We have an application for pumps handling hot oil at 700 deg F. What special care should we take in selecting and installing such pumps?
A. Pumps for handling oils within the range of 150 deg C to 450 deg C (300 deg F to 850 deg F) are commonly termed hot oil pumps. It is important that sufficient NPSH be available, as the liquid is almost always near the boiling point. Provision should be made to allow self-venting of vapors from the impeller eye by venting the suction eye of the first stage except where the suction nozzle is in a vertical upward position. The stuffing boxes and bearing housings should be provided with cooling jackets. The glands should be of the smothering type. If packing conditions require seal oil, lantern rings-together with the necessary pipe connections-should be provided. During operation, the seal oil pressure in the lantern ring should be held to a minimum of 175 kPa (25 psi) above stuffing-box pressure. Mechanical seals must be chosen specifically for the oil, temperature, pressure and speed. The materials used for the construction of hot oil pumps should have a uniform coefficient of expans
