Fecal pumps for sewage (sewage fecal pump)

Fecal pump (sewer) is a system that pumps out and pumps from one place to another dense and viscous liquids, wastewater, fecal masses, sewage (including those with foreign solid particles of different fractions). For pumping liquids with solid inclusions, fecal pumps with a shredder are designed.

Fecal pumps are centrifugal pumps with a special design that ensures the passage of solid particles without clogging the pump.

A fecal pump is a device designed to pump domestic, municipal or industrial wastewater with pollutants, materials and even objects that may be present in them.

Pumps for fecal and other waters pump out liquid from various bodies of water, including outdoor pools. Water from such sources is used for watering the garden. Mud and organic particles are excellent fertilizers.

Fecal pumps pump wastewater from facilities without access to the central sewer. These are country houses, cottages, dachas, as well as individual buildings and structures.

Use of fecal grinding pump:

1. In homes with a significant number of sewer users, where it is not possible to control the quality of the waste being dumped.

2. Household fecal pumps are often placed in the kitchen, where food residues can get into the drain during dishwashing.

Fecal pumps are required for sewerage, if the system has pipes with a small cross-section – up to 5 cm. Although this is a violation of sewer installation standards, the network can be saved, but only when using a sewer pump.

The name of these devices contributed to the strengthening of the idea that they are used exclusively in sewage systems. But this is far from the case. The use of fecal pumps is also relevant, for example, in production and in agriculture to pump waste, wastewater and technical water or other liquids from drainage systems.

This equipment is also used to connect temporary sewerage or to dissempers in previously uninved premises.

During various types of repair work, modern fecal pumps perfectly replace sewerage. The device is convenient because when it is used, the pipeline is not clogged due to the high pressure during pumping.

Fecal pump design

It may be different, but in any case it is compact. The main components of the fecal pump:

• basis;

• body;

• control panel;

• power cable;

• engine (electric, gasoline);

• pump unit.

Suction holes are located at the bottom of the pump.

Types and features of fecal pump impellers

Let's start with the impeller, one of the most important components of hydraulics. It directly affects all the main characteristics of the fecal pump. The impeller rotates in the flow of liquid, transferring energy from the engine to it. Simply put, the impeller disperses the liquid. The most commonly used types of work wheels:

• channel (closed) – single-channel, multi-channel;

• vortex (open);

• semi-open;

• screw.

The best "non-hammering" and at the same time "gluttonous" in terms of energy consumption are fecal pumps with a vortex impeller. The most energy-efficient on clean water and at the same time the most "easily clogged" on wastewater are fecal pumps with a multi-channel impeller. The rest are somewhere in between, balancing between efficiency and resistance to clogging. Why is that?  

The channel impeller is in closest contact with the fluid — the entire flow passes through it, through the channel(s) inside the rotating impeller. Hence its names - canal or closed. And the main disadvantage is that if something large enough comes with the flow of liquid and gets stuck inside the impeller, it will sit off the flow and can rotate together with the impeller forever.

The multi-channel imper is also bad because the input flow is divided inside into several smaller (in terms of the number of channels) blade partitions. Each of which can and will be cling to rags, threads, ropes, feminine hygiene accessories... In addition, the presence of blades-partitions reduces the free passage, that is, the maximum size of the object that can pass through the pump.

The single-channel impeller, especially its modern versions, is quite good, well balanced mechanically. Provides quiet operation of the pump and is able to cope with many types of garbage. In a well-designed single-channel impeller, the channel has no narrowing, in section it looks like a curved pipe of constant (expandable) cross-section with smooth walls. The chances of getting hooked on the road for something in the garbage are extremely small. Everything seems to be perfect. 

А the channel is bent! Imagine that a plastic bottle from drinks, or with a drink, something else - screwed and quite hard and elastic – got into the sewer. Or a can of beer, or with beer. The perfect plug for the duct impeller! Almost a guaranteed problem.

In a simpler case, it can be a bone thrown from the plate. It will not cover the entire flow, but after it gets stuck, it will begin to cling to it and wind up more garbage, gradually reducing the passage. In agriculture, manure mixed with animal litter and cod in wastewater can be such a difficult for a channel impeller; in the processing industry, meat production waste, and so on. 

A good semi-open impeller will cope with such a problem once or twice. The tin, plastic bottle will be torn into pieces and thrown away with the liquid. And, characteristically, the amount of free passage in this device with a semi-open impeller can be two to three times less than in a channel in which the same bottle or wool is stuck.

That is why the amount of free passage cannot be an unambiguous indicator of the "non-killing" of the fecal pump. It is worth noting that the hydraulic efficiency of the best samples of fecal pumps with a semi-open impeller is comparable to the hydraulic efficiency of pumps with a channel impeller. And in some cases, it is not at all inferior to him.

The vortex impeller interacts with the fluid flow more weakly than the others. Unlike the semi-open one, where most of the flow passes between the blades, it is pushed as deep as possible so as not to block the path of the liquid from the inlet pipe to the outlet.

In english-language literature, along with the term "vortex impeller" (vortex impeller) is also used "recessed impeller" (recessed or recessed impeller). This feature explains both the low hydraulic efficiency of such devices and the low value of the maximum pressure. And thanks to it, maximum "non-beatability" is achieved - there are no obstacles to the path of the liquid inside the pump.

The helical impeller is close to the single-channel one in terms of "non-beatability" and efficiency. At the same time, it has a better parameter NPSH (pure hydraulic pressure), which can be very important under certain conditions.

The principle of operation of the fecal pump

It works as follows. When the electric motor is started, the drive shaft begins to rotate. It rotates the impeller, creating a centrifugal property inside the vorge injection chamber. This stimulates the suction of the liquid inside, where it is cleaned, filtered and transported to a given place of drain.

Water (pumped out or pumped) enters a special container under a certain pressure. With the help of the pumping unit, it enters the suction nozzle, and from the pumping nozzle, it is disposed of into the sewer or other place.

Fecal pumps can be: automatic, manual or double-hand. The dual-mode has a fork that allows you to use it:

• in manual mode, when the switch is bypassed and connected directly to the outlet;

• automatic, while the fecal pump is connected via a floating switch and works only when it is switched on.

• the presence of foreign objects and materials in wastewater complicates the operation of the fecal pump and imposes special requirements on its design.

Features of the design of sewer pumps

The material for the manufacture of fecal pumps can be stainless steel, cast iron and plastic. Steel products have a high price, but they are durable and have a long operational resource.

Cast iron models with a significant weight, which affects the installation of the fecal pump and maintenance. In terms of cost, they have an intermediate space between steel and plastic copies. Plastic fecal pumps are the cheapest and are made from different types of plastics.

Surface sewer pumps are installed outside the capacity near the pumping site. They have low throughput relative to inclusions (up to 0.5 cm) that they can pass. They differ in mobility, because they are installed in different locations. When buying, you should pay attention to the length of the hoses (usually it does not exceed 7 m).

Semi-submersible fecal pumps are also limited in the size of missed impurities. They are located in the liquid at the bottom on a special float that controls their location.

Submersible fecal pumps are completely lowered into the pumped liquid. They have a float for the level of drains. Fecal submersible pumps are the most common in production and in everyday life. Their main advantage is that they do not create noise and vibrations that negatively affect the human body. Waste containing fibrous and solid particles is pumped out with this equipment.

Models with a cutting mechanism have an advantage. A faecal pump with a shredder can grind organic impurities to a homogeneous mass. This facilitates the transportation of wastewater. The types of cutting knives are as follows:

• the impeller itself with the cutting edge;

• the design has a two-bladed knife with blades located perpendicularly;

• three blades that are pressed against a special membrane.

The impeller is the cheapest chopper option, but the productivity of pumps with it is the lowest. The disadvantage of such fecal pumps with a shredder is that the impeller has a hole in which water and feces enter. Its size may be small and therefore large particles may not be pumped. Such fecal pumps with a cutting edge are suitable for closed pits in which drains from the washbasin, bath, shower and toilet.

The knife, if there is one, is in front of the hole into which water and particles enter. It rotates clockwise, and its sharp ends ground everything before entering the holes. Such devices are not afraid of thick liquid. They are not afraid of open pits, increased content of sand (lumps), as well as paper (cigarette packs), napkins, personal hygiene items, etc.

The disadvantage is that if the fecal pump with the shredder will be constantly in the pit, you need to grind the knife after a year and a half. The working power of fecal pumps with a knife for uninterrupted operation must be at least 1100 watts.

A knife with a pair of blades located perpendicular to each other is more reliable and productive.

However, the most advanced is the combination of three cutting blades and a perforated disc. Passing through such a chopper, solid fecal fractions turn into a homogeneous ground mass.

The grinding mechanism works for both feces and many organic components. Among the organic substances that it is able to crush:

• sloon leaves, grass and other plants.

• food waste.

Most people who have a private house are suitable for sewage pumps with a cutting edge. But for a farm, or an open pit, you need to take a fecal pump with a knife.

How to choose a fecal pump?

Indicators should be taken into account when choosing a fecal pump: 

The first is the operating temperature of the pump, that is, the temperature of the drains.

Pumping equipment for sewerage can be calculated:

• to work only with cold and warm water up to +45°C;

• designed for pumping effluents with temperatures up to +90°C.

For pumping water from the cellar and fecal impurities from the street septic tank, a pump of the first category is sufficient. But for uninterrupted operation as part of the forced sewerage with a mass of plumbing in the house, you will have to choose a model from the second group.

Automation, shredder and body material.

Constantly monitoring the condition of the fecal pump and managing its operation manually means irrationally wasting your time. It's always full of other activities. Therefore, the equipment should be immediately selected with a float and a thermorelay.

The first will control the level of drain in the pit (from where it is pumped out) by turning off/on the device as needed, and the second will prevent the electric motor from overheating.

Some fecal pumps are able to handle solid waste and pebbles without a chopper. But only the presence of a cutting mechanism guarantees such equipment a long service life.

According to the material of the body, it is best to choose a pump for pumping sewage from metal. Stainless steel and cast iron will last many times longer than plastic. This nuance is especially important for immersion equipment, which is constantly in aggressive dirty waters.

Lifting height, power and power supply.

The higher the performance indicated in the passport, the faster the fecal pump pumps the sewage. However, it consumes more electricity. A cesspool in the country is rarely made voluminous, so a low-power unit is often enough to work at the summer cottage. He pumps out the drain not in 5 minutes, but in 20 minutes, but there is no hurry.

The optimal version of the fecal pump for a summer cottage (small house) with a power of 400–500 W. This is the productivity in the region of 140-160 l/min. Such performance characteristics will make it easy to cope with the pumping of sewage from the drain or cesspool, and with getting rid of excess water in the cellar.

The pressure figures show the maximum height by which the pumping equipment through the pressure pipe is able to raise the liquid with the feces. But when calculating this indicator, it is necessary to take into account not only the vertical section of the highway, but also the horizontal one.

In addition, it is affected by atmospheric pressure, the material of manufacture and the cross-section of the pipes. As well as the temperature of the drains and the size of impurities in them. In the simplified calculation of the required pressure, the meter of the horizontal section is divided by ten and added to the length of the vertical segment of the pipe. And then all this increases by 20-25% – the resulting figure should be less than the one indicated in the technical passport (+).

Some models of sewage pumps are designed to be powered by a single-phase network, while others are powered by a three-phase network. The first ones are cheaper. As a rule, it is recommended to choose such a fecal pump for giving. It will cause fewer problems with connecting to the power grid. And if necessary, it can be powered from a portable generator.

The effect of the shredder on the reliability of the sewage pump

A garbage shredder mounted at the pump inlet (rotating on the same shaft with an impeller) is more often used in small submersible fecal pumps. In the private sector, for example.

The decision is a bit controversial. First, there is a high probability of winding threads or other fibers on different elements of the structure up to the complete blocking of the shaft rotation. Secondly, the shredder mechanism creates a liquid flow resistance, which negatively affects the overall efficiency of the pump.

Fecal pump efficiency criteria

People around the world are concerned about energy conservation, reducing greenhouse gas emissions, global warming, and other related issues. Even if you are not one of them, you are probably not indifferent to the numbers in the electricity bill and you will want the sewage pump to consume as little as possible.

And here lies the first conflict - in most cases, by increasing the "non-coverability" of the fecal pump, the designers sacrifice its energy efficiency. In other words, a sewage pump with a more "non-beat" design has a worse hydraulic efficiency (Efficiency). Almost always. That is, in general, there is a choice:

Put less uncluttered fecal pump and will be lower electricity fee when it works normally. But more often you have to tolerate stops due to clogging, pay for cleaning the device (or often perform this not very pleasant work yourself).

Put a more uncluttered fecal pump, spend on electricity when it works normally. But save on cleaning the device (and your nerves, of course).

And the task would be simple if someone could say exactly how often in specific conditions each individual fecal pump would have to be cleaned. Then, with the help of simple mathematics, it would be possible to add up the costs of electricity and the maintenance/cleaning of the sewer pump and choose the best one.

But that doesn't happen. Not only that, these are two extremes - when the fecal pump works normally and when it is clogged. And imagine the situation - the sewer pump is partially clogged, but somehow copes with its function. The energy consumption in this case will be much worse than with the normal operation of the fecal pump. And it is not known exactly how much it will consume then.

As for the measure of "non-beatability" of sewage pumps. Is there a unit of measurement of "non-clumming" of fecal pumps? The answer is "No, it doesn't exist!"

One way to increase the "non-weaveness" of the fecal pump is to increase its free passage so that larger objects can pass through it. In practice, it is considered equal to the maximum size of a solid ball capable of passing through a fecal pump.

Therefore, manufacturers of sewage pumps, which have taken this way of increasing the "non-seizureness", are trying in every possible way to impose on consumers the size of the free passage as a measure of the "non-beatability" of the pump. It's so beneficial for them. But not to consumers.

Increasing the free passage is not the only way to increase the resistance of a sewage pump to clogging, and its size is far from the only factor that affects how the fecal pump copes with pollution.

There are a bunch of examples where a fecal pump with a large free passage will be clog and a sewage pump with a smaller free passage will work fine. Therefore, you need to see what design solutions are used in the hydraulic part of fecal pumps.

Overview of some brands of fecal pumps

The modern market opens up wide horizons for the choice of fecal pumps equipped with shredders. Imported products are present in large quantities on the modern market. The main suppliers of fecal pumps are German, Italian, Spanish companies.

Grundfos. Among the best manufacturers in the first places of the rating. The Germans have succeeded in the development and production of pumps for various purposes. It was not without German ideas and in the production of fecal equipment with a shredder.

Their Grundfos Seg fecal pump model, created for professional use, is well suited for an ordinary private household. Despite the cast iron body of the device, it is easy to transport from one place to another.

The electric motor is equipped with a sensitive system of protection against overheating and short circuits. There is a speed controller for the rotor of the electric motor. With a maximum operating power of 0.9 kW, it gives a pressure of at least 15 m. It is immersed to a depth of 10 meters.

Hertz. The next best representative of liquid pumping devices is another German invention, this time from Herz. The WRS25/11 model is in high demand due to reliability, durability, wear resistance. A special feature is its use in extreme conditions.

Fecal pumps of the German manufacturer Herz attract with excellent operational qualities, practicality and a wide range, which allows you to choose equipment for pumping of any volume

The Fecal pump from Herz provides a productivity of up to 260 l/min, creates a pressure of up to 14 m and can be submerged to a depth of 8 meters. The weight of the device is 31 kg due to the cast-iron body and steel working parts. The winding of the electric motor has an insulation class of "B".

A powerful device from the Italian manufacturer is the Calpeda GMG fecal pump with a shredder with a self-sharpening mechanism. Equipment, the service life of which depends only on the natural wear of parts. The fecal pump with a self-shrening shredder is designed for operation in extreme conditions. The design allows immersion to a depth of up to 20 meters. During operation, a pressure of up to 40 m is created. The performance indicator is 16 cubic meters per hour.

Conclusion

In conclusion, we can say that the fecal pump is an important element of the sewage system for objects without access to the central sewer. The correct choice and operation of the sewage pump ensures the effective and reliable operation of the entire system – it is the basis of a comfortable life in a country house, cottage or other building.

What fecal pump to put? If there are definitely no long solid objects in the wastewater, it is best to put a sewage pump with a channel or screw impeller.

Long solid inclusions are provided – it is more profitable to take a pump with a half-open impeller.

It is necessary to pump very problematic wastewater at any cost, with which a semi-open impeller is not able to cope – a sewer pump with a vortex wheel will be the only possible choice.

Only food waste, and human waste products get into the sewer, and threads, rags and similar things are guaranteed not to get into the sewage - you can use a pump with a shredder at the inlet.

Housing material – it is better to choose a metal fecal pump – it will last longer (especially the submersible fecal pump).

For a country house, it is better to choose a device powered by a single-phase network.

Long solid objects are plastic bottles, beverage cans, chips, thin branches and similar things. Steel reinforcement can damage any pump if it gets into it.

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What can a fecal pump?

Fecal pumps are usually used to pump out fecal sewage. It is a thick liquid, a viscous mass. Often contains fibrous lumps of wool, hair or tissue.

How long can a fecal pump work?

Standard fecal pumps are designed for a maximum frequency of not more than 20 per hour with a service life of no more than 3000 hours between maintenances.

Is it possible to pump clean water with a fecal pump?

Fecal pumps are used to remove heavily polluted water from cesspools, septic tanks, storm sewers. They also pump clean water.

Can I turn on the fecal pump without water?

Pump manufacturers indicate that the operation of the pump without liquid is not allowed.

The "dry move" is easy to identify if the device is disassembled. It does not apply to the warranty case!

Can a drainage pump be used instead of a fecal pump?

Fecal pumps are capable of pumping hot liquids. The drainage apparatus is not designed for this. A fecal pump is used instead of a drainage pump. But vice versa can not. Since drainage pumps will not cope with the task.

Which hose is better for the fecal pump?

Since these devices pump out dirty and viscous liquids, it is necessary that the nozzles can withstand a pressure of ≥ 6 atm. It is recommended to use reinforced or corrugated sleeves designed for 8-25 atm. With a large inner diameter (25 mm, 32, 40, 50).

Can a fecal pump be used for irrigation?

If the source is very polluted, a fecal pump with the ability to pump even sludge is used.

What is the difference between a drainage pump and a fecal pump? What is the difference between a fecal pump and a drainage pump?

The mechanism of the drainage pump passes all the water through itself. Fecal pumps pump out the liquid through special nozzles. They are installed in different parts of the equipment and ensure the transportation of effluents. Through the outlet nozzle, the system releases contaminated liquids.

The drainage pumps out water, which may contain solid particles - small pebbles or sand. But the size is no more than 5-12 mm. The fecal pump pumps liquids of thick, discous, turbid or oily texture. But not with small solid particles.

How long can a fecal pump work?

Standard water disposal devices are designed for a maximum frequency of inclusions ≤ 20 per hour with a service life between maintenance of no more than 3000 hours.

What types of fecal pumps are there?

Immersive. Fully in the working environment.

Semi-immersion. The suction part is located at a considerable distance from the electric motor.

Superficial. The device is located next to the tank and is connected to it by a hose, which is immersed in the liquid.

What is a fecal pump for?

In addition to transporting sewage, such pumps are used to remove the contents of septic tanks and cesspools, clean from silty sediments, pump downpour ditches, etc..

How to store a fecal pump in winter?

It is necessary to store the fecal pump in a room that excludes precipitation and has an air temperature of at least +5 ºС.

How to fix the fecal pump?

The device is placed on the bottom of the pit when we know that it is hard and even. This will allow you to reliably install a fecal pump – there will be no skew, and there will be no fall. If the surface quality is questionable, the device is suspended on a strong steel or nylon cable at a distance of ≥ 15 cm from the bottom.

What is a fecal pump with a chopper?

It is used in sewerage networks into which extraneous solid particles or other high-density substances can fall. It grinds solid impurities, pieces of plastic, small products made of tin metals, hygiene products that get into the toilet.

But it must be borne in mind that fecal pumps cannot cut stones and other rigid inclusions. A chopper is a sharp paddle knife (or knives) (like a meat grinder) at the inlet of the pump unit. The knives are launched when the membrane is affected by a viscous fecal mass.