Wellpoint dewatering pumps are used for groundwater extraction. The aim is to temporarily lower the groundwater table in order to work in dry conditions in underground construction and renovation projects.

BBA Pumps developed a piston pump in the 1990s specifically for wellpoint dewatering applications. Over the years, the concept of the piston pump has grown into the current PT wellpoint pump series. In addition, new innovations have ensured that we now pump groundwater very efficiently and in an environmentally friendly way. For example, with a wellpoint dewatering pump, we only move water where it is really necessary.

Piston pumps for dewatering

The design of the piston pump is based on the principle of positive displacement pumps. The extracted groundwater is displaced to the discharge point by the pump. A major advantage of piston pumps is that they can also handle a mixture of both air and water. When wellpointing, you often see that as the groundwater level drops, a lot of air comes with it. For this reason, piston pumps are well suited for wellpointing due to their ability to run dry indefinitely and pump both water and air mixtures.

The vacuum performance of piston pumps is unique. When lowering the groundwater table in deep construction pits, the vacuum can become high. Under such operating conditions centrifugal pumps can become exposed to cavitation or, due to their NPSHr characteristics, simply not useable for the job. Piston pumps, on the other hand, can draw up to almost full vacuum from a wellpoint system. Perhaps nice to know: when we test a PT pump, the suction connection is completely closed with a blind cap. We are only satisfied when the pointer of the vacuum meter comes close to -1 bar (-30 inHg).

And then the lifespan of a piston pump for wellpointing! The first PT pump was produced in 1989 and by now thousands are pumping groundwater all around the world. Wellpoint dewatering pumps only run at an average of sixty strokes per minute. Built with extreme robustness, they are equipped with top quality bearings and other high performance rotating parts. An average piston pump runs 24/7 for decades from one wellpoint systems to the other.

How a wellpoint pump works

The piston inside the pump moves up and down inside a cylinder. This causes the space in front of and behind the piston to alternately become larger and smaller. A valve system takes care of the rest. During the extraction of groundwater, the pressure valves close and the suction valves open automatically. A vacuum is created on the suction side and the groundwater flows into the pump housing. When the piston moves in the opposite direction, the suction valves close, the discharge valves open and the groundwater is pumped out.

BBA Pumps PT piston pumps have two pistons and cylinders as standard. This reduces the pulsating effect during wellpoint dewatering and doubles the pump capacity. Leather cups are used for the seal between the pistons and the cylinder walls. This ensures that PT wellpoint dewatering pumps can run dry without problems. If groundwater is not pumped the leather cups become dry and reduce in size. This decreases any internal friction and the risk of wearing, and as soon as the leather becomes wet again, the cups automatically return to their original shape.

Lowest cost of ownership with PT piston pumps

Wellpoint dewatering companies typically have dozens or even hundreds of piston pumps in their fleet. This means that they can only afford to operate pumps with the lowest cost of ownership. When BBA Pumps develops a new wellpoint pump model, attention to maintenance is given a high priority. The new pump must be very simple to operate and effortless for maintenance engineers to work with. Further, maintenance costs must be as low as possible for the owners of dewatering companies.

As wellpoint dewatering is a 24/7 process, piston pumps must run for many operating hours. High pump efficiency is the key to keeping energy costs low. It does not matter whether the pump is driven by a combustion engine or an electric motor. With our PT piston pumps the energy consumption is extremely low, which is an another important reason why dewatering companies only use piston pumps to lower the groundwater table.

Key features of BBA Pumps wellpoint pumps

BBA Pumps is committed to building the world's best portable pumping solutions. Our superior performance is often the result of smart technical features that deliver huge advantages for wellpoint dewatering companies. We would like to give a few examples:

• Each PT piston pump is equipped with a large number of aluminium access covers with a handle as standard. This makes it easy to access the pump for internal cleaning, quick inspections or maintenance work. This saves valuable time for pump technicians.
  
  
• A stone catcher is located on the suction side of the PT piston pump to prevent suspended solids from entering the pump housing. This contains a mesh which can be easily accessed for cleaning via the cleaning covers.
  
  
• The stone catcher is fitted with a module with two vacuum gauges and a regulator valve. One gauge displays the vacuum on the wellpoint system. The second gauge shows the vacuum in the piston pump. The regulator valve is used when the vacuum on the wellpoint system becomes unnecessarily high. Adding more air makes the piston pump run with reduced noise and improved efficiency. Pump professionals greatly appreciate these types of technical features!
  
  
• The drive section of the piston pump has received a lot of attention. Special lubrication channels and perfectly finished gears ensure that dewatering companies can use the pumps for groundwater extraction for decades to come.
  
  
• BBA Pumps develops its own concepts for the drive of its wellpoint dewatering pumps. A good example is the DriveOn^® innovation, where the service interval of the diesel engine has been extended to 1500 operating hours. The super quiet sound-attenuated canopies are also important for groundwater extraction. Even when the groundwater table is lowered in repair projects at local sewage works, the super quiet functionality makes it possible for nearby residents to remain undisturbed and get a good night’s sleep.  

Wellpoint systems

In addition to piston pumps for groundwater extraction, we produce all the additional items needed to complete wellpoint dewatering installations. Visit our wellpoint systems pages. Here you will find everything about HDPE header pipes, wellpoint filters, wellpoint hoses, quick couplings, water flow meters and settlement tanks.