January Newsletter
VOLUME 30, NO. 1
Aside from keeping a processing system clean and sanitary and having attractive well designed equipment, what steps should be taken to assure that an installed processing system has a pleasing appearance? One major factor is the design of support structure, operating platforms and catwalks. Good system design will assure accessibility for operating, maintenance and cleanup personnel, minimize the number of legs required and provide for structural integrity. The system designer has to know the operation well enough to be able to provide adequate accessibility for plant personnel. The need to minimize the number of legs cannot be overemphasized. Not only do legs cost money, they are an impediment to cleaning the floor. While structural integrity almost speaks for itself, the seismic zone needs to be taken into account. Support structure must be designed to meet the requirements for the seismic zone where it will be installed.
The best approach for designing catwalks, support structure and operating platforms is to start with good comprehensive layout and elevation drawings of the processing system. Catwalks and support structure should always be designed as an integrated structural system. Large operating platforms may be either designed as a stand alone structural system or be combined with the catwalks and support structure. Obviously the nature of the processing system will influence, if not dictate, basic structural design. A large french fry potato blancher is very capable of supporting the catwalks that normally are installed on each side of the blancher. Conversely, it is often most expedient to support small conveyors from the catwalks or from larger equipment. In any event the number of legs should be held to a minimum and structural members should be combined wherever practical. An example of this is to use one leg to support the ends of two connecting conveyors. Often in the design stage a smaller number of large structural members can be used instead of a large numbers of smaller members. A big rectangular tube is easier to clean than a truss.
Stainless steel is the material of choice for the majority of the catwalks and support structure being manufactured today. This has not always been the case. During the 1970’s, Gem Equipment manufactured a significant number of aluminum catwalks and support structures. This was triggered by regulations, proposed by USDA in the late 1960’s to minimize the opportunity for rust, paint chips and other foreign material to fall into and contaminate product. At that time stainless steel diamond plate was a very expensive specialty product and stainless steel square and rectangular tubing was practically unavailable. Aluminum diamond plate and small sizes of square tubing were readily available, and marine grades of aluminum functioned well for food processing plant catwalks and support structure. An additional advantage of aluminum was diamonds that were sharper and as a result was more slip resistant than either stainless or carbon steel diamond plate. Even though stainless steel components are readily available and aluminum prices have increased, reducing the use of aluminum in food processing plants, Gem still has a customer that purchases aluminum diamond plate catwalks.