Drainage pumps for water: types, device, operation features

Nikolay Fedorenko
Checked by a specialist: Nikolay Fedorenko
Author: Elena Nikolaeva
Last update: March 2019

Drainage pumps are indispensable assistants in solving many problems associated with the transportation of water. Due to their compact dimensions and ease of installation, these “universal soldiers" will help to cope with any problem in a short time - from pumping unclean water from a well to draining a site.

In order for the unit to cope with the tasks assigned to it, and the purchase paid off for uninterrupted operation, it is necessary to carefully approach the issue of choosing a device.

We will tell you how drainage pumps for water work, which models are appropriate to use in a particular situation. In addition, we denote reliable manufacturers of equipment and list the main selection criteria for drainage pumps.

Drainage pump design

The design of any drainage pump, whether domestic or foreign, has a similar configuration and general principle of operation. An electric motor with a pump assembly is placed in the housing of the unit.

The working elements of the electric motor are the stator, rotor and bearing shields. A leading working “organ” is planted on the rotor shaft - a centrifugal impeller, referred to as the impeller.

Suction openings are provided in the pump assembly. The diameter of these inlets determines the maximum amount of solid particles that the device can pass through itself.

The main elements of the unit
The unit is usually equipped with universal adapters suitable for connecting both flexible hoses and rigid pipes Ø 1ʺ and 1 1 / 4ʺ (+)

For safe operation of movable mechanisms, the pump unit of the unit is equipped with:

  • thermostat - turns off the device when the engine warms up to a critical temperature;
  • float switch - reacts when the level of the processed liquid decreases to a critical value.

A float switch is a set of sensors enclosed in a sealed polymer box.Thanks to the air inside the box, it, like a float, is always on the surface of the water and moves after its level.

Float mechanism
The float mechanism is equipped with an electric switch and a steel ball, which opens and closes the contacts of the circuit at the slightest change in the position of the float

Today, more and more often you can find devices equipped with the new aquasensor technology. They are effective when it is necessary to equip narrow tanks, in the cavity of which the placement float switch does not seem possible.

Using this built-in regulator, it is convenient to set the desired water level for automatically turning the device on and off. The minimum level can reach a retraction of only 5 mm.

If the drainage unit is used regularly, rigid pipes are brought to it. In case of periodic use of the pump for connecting sufficiently flexible hoses.

The principle of operation of the unit

Pumping water, a drainage pump diverts it from a filled tank or flooded room to a nearby facility. In this case, the processed liquid first enters the working chamber, and then, thanks to the created pressure, it moves towards the outlet pipe under the action of the pump wheel.

Thanks to the arrangement of most drainage pumps, in which the impeller is half open, the units are capable of pumping large portions of liquid as soon as possible.

Empty the barrel with a pump
Due to the fact that devices of this type are not able to create large pressure, they cannot lift and pump water over long distances.

The pumped liquid simultaneously performs the function of cooling the engine. Due to this, the probability of overheating of the pump during prolonged operation is reduced to zero. But for the same reason, manufacturers of drainage pumps impose a limitation on the maximum temperature of the pumped water. For most models, it should not exceed 50 ° C.

On sale there is also equipment that is able to work in unusual conditions and hot environments. But such equipment costs an order of magnitude more expensive.

Drainage pumps are able to work effectively in environments with varying degrees of contamination.

Units on sale are divided into three categories:

  1. For clean and slightly contaminated water. Pump water with the inclusion of particles with a maximum size of 5 mm. They are used for water intake from water-reducing wells, emptying pools and pumping water from rain tanks.
  2. For medium polluted waters. The size of solid particles transported with water does not exceed 25 mm.They are used to empty storm drains, drainage wells.
  3. For dirty liquids with inclusions of 38 mm. They are floated to empty the storage tanks pumping dirty water with flooding.

The performance of devices designed for clean and slightly contaminated water ranges from 83 to 230 l / min. And the supply of pumped liquid can reach from 5 to 12 m.

Providing a drainage system
These parameters are quite enough to ensure the operation of fountains, water supply systems, water disposal, as well as the operation of irrigation systems

For pumping dirty water, including gravel and similar particles with a diameter of 10 to 15 mm, units with a capacity of 37 to 450 l / min are used. They are able to provide water supply to a height of 5 to 22 meters.

Industrial drainage models created for work with sewer systems, can "digest" particles up to 120 mm in size.

Lower surface water
The main difference between drainage systems and borehole pumps is the ability to pump out water, which contains various kinds of impurities

Drainage plants are able to work as efficiently as possible only with liquid, in which the minimum content of solid elements.

Contaminated water saturated with solid waste can be dealt with. fecal pumps with a grinder.

Type classification of pumps

The variety of pumping equipment is divided into two categories: surface and submersible units.

Surface Models

Surface units are designed to be installed above the tank. A device case of this type is placed on a flat surface in a dry place. Water is pumped out through a sleeve lowered into the tank: a PVC pipe or a rubber hose.

Outdoor unit
Surface pumps are mobile and easy to operate: they are convenient to carry around the site, installing in the right place temporarily or permanently

Any model of surface execution has two pipes:

  • input - provides the flow of wastewater from a filled tank;
  • day off - diverts effluents beyond the limits of the devastated structure.

Such devices can operate in automatic mode. To implement automatic operation, a float mechanism that responds to the liquid level in the tank is connected to the toggle switch.

It is immersed in the pumped liquid along with the hose. When water rises above a certain mark, the sensors of the float that control the start of the pump are activated.

The main advantages of submersible units are:

  • simplicity of installation and dismantle;
  • Maintenance of the device is limited to timely cleaning and lubrication of parts.

But such aggregates are not suitable for deep sources. They are designed to work with a suction height in the range of 8-12 m.

It should also be borne in mind that when connecting such a pump to the sewer system, you need to know exactly the cross-section of the pipeline, since the unit is connected to it using pipes.

Submersible Drainage Devices

Submersible instruments operate in much the same way as surface drainage pumps. But they are more designed to pump water from deep trenches or well cleaning.

Pumping of wastewater is carried out by the pump itself without involving hoses and pipes. A strainer located at the bottom of the pump protects the unit from solid soil, sand and insoluble particles.

The maximum immersion depth of the pumps for different models usually does not exceed 50 m. But they cannot be used when emptying shallow reservoirs and ponds, the depth of which does not reach 20 m. For the possibility of the operation of submersible devices in shallow trenches, it is necessary to use additional engine cooling with water.

Submersible Pump Installation
Submersible units are installed at the bottom of the tank, and water is sucked in directly through the grill located in the lower part of the housing

The installation depth of the unit depends on the type of tank. But there is a simple pattern: the lower the submersible pump is, the easier it will work.

Among the main advantages of submersible devices it is worth highlighting:

  • high power and performance compared to surface units;
  • the possibility of draining deep reservoirs a few tens of meters;
  • quiet running - units immersed in the tank practically do not produce noise during operation.

A feature of installations of this type is that they work automatically. Equipping the device with a float mechanism or a plastic bubble ensures uninterrupted operation of the pump in automatic mode. It turns off the pump motor when the set water level is reached.

The device with a float mechanism
The presence of a float switch is especially relevant when it is necessary to pump liquid from slowly filling tanks

The constant operation of the device under water requires reliable isolation of automation and sealing of the device’s electric motors. Therefore, in the manufacture of submersible units, only corrosion-resistant materials that can withstand mechanical damage are used.

The manufacturing material for nodal parts, depending on the purpose and perceived loads, may be:

  • polymers and engineering plastics;
  • electrical, alloy and carbon alloys and steels.

In expensive models, gaskets made of ceramic cuffs or with an oil lock are used to seal the electric motor of the device.

The only drawback of immersion devices is that for maintenance and drain pump repair, it has to be removed from the tank to the surface. And due to the tightness of the housing, it is quite problematic to maintain and repair them.

Types of pumps for the intended purpose

Depending on the capacity of the devices and the field of their application, drainage pumps are conventionally divided into two types: domestic and industrial.

Units of household use

Drainage pumps designed for domestic use have a wide range of applications.

They are used:

Single-phase low-power pumps have an average capacity of 800 l / min and are capable of moving water extracted from a tank, pond, well to a height of up to 25 m.

Establishment of an irrigation system
Drainage installations are often used in irrigation and irrigation systems, as well as in ensuring fast water supply for the functioning of the fountain

For household needs, drainers are most often purchased, the case of which is made of stainless steel or reinforced polymer. They are able to pump water with the inclusion of solid impurities up to 10 mm in size, the ratio of which is 10% of the total volume.

Industrial pumps

Industrial drainage pumps have higher power and performance. Motor-pump and diesel-pump units are widely used by utilities, construction companies and the Ministry of Emergencies.

With their help produce:

  • pumping of sewer tanks and clogged pipelines;
  • elimination of emergency flooding;
  • removal of industrial drains;
  • drainage of collector pits and other objects.

On an industrial scale, drainage pumps are most often used with electric motors placed in cast-iron housings. A powerful radiator of such devices provides effective heat dissipation, and a cast-iron case protects against deformation with significant heat generation.

Industrial unit
They are able to pump waste water and dirty water, including particles up to 20 mm in size, the ratio of which is 25% of the total

Industrial three-phase pumps are characterized by a suction rate of up to 1,500 l / min. They are able to raise the recyclable water to a height of about 150 m.

Such models have a more complicated design. For maintenance, they require a specialist.

Leading manufacturers of drainage pumps

The pumping equipment market today offers a wide selection of drainage units from various manufacturers, both domestic and foreign.

Among buyers, the most popular models are those produced under such trademarks:

  • Grundfos - The Danish company specializes in the production of pumping equipment, including electric motors and components for them. A wide range of products includes both external and immersion devices designed for pumping clean and dirty water of various temperatures. Units manufactured under this brand belong to the high-price segment, since the prices for models are one and a half times higher than the average mark.
  • Perdollo - The Italian company, guided by the principle of helping humanity in solving problems of providing water, produces new generation pumps. The manufacturer’s catalog contains hundreds of models that differ in purpose, design and performance. Wear-resistant and reliable devices manufactured by them, despite their rather high cost, have a sea of ​​positive feedback from customers from all over the world.
  • Wilo - The German brand, which appeared on the domestic market more than two decades ago, is famous for introducing the latest technologies and modern design. The company produces high-quality equipment for water supply and sanitation, as well as ventilation and air conditioning.

At the enterprises of each of the listed companies there is a multi-stage quality control. Their products comply with international quality and safety standards.

Recommendations for choosing equipment

The first thing you should aim at when choosing a unit is the conditions for its use and the degree of water pollution.

Pump strainer
The diameter of the nominal bore of the pump will correspond to the maximum size of solid inclusions that it is able to pump

When choosing drainage equipment for water, you should focus on the technical characteristics of the product:

  1. Performance. It is determined from the calculation of the amount of work that the unit must perform.That is, how much fluid he must pump out over the specified time period. The emphasis should be on the most complex process.
  2. The pressure. To determine this parameter, you should know the approximate height and distance over which it is planned to transport water. This indicator is calculated as the difference between the water outlet mark from the nozzle and the immersion depth of the unit.
  3. The pumped-out environment. The maximum permissible size of solids to be pumped with water is specified in the instrument specification. In models designed to work with contaminated water, the dimensions of the working chamber must be such as to ensure unhindered passage of fractions.
  4. The maximum temperature threshold. When choosing a submersible model, be guided by the maximum temperature threshold of the pumped liquid, since the engine of such an aggregate is cooled by the transfer of thermal energy to the transported liquid. In most cases, the maximum water temperature threshold is 50 ° C.

The maximum productivity of household units is 180 l / min. This is enough to drain the tank or remove water from the cellar. In order to be able to pump water from the bottom of the tank or well in optimal mode, choose models whose suction openings are located below.

When calculating the required power, one should take as a basis the parameter that one meter of vertical water intake will correspond to ten meters horizontally.

Dependence of productivity on lifting height
The pressure and performance of the drainage pump are interconnected: the greater the immersion depth of the device, the less the created pressure (+)

When choosing a model, also take into account the condition of the surface where the equipment will be placed. It is better to place the surface drainage pump in a pit 40x60 cm in size. This will prevent water from spreading on a flat surface.

If you use automation, involving the vertical location of the float, the surface will remain completely dry. Indeed, when properly configured, the float mechanisms work properly and reliably.

Regardless of the type of model designed for pumping clean liquid, it should be borne in mind that it should not be operated near a silty or sandy bottom of a reservoir. Particles entering the device will clog it, which can adversely affect the life of the unit.

For more information on the design features of drainage pumps and tips for choosing equipment, see this article.

Conclusions and useful video on the topic

The principle of operation of the drainage equipment:

Rules for the proper choice of a drainage pump:

Classification of drainage pumping equipment:

The drain pump is a versatile technique that can perform several tasks. Having come to the right choice of model, you can use one pump in several processes, so you get a great opportunity to use the unit for a long time and fruitfully.

Looking for an efficient and reliable drainage pump for water? Or have experience using such installations? Please leave comments on the article and share your impressions about the use of drainage pumps.

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Visitors Comments
  1. I can say about Grundfos brand pumps, as I had experience using them with the Unilift KP 150-A1 model. The pump is not cheap, but it is very reliable and durable, which is facilitated by the presence of a metal casing. It’s also very productive. At the same time, it is also quite economical in energy consumption, among its class one of the best. True, he also has a minus - you must separately buy a non-return valve.

  2. Victor, Samara

    I’m without a drainer, like without hands, because every year I drown the basement twice a season, and there are shelves with all kinds of things, blanks for the winter, etc. Only the pump and save myself. The only thing depressing is the low quality of the filters. I have a budget model and, apparently, only budget models are also produced for it. Large fractions deform them, change them once a season. I recommend everyone who has the same problem with basements to think about purchasing a drainage device - it really helps.

  3. Capil

    Tell me a normal drainage pump for pumping dirty meltwater from the basement. Preferably inexpensive.