Retro Fit Tank Wash

Saving water in tank cleaning - is there were a simple way to reduce water and maintain or improve cleaning at the same time?

The water used in tank cleaning processes can be a considerable cost for a business. Many food industries, like dairy processing, need to ensure strict hygiene standards are maintained and their waste product tends to have a high BOD (biological oxygen demand) as well as a high COD (chemical oxygen demand) through the necessary use of caustics. This means the treatment of waste water is also costly.

Water saving is thus a key concern for such businesses. But food safety is an even bigger concern. Using lots of water and chemicals will ensure hygiene is maintained. In a competition between the risk of poor hygiene and cost savings through lower water usage food safety will always win. The risk analysis is simple, one contaminated batch and health scare can sink an entire company. There is simply no contest in which is most important. But what if there were a simple way to reduce water and maintain or improve cleaning at the same time?

It’s not magic it’s physics!

The most widely used tank cleaning heads are spray balls. They are simple devices that spray liquid through multiple small holes to form mini jets. The jets squirt out in all directions hitting the tank walls causing the liquid to cascade down. As the liquid moves the solvent properties of the water or caustics used dissolve the residue and carry it away. Spray balls are simple, tried and tested, cheap but also very water inefficient.

Impact cleaning delivers powerful jets of water to the tank wall. These jets explode outwards dislodging residue by the mechanical action / kinetic force rather than by the solvent properties of the fluid. Of course the fluid will then run down the tank wall and give solvent based cleaning action as well. This style of cleaner is far more water efficient and can, in some cases, deliver the same amount of cleaning using only 5% of the water a spray ball would. Typical “real world” water saving range between 50% and 90% depending on the application.

This is not magic. It is simple physics. Most of the internal energy contained within the pumped cleaning fluid is wasted in spray balls. It is used to break apart the fluid into many micro jets. Each of these jets is itself rather turbulent and of poor integrity meaning further kinetic energy is wasted. By the time the micro jet meets the tank wall it has almost no impact left. In contrast jet cleaners focus the fluid into 2 or 4 bigger jets using nozzles designed to ensure a laminar, coherent jet that retains as much of its energy as possible. The result is a high impact jet that dissipates kinetic energy in all directions as it hits the wall. This means less water can deliver far more cleaning power.

Why swap?

There are several good reasons to swap to this more efficient tank cleaning technology.

• The bottom line
  Water costs money. The investment in jet cleaning technology can often pay for itself in a matter of months. Over the course of years the savings can be huge.
• Image
  Water saving and other green initiatives are of importance to the public. Many companies are realising that having good green credentials is actually important to their PR efforts. If you can demonstrate significant efficiency gains have been made then it is news worthy. As we shall see below this might actually be one of the easiest PR wins a company can make.
• It is the right thing to do
  We may well all be a bit bored of the “save the planet” / “go green” mantra bombarding us from the mouths of every Hollywood celeb and other saintly do-gooder over the last few decades but this does not stop the message from being correct. We all need to do our bit and that includes industry, one process at a time. Sure, making tank cleaning more efficient is not going to reverse global warming and save the polar bears on its own but it is, nonetheless, one of the many thousands of littles steps required.

What’s stopping you?

There are commonly three main concerns engineers have about swapping.

• I need to change my CIP system
  This is might have been true in the past but it is not today. The new fast cycle jet cleaners on the market will run at low pressures and on similar pump duties to existing spray balls. There is no need to change the system in most cases. The new smaller jet cleaners will also fit through narrow tank openings and can use the same pipework. It can be as simple as unthreading / clipping the existing spray ball and then connecting the new cleaning head.
• I can’t risk my cleaning
  Obviously this is a legitimate thing to be concerned about. A certain amount of paranoia around food safety is a very good thing to have. But cleaning will almost certainly be improved by swapping your existing spray balls for jet cleaners. Jet cleaners have been used for decades by large food and beverage manufactures, they are tried and tested bits of kit.
• Jet cleaners are expensive
  Again this myth may have been true in the past but costs have come down considerably. Whilst they are more expensive that spray balls the water savings and potential to reduce heat and / or chemicals as well means that the return on investment can be reaped in only a few months. This coupled with the fact that it is no longer necessary to change pipework/pumps and systems means the investment is limited to the cleaning head itself. As such a jet cleaner should offer e very rapid return on investment perhaps measured only in months or weeks.

The next steps

Swapping from spray balls to rotary jet cleaners might be one of those rare projects that is easy to implement, not very costly, low risk and can pay high dividends. It’s a bit like putting a water saving shower heads in the bathroom shower. Once it’s installed you wonder why on earth you didn’t it sooner. The shower quality is no different, in fact it actually feels more effective, and you are using less water. The whole thing took 5 minutes to put in and now you are doing the mental calculations on how much water you have wasted over the last decade. The same is probably true, but on a bigger scale, in your tank cleaning process if you are still using spray balls. So perhaps it’s time to make the change, if not for the planet then for the bottom line of your business?