What is the purpose of a sandwich diaphragm in a hydraulically activated diaphragm pump?

The purpose of a sandwich diaphragm in a hydraulically activated diaphragm pump is primarily to help prevent product escape with a rupture sensor. This design feature is critical because it enhances the safety and reliability of the pump system. When the diaphragm experiences a rupture, the sandwich construction allows for any potential leakage to be contained between the two plates, and the rupture sensor can immediately detect this issue. This effectively minimizes the risk of contaminants escaping into the environment, thus ensuring that the pump operates safely and effectively.

The other options do not align with the primary function of a sandwich diaphragm. High temperatures over 500 C, for example, may require different materials or designs, and while stopping leakage past the packing is a vital concern in many pumping systems, it is not directly related to the role of the sandwich diaphragm. Finally, allowing leakage between the two plates would be counterproductive to the design's intent, as preventing product escape is the primary goal of adding such a diaphragm in the first place.