• • • ENCLOSURES • • •


What do you need from the enclosure for installation in food processing or pharmaceutical manufacturing environments?


Russell Irvine, sales manager, Europe, at Hammond Electronics highlights the prime function of enclosures in food processing or pharmaceutical manufacturing environments is to protect the housed electronic or electrical system from contamination


I


f your equipment is going to be installed in a manufacturing area where maintaining hygiene standards and avoiding contamination are


arguably the two most critical requirements – food processing and pharmaceutical manufacturing are two obvious examples – the enclosure will play a key part in enabling the installed equipment to be cleaned to the requisite standards by being hosed down with high pressure, high temperature water jets.


Enclosure requirements


Material Stainless steel is the default material for use in environments where corrosion resistance is a pre-requisite requirement. For internal use, 304 grade material is more than adequate. The widely available higher grade 316 and 316L stainless materials do provide greater corrosion resistance than 304, but the additional cost is unlikely to be justified unless repeated exposure to chlorinated solutions and chlorides, such as seawater, is expected.


Design criteria The washdown requirements for equipment installed in areas where hygiene is a key driver place specific criteria on the design of the enclosure. Hammond’s latest IP69/IP69K rated enclosure is the HYJ Series, manufactured from 304 grade stainless steel. Initially available in five sizes from 202 x 124 x 102 to 416 x 338 x 203mm, the family’s design ensures that there are no areas where contaminants can gather. The symmetric rectangular design means that


the units can be surface mounted either vertically or horizontally to suit the application. All sides are sloped to ensure that water quickly drains off after spray cleaning and a super-smooth finish to all surfaces also aids water drain. Some designs of stainless-steel enclosures


feature full length piano hinges that secure the door to the base, an obvious trap for dirt and dust. The HYJ cover is secured to the body with six crevice-free hex head bolts fitted with a silicone washer. The sealing is achieved by a distinctive blue


“hygiene” coloured silicone gasket, which is more resistant to the high pressure, high temperature


18 ELECTRICAL ENGINEERING • MARCH 2022


IP69/IP69K wash than other materials and is fitted beyond the door edges, so that there are no crevices in which dirt can collect. The blue gasket, which makes the majority of food contaminants more visible – we don’t eat many blue foods – can be easily removed for cleaning or replacement. Similarly, to reduce crevices and unnecessary


surfaces to eliminate spaces for bacterial growth, there are no slotted screw heads, quarter turn latches or welded mounting brackets. To eliminate difficult to clean areas behind the enclosure, pre-drilled mounting holes are not provided. It can be mounted with stand-offs, available in four different lengths, that ensure that the HYJ is fixed well proud of the wall to facilitate wash down of all faces. Complementing the HYJ family is the HYPB


range of push-button enclosures. Offered with both 22.5 and 30.5mm holes, the HYPB is available with a single row of 1, 2, 3 or 4 mounting holes; with four holes arranged in two rows of two or with six holes in a three-by-three configuration. Obviously,


the type of pushbutton should be selected with the hygiene requirements in mind.


IP69 and/or IP69K sealing The familiar, well-understood IP ratings against


the ingress of solid objects and water is specified in IEC 60529 – Degrees of protection provided by enclosures. Enclosure manufacturers offer many different styles in various materials meeting IP65, IP66, IP67 and IP68 requirements. However, when moving to IP69, the highest level specified in IEC 60529, a degree of confusion can creep in because of the widespread practice of referring to IP69 and IP69K as if they are one and the same. In fact, IP69K is actually defined in ISO 20653 – Road vehicles – Degrees of protection (IP code) – Protection of electrical equipment against foreign objects, water and access. The main difference between the two is in the test methodologies. Both specify that the enclosure is sprayed with


jets of water at 80°C from specified angles and distances. IP69 testing requires the force of a water jet to be defined; IP69K testing requires that the pressure of the water jet is measured. The maximum distance of the water jet nozzle can be up to 200mm in the IP69 test as compared to 150mm in the IP69K test, but other than that, the test requirements are very similar.


Conclusions Manufacturers of equipment and systems that have universal applications across a range of industries need to be aware of the additional requirements placed upon them when their products will be used in areas subjected to high temperature, high pressure washdowns. The enclosure manufacturer can help with selecting the best design for such applications.


Flow Spray Rotation Duration Distance Temperature Water pressure rate


positions speed


IPx9 15 l/m 0°, 30°, 60°, 90° 5 rpm 30s/ position 150 – 200mm 80°C minimum


or force 0.9 – 1.2 N IPx9k 15 l/m 0°, 30°, 60°, 90° 5 rpm 30s/position 100 – 150mm 80°C 8000 – 10000 kPa


From the enclosure manufacturer’s point of view, it makes good sense to have the product tested to both IP69 and IP69K.


electricalengineeringmagazine.co.uk


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