Profile: A P Sales & Services offers a comprehensive range of products such as pig tron, welding electrodes, centrifugal pump mechanical seals, steel bends and industrial valves. Our centrifugal pump mechanical seal acts as a check valve and a slider bearing. The obvious function of our centrifugal pump mechanical seal is that of a check valve to prevent liquid under pressure from leaking out of the pump, or from drawing air into the pump under vacuum conditions. The O-ring, or cup, and flexible diaphragm of the seal are made of rubber-like substance called an elastomer. The type of elastomertic material is selected to match the temperature limit and types of material being pumped. The seal of a centrifugal pump is usually replaced many times during the life of a pump. All bearing need lubricant and the seal lubricant is the liquid being pumped. Liquid infiltrates between the contact faces of the primary and mating rings. The condition of the pumped liquid will greatly affect seal life. Our welding electrodes are used in the shielded metal arc welding (SMAW) process.