Abstract: This invention relates to a deep fat fryer of the external heat exchanger, pumped-recirculation type, and more specifically, discloses a control system for automatically heating and recirculating the fat either continuously or intermittently as needed to accommodate one or both of two conditions existing in such a fryer. First, during continuous circulation and frying vapor lock may occur at the pump impeller, inhibiting recirculation. Automatic shifting to intermittent operation is made to occur until the vapor "burps" itself from the pump. Additionally, when starting a fryer and using solid shortening, the pump and burner are operated intermittently until such time as the pump and heat exchanger are sufficiently full of melted shortening to permit continuous circulation. Upon sensing that full condition and our associated pressure, the system shifts automatically to continuous recirculation.

Abstract: A pressure cooker canning unit for batch canning, the canning unit including a pressurizable retort having a highly accurate control and monitoring system for temperature regulation and recordation, the retort having a pressure gauge and a thermometer tree for visual monitoring of the pressure and temperature in the retort, a temperature probe and connected temperature recording device for continuous recording of the temperature within the retort and a pressure relief valve for safely releasing excess pressure in the retort, the retort being heated by a gas burner with a gas flow regulated by a unique flow control valve modulated by the pressure within the retort for maintaining a constant temperature within the retort.

Abstract: Time controlled switching apparatus is connected in series circuit with a steam pressure sensor and a line starter associated with a boiler firing system. The switching apparatus is rendered electrically conductive during spaced time intervals of successive hours whereby boiler firing occurs during preselected time periods and then only where generated steam is at preselected pressure level.