Injector Pumps

What is an injector pump?

Injector pumps are a special type of deep-suction jet pump. While the pump remains at the surface, the part called the injector (ejector) is lowered into the well, below the water level. The pump sends a portion of the water it discharges back down through one pipe to the injector; the vacuum created at the injector draws water from the well up to the pump through a second pipe. This method makes it possible to draw water from depths that surface pumps cannot normally reach.

When is it the preferred choice?

• When the pump is to be installed at the surface rather than inside the well
• When running an electrical cable into the well is undesirable
• When the wellhead is easily accessible and maintenance is to be carried out at the surface
• When the water level is below the suction limit of standard jet pumps

The suction depth stated in the product name indicates the approximate depth reachable based on the level at which the injector will be positioned.

Advantages and limitations

The greatest advantage of injector pumps is that the mechanical and electrical components remain at the surface, making the pump easily accessible in the event of a fault. However, because a portion of the water circulates continuously, their efficiency is lower than that of submersible pumps and they consume more energy for the same flow rate. For very deep wells and high flow rate requirements, borehole submersible pumps are a more economical option.

Installation notes

The injector should be positioned below the water level but sufficiently above the bottom of the well. Both pipe lines must be completely leak-free, and a check valve or foot valve must be installed on the suction line. On first start-up, the pump and pipes must be primed with water.

Frequently asked questions

How many meters deep can an injector pump draw water from?

The reachable depth varies by model and injector type; use the suction depth value in the product description as your reference.

What is the difference from a standard jet pump?

In standard jet pumps the ejector is in the pump body and suction depth is limited; in an injector model the ejector is lowered into the well, allowing water to be drawn from much greater depths.

Can it be used in a sandy well?

Sand can wear and clog the injector; position the injector well above the bottom and use a strainer.

Can it be used as a booster pump?

A booster pump system fed from the well can be set up by adding a pressure switch and tank.

How much electricity does an injector pump consume?

Because a portion of the water circulates continuously, it consumes more energy than a submersible pump delivering the same flow rate. For long-term and high flow rate use, operating costs should be evaluated from this perspective.