What are InLine Vertical Pumps?

An In-line Vertical Pump is a type of centrifugal pump that has a vertically oriented shaft, with the suction and discharge connections in the casing in line with each other, rather than requiring a change of direction like end suction pumps. They are commonly used as circulator pumps in situations where water flowing through a piping system needs to be pressurized. Some are designed to be easy to fit into a residential or commercial piping system, and they are commonly used for chilled water and hot water circulation in commercial buildings.

The main advantage of this pump configuration is the floor space savings that this creates, as compared to a horizontal end suction pump. A secondary advantage is that the piping is simplified, since the piping does not have to change direction as it does with an end suction pump. In many commercial building applications, in-line circulators are simply suspended in the piping, just like a valve.

Uses of vertical inline pumps

An inline pump can serve all kinds of uses, they may be used as irrigation pumps to help boost water from the well pump or water source to the crops, additionally they can also be used as booster pumps in municipal water supply systems, where they are used to boost the pressure of water from the treatment plant to homes located far from the municipal water supply.

Advantages of vertical design:

  • It requires a smaller footprint and is suitable for installation where the ground surface area is limited, or is at a premium.
  • With a vertical shaft pump the impeller sitting below the ground can be lowered to increase the site NPSHA.
  • It is suitable for higher temperature service. Because of its radial-split case design it can be centreline mounted for even thermal expansion.
  • It is suitable for higher pressure service because of its simplified bolting and confined-gasket design.

Disadvantages of vertical design:

  • Most vertical design, particularly the multistage units, or the so called “vertical shaft turbine pumps”, require large headroom for installation, servicing, and maintenance.
  • It is usually suitable for direct coupling to electric motor. Using other type of  driver, such as engine or turbine, will require a right angle gear drive and, possibly, a universal shaft joint and a clutch.
  • Being of an overhang design, its hydraulic axial thrust is difficult to balance in high suction pressure service.
  • A multistage pump usually requires expensive sump pit and barrel.
  • It is prone to mechanical seal problems when pumping liquids with high dissolved or entrained gas which accumulates at the top of the stuffing box or seal chamber where venting can be difficult or less effective.