Custom Challenge  - Volume 1-   by Barney Sievers

    This oven was based on our standard Model ST and is in reality two separate ovens, one atop the other, but on the same support frame. It is a Class 1, Div 1 explosion-proof design. The entire project consists of 3 main components, the 2 ovens on a single support frame, a separate vacuum pump and collection tank skid, and the electrical enclosure. Once again it features backup programming capability allowing either one of two pumps to be designated as the primary pump for either or both ovens, or both pumps can be run simultaneously to only one oven.

    Each oven features an optional four-inch viewing port, proximity sensors for the custom made material handling racks and product pans/shelves that are transported on a custom stainless-steel cart. Integrated into the design are six dispensing tubes, one for each product pan/shelf that allowed for remote filling of volatile hydrocarbons. These ovens both feature a modest vacuum requirement of only 42 Torr, electric heating to 75°C, air or nitrogen backfill capability, and water-cooling capability accompanied by an air purge circuit to flush all water out of the cooling system while under thermal processing.

    Since one of the primary design specifications was to capture volatile hydrocarbons during the vacuum cycle, a separate heat exchanger/condensation system has been integrated that condenses the hydrocarbons and routes them to a stainless-steel holding tank for removal via either a manually operated or pneumatically purged to the customers waste tank system. Since the holding tank has level sensing switches, the pneumatic circuit was programmed to occur automatically as specified during the process profile.

    This oven was one of the more challenging to manufacture due primarily to the complex valve logic that was required to control the twenty something valves. Even so, the customer was ecstatic with the results that far exceeded their expectations for product manufacturing and OSHA compliance.