Importance of Quality Tanks for Dairy Processing

High quality stainless steel tanks are of paramount importance to the dairy industry. Poor quality vessels, or those not manufactured to the correct specifications, can significantly hinder your hygiene efforts.

It is extremely important that Raw Milk silos are properly cleaned between uses. Cleaning removes any solids that form on tank surfaces once the tank is emptied. You also need to sanitise tanks to kill bacteria or micro-organisms immediately before the next filling.

Under Standard 4.2.4 of the Food Standards Australia New Zealand (FSANZ), all dairy farms must have a food safety programme that is documented. This includes “control measures to manage the hazards arising from the design, construction, maintenance and operation of premises and equipment”.

It is important, therefore, to start with the right stainless steel tank so you can carry out effective cleaning and sanitisation. At A&G Engineering, our unique automated plasma TIG welding systems ensure the highest calibre of quality and repeatability of welded vessels available in the market.  We also use in-house programmes developed over many years working with industry to cover a critical areas of the vessel designs; including structural, venting, Clean-in-Place (CIP), insulation, passivation and polishing.

Clean-in-place (CIP) systems

The CIP system is the most commonly used automated cleaning system within the dairy industry, allowing for tanks, plant equipment and pipes to be cleaned without the need to dismantle equipment. CIP systems clean much faster, and the process is less labour intensive.

CIP systems rely on an internal spray device such as a rotating cleaning nozzle or a fixed spray ball. Should either the nozzle or the spray ball be incorrectly sized, then there could be too little flow, or too much, which means the cleaning process will be ineffective and could result in contamination of the subsequent milk batch.

Intrinsic to CIP operations is the combination of time/temperature, and as a result of this combination, the critical design and sizing of the vent. If the vent isn’t designed correctly to keep air flow in the correct range, then the vessel will be subject to pressure and/or vacuum. Either of these scenarios could result in the collapse of the dairy tank.

A&G have available a varied range of CIP options available, to suit every individual circumstance or application.

Importance of correct agitation

Proper agitation is essential for the product for temperature consistency, homogeneity, correct mixing, consistency and to ensure the products meet their required specifications. Correct agitation is largely reliant on the design of the agitator impeller combined with speed, size and profile, which must be a simple design for ease of cleaning, but of the correct width for the size of the tank and viscosity of the dairy product.

A&G works closely with you to ensure that the correct agitation solution for vessels is implemented.

Internal welds in stainless steel tanks for dairy

Some customers specify a ‘grit finish’ as a specification for a polished weld surface. The main challenge here is you can use the same ‘grit’ and end up with a large variation of surface finishes. At A&G, we always specify and measure the polished surface in Micron. This gives a known result with a measurable finish.

When you’re specifying your stainless steel tank, what finish should you specify for weld surfaces in the interior of your tank?

The accepted dairy internal finish for welds is 1.0Ra (Micron). This standard ensures a hygienic and easy-to-clean surface that is acceptable to the industry.

At A&G, we are able to meet and evidence internal weld finishes of 1.0Ra to the customer’s satisfaction in the dairy industry, through our thorough Quality Assurance regime, and our unique automated tank polishing system.

Steel grade for stainless steel dairy tanks

We select materials and grade that best suits the customer, largely by assessing and determining the product, the CIP system and the temperature range of the product or cleaning cycles.

For more information on dairy tanks

If you have any questions about stainless steel tanks for the dairy industry, please call our knowledgeable team on (02) 6964 3422 or email us at We’re here to help.