Questions about the pump

We have one pump in operation and two as backups, because the previous pumps tended to break down too often. A configuration of two in operation and one as backup is commonly used when expanding the capacity of a system: the original pump remains in use, another pump is added; one pump operates at low load levels, while two pumps operate at high load levels. There are also two pumps with the same medium and the same performance requirements, each serving a different process; they share one spare pump.

Determined based on flow rate and head; generally one in use and one as backup

The number of units required and those for backup is determined by the manufacturing process. If one pump is not sufficient to meet the required flow rate or pressure, it may be necessary to use two pumps simultaneously.

There is no fixed rule for this; it mainly depends on your design concept, as well as the approved annual operation and maintenance schedule. Traditionally, backup units are required for moving equipment. But now, with the improvement in manufacturing standards and techniques for analyzing mechanical equipment failures, many large-scale mechanical devices abroad either do not have spare units, or they do have spares but keep them in storage; when needed, the damaged unit is removed and the spare one is installed in its place. Interestingly, a design institute once proposed (perhaps at the request of foreign clients, though this is not in dispute) to equip two gas turbine generators with a rated capacity of 100+ MW each with a spare unit of the same capacity, resulting in a configuration of two in service and one as backup. GE and Siemens say that the online rate of our units (on a global scale) is over 98%, so there is no need for backups at all. And if you set up a backup unit, it will affect the overall online rate statistics for the aircraft fleet in our company.

The reason for installing backup equipment is mainly determined by the importance of the device and the requirements for continuous operation.

Usually, it is one in use and one as backup; sometimes two are in use and one as backup, but only in special cases is it possible to have two in use and two as backup

Of course, even for devices that aren’t important, there are ones without backup units

Requirements for the installation of pumps for transporting flammable and combustible liquids: 1) When transporting liquids with special requirements, dedicated pumps as well as backup pumps should be installed； 2) For pumps that convey the same liquid in a continuous manner, when no more than 3 pumps are in operation at the same time, it is advisable to have 1 spare pump ； When more than 3 pumps are in operation at the same time, the number of standby pumps should not exceed 2 ； 3) Pumps that are operated frequently but not on a continuous basis should not have a separate backup pump; they can use pumps that handle liquids with similar properties as backups, or share one backup pump ； 4) For pumps that are not operated frequently, it is not advisable to install a backup pump.

This is determined based on design parameters and process requirements

Generally, one unit is in operation while one is in standby; for those with significant variations in process parameters or process loads, two units are in operation while one is in standby. Additionally, in environments with complex processes and high equipment failure rates, two units are used with one in standby