Combined Approach Prevents Contamination

The safety of key products, such as food, drink, pharmaceuticals and toiletries, depends on the management and control of a wide range of factors throughout the whole supply chain, from raw material and ingredient production and procurement, through processing and packaging, to storage, distribution and even post-purchase consumer behaviour.

The use of HACCP (Hazard Analysis and Critical Control Point) analysis facilitates this approach, but it is also important that, where necessary, equipment is designed and manufactured to prevent possible contamination, for example between product and service fluid during pasteurisation or sterilisation.

There are three main elements to preventing contamination occurring in tubular heat exchangers: system design, production quality, and system maintenance.

 

System design

There are two main methods to prevent cross contamination between the product and the service medium (heating or cooling) due to leakage in tubular heat exchangers. The first is to maintain a positive pressure difference between the product and the service fluid, so that should a leak occur, the product will always flow into the service fluid rather than vice-versa.

The option is to introduce a physical separation between two different tube plates: one for the product and one for the service fluid. This means that in the event of a leak from either the service fluid or the product, the material flows into a safety container or other vessel and no mixing of the two materials is possible. Because this option relies on a physical barrier, no additional systems are required, making construction, operation and maintenance of the heat exchanger much simpler. For this reason, HRS Heat Exchangers use the double tube plate system in food production situations where contamination needs to be prevented, and double tube plates are included as standard with our S Series models of multitube heat exchangers (with different finishes for different purposes, including the SP Series specifically for pharmaceuticals and fine chemicals).

The gap between the two tube plates will depend on a number of factors, including the food products being processed and the space available for the installation, but can be effective even when the distance is just 3mm. Depending on the materials being used and the type of situation that the heat exchanger is used in, the gap between the two plates may be shrouded (with appropriate drain or inspection ports) or open.

 

Heat exchanger construction

Not only is the quality of materials important (such as the use of stainless steel), but so too is the quality of construction. Welding needs to be precise and joints (whether rolled or welded) need to be smooth to prevent product fouling or lodging of product, while also being strong enough to maintain integrity under pressure. Most manufacturers will be happy to arrange for you to see their production facilities and to provide information on their fabrication processes and standards if required.

 

The importance of cleanliness

It is obviously important to regularly clean, inspect and maintain heat exchange equipment in line with the manufacturer’s recommendations. Regular cleaning will ensure that drain holes etc. operate correctly in the event of a leak, while maintenance and cleaning will reduce the risk of leaks occurring and provide an opportunity for any repairs.

As well as being designed to prevent contamination via the double-tube plate, the HRS S Series also incorporate hygienic design and construction elements such as surface roughness, clean welding and the prevention of inaccessible areas or corners where dirt and/or cleaning chemicals may build up – meaning that CIP is as effective, timely and energy efficient as possible.