: will it clean my tank and how much does it cost? Advancements in cleaning technology, however, now mean that it is possible to clean a customer’s tank and save them time and money in the process.
There are three basic types of technology:
- Static spray balls
- Single axis rotating
- Dual axis rotating
Each has their merits and it is through the correct selection of the type of equipment used that AWH is able to produce savings for its customers.
How Is A Vessel Cleaned?
To understand how selecting the correct equipment can save money we first need to understand the mechanics of how a vessel is cleaned. There are four inter-dependant factors that influence the result of a CIP cycle and in 1959 Dr Herbert Sinner combined these into what is now referred to as Sinner’s Circle.
Sinner identified the four key elements of cleaning to be:
- Mechanical action
Sinner recognised that by increasing one factor we can make savings on one or more of the remaining factors. When looking at any CIP cycle the most costly elements are generally time (lost production time), temperature (energy required to heat cleaning liquids) and the chemical or cleaning liquid itself (both in terms of the cost to buy the liquid but in today’s climate equally the cost of effluent treatment).
AWH’s cleaning technology focuses on the forth factor, mechanical action. This is the physical force used on the soiled area and with minimal investment in moving from one type of equipment to another it is possible to greatly increase productivity while reducing running costs considerably.
Static Spray Balls
The oldest, and currently most common, type of technology used is the static spray ball. With no moving parts and proper care it is potentially maintenance-free and, coupled with low investment costs, it is often the first choice of both vessel manufacturer and end user alike.
Operating at low pressure and with high flow requirements the cleaning function of a static spray ball is to produce points of impact on the vessel walls (where the jets from the holes hit) but this relies on the volume of liquid running down the sides of the tank for the majority of the clean. This leans the suitability of static spray balls more towards smaller vessels, as less overall volume of cleaning liquid is required to cover the tank walls, and easily removed soils (such as light liquids) as less mechanical action is required to remove them.
Single Axis Rotating Devices
As vessels increase in size or soiling becomes more difficult to remove we begin to look at single-axis rotating cleaners such as the AWH Tanko-S series.
While still operating at low pressure, single-axis rotating devices step up the level of mechanical action. The cleaning is carried out by a series of high-energy droplets, generated by fast rotation and precision cut slots, impacting instantly and repeatedly against the soiling on all surfaces.
Relating back to Sinner’s Circle, AWH is adding more energy to its cleaning, making it able to reduce both the amount of cleaning liquid needed (as it is used more efficiently) and also the length of time required for cleaning. This results in a direct cost saving for its customers.
AWH In Action
As an example of this, a study was carried out at one of the largest and most renowned German breweries, which had exchanged large static spray balls in 76 of its 700m3 fermentation vessels for Tanko-S50 rotating heads.
After extensive testing the company achieved a 38% reduction in cleaning (lost production) time, a 58% reduction in fresh water consumption (and so also 58% reduction in the amount of effluent it had to treat) as well as 39% reduction in caustic needed. In total this translated into a saving of €51.60 per tank, per clean. The payback period per tank by changing technology was under 10 cleaning cycles.
Multi-Axis Jet Cleaners
When considering larger tanks (typically >5m diameter) and heavy levels of soiling, often the most effective technology is multi-axis jet cleaners. This type of equipment is slow rotating and builds up its wash pattern over a certain period of time.
Although more costly from a CAPEX point of view than the previous technology types, the efficient use of the cleaning fluid and high level of mechanical action mean considerable savings on time and chemicals can be made. As an example, the Tanko-S50 will clean tanks up to 6m in diameter but at 3 bar requires 15m3/h flow to do so. The Tanko-MX125 multi-axis jet cleaner will clean the same size tank at a pressure of 5 bar but will only require 4m3/h to do so.
Having said this, it is not always the case that a multi-axis jet cleaner is the best solution. It is important to consider the nature of the soil you are trying to remove. A 5m-diameter tank with a light soil type may be cleaned quicker with a fast rotating single-axis cleaner (which instantly covers the surfaces) than a slower rotating multi-axis jet cleaner. It is important to identify the crossover in realised value between time taken and flow rate per hour required.Additional efficiencies
The Importance Of Jet Cleaner
Cleaning technology is most commonly operated/driven by the cleaning liquid flowing through it. Further efficiencies can be made by using an externally driven jet cleaner. These are usually driven by either an electric motor or by compressed air, such as the Tanko-JX range. As these jet cleaners are not relying on a certain volume of water to drive them flow rates are often much lower than conventional media driven jet cleaners. At 5 bar pressure the media-driven Tanko-MX125 with 4mm nozzles requires 4m3/h flow rate whereas comparably the externally driven Tanko-JX70 at the same pressure only requires 1.25m3/h.
In summary, selecting the correct cleaning technology is not always a straightforward process. The above are examples of the types of technology available to users but even within these three basic groups there are many variations on a theme, with each variation serving some specific condition. It is easy enough to choose a cleaner based on tank size and price but without taking into consideration the large number of other aspects of a cleaning application, the chances of selecting the best suited equipment are slim, and a golden opportunity to boost profits may be lost.
James Simmonds is with AWH