Which sewage pump should you choose? MSV? MSK? maybe MSV-R?
Dear customers, as a manufacturer, we offer you almost 100 types of sewage pumps divided and marked by us due to their design and purpose. Because we use other pumps for raw sewage containing solids (strings, pieces of materials, sand, etc.) and others for pumping dirty water (i.e. sewage and rainwater without their content), we divided the pumps into three groups based on the type of impellers used in them and into eight groups depending on the different sizes of solids that can easily pass through the pump. The explanation of the codes we use is below:
MSV – means a sewage pump with a Vortex impeller and a free passage under the impeller specified in the next part of the name: 15, 50 or 80. This size specifies the allowable dimension of the ball of a given diameter in millimeters, which should pass unhindered under the impeller blades. The exception are MSV-15 pumps, in which the ball size is less than 10 mm and should not be used for raw sewage. The small passage causes that they are often clogged with solids found in raw sewage.
MSK – means a sewage pump with a channel impeller and a passage through the impeller channel defined by the next part of the name: 80, 90 or 100. This size specifies the allowable size of the ball of a given diameter in millimeters, which should pass without difficulty through the impeller channel. The number of impeller channels is marked with the symbol “K + number of channels” (K1, K2, etc.). This is important when determining the operating environment of the pump. In raw sewage, single-channel impeller pumps work best because of the low probability of wrapping rags and fibrous materials. Rotors multichannels have higher efficiency but lower resistance to winding of fibrous materials, therefore they work better on mechanically treated sewage or rainwater.
R – designation of a sewage pump with a grinding device, whose task is to cut solids contained in the sewage into small pieces capable of overcoming the narrow gaps between the impeller and the pump body. Like the MSV-15, these pumps, due to the short distance between the impeller and the pump body, have lower pressure losses and can pump to higher heights than pumps with large passages with relatively low energy consumption. When choosing them, it should be remembered that the possibilities of cutting knives are limited in relation to many materials, which – although they should not – are often found in sewage (mops, diapers, wires, stones, etc.).
Pump code designation:
- Submersible pump Metalchem-Warszawa Spółka Akcyjna.
- Impeller type:
- V – Vortex, otwarty wirnik ze swobodnym przelotem pod łopatkami,
- K1 – channel, closed impeller with one channel,
- K2 – channel, closed impeller with two channels.
- Free passage of balls in diameter in millimeters (under an open impeller or through a channel in a closed impeller), not available in a version with a grinder. Designations: 15, 50, 80, 90, 100 and R – grinder.
- Engine power in kW (with approximate decimal places).
- Number of motor poles (indicates rotational speed: ~ 2900, ~ 1450, ~ 900, ~ 700).
- Pump head height at a given power:
- L – low,
- M – medium,
- H – high,
- No symbol means that there is only one version of the pump.
- * Optional version number:
- Z – with a hitch (for mounting on the autocoupling),
- P – with flexible hose connection,
- S – on the stand,
- K – with a basket.
Example designation MSV-80-124L-Z Submersible pump with Vortex impeller, free passage 80 mm under the impeller, 12.5 kW, 4-pole motor, low head, with hitch for mounting on the autocoupling.
It is possible to combine markings, e.g. MSV-80-24PK – sewage pump with a basket and a flexible hose fitting.
Old pump names and new equivalents
Ladies and Gentlemen, due to the continuous development of the company and the constantly growing number of sewage pumps, rainwater pumps and dirty water pumps we manufacture, we decided to change the names of the pumps and we moved away from the previously used series of types MS1, MS2, MS3 and MS5. Almost all models are still available for sale and service but at the moment they appear under new names that precisely define the purpose of the pumps and their basic parameters such as the type of impeller, the size of free passage through the pump or the lifting height H, M and L.
|No.||Old name||Present name|
Parameters vs costs in sewage pumps
By definition, pumps are devices used to transport fluids from a tank at a lower pressure to a medium at a higher pressure. The work they do is most often called: pumping, pressing or heading and from the last word comes one of the main parameters of the pump, i.e. head. Head [H] is usually expressed in meters of static pressure of the water column [m] or pressure units: technical atmospheres [at] or bars [bar]. Currency converter: 10m water column equals 1at, and 1at equals 0.980665bar. Pressure is closely related to the second most important pump parameter, i.e. flow rate defined as flow or capacity [Q] given in liters per second [l / s], liters per minute [l / min] or cubic meters per hour [m³ / h ]. Of course, the values of flow and pressure are very different depending on the types of pumps, their power, rotational speeds, operating conditions, etc., but also depend on the parameters of the fluid handled, such as density and viscosity. Due to the profile of our company, we focus on pumps that pump liquids with water flow parameters, but with the content of impurities in the form of sand, faeces, suspensions and other contents of domestic sewage, not exceeding the density principle of 1100kg / m³. Under the general name “sewage” or “dirty water” there are many different mediums that can be pumped, e.g.
- domestic sewage discharged from homes (toilets, showers, washbasins, etc.),
- process wastewater from production plants,
- wastewater from restaurants and food processing (often with high fat content),
- rainwater (rainwater, storm water, etc.) from roofs, streets, squares carrying with them e.g. leaves, sand, dirt suspensions from flushed surfaces,
- dirty water (containing a mixture of various biological and chemical compounds)
- recirculation water e.g. in sewage treatment plants,
- process water (treatment plants, production),
- liquefied sludge,
- liquid sludge,
- water with sand from sandstones,
- leachate from landfills or leachate from plots at treatment plants,
- and many other types of fluids.
The designs of clean water pumps, dirty water pumps and sewage pumps differ significantly in designs and parameters. The content of solids in liquids forces an increase in the width of the channels in the pump impeller and the gaps between the pump body and the impeller. This significantly reduces the hydraulic efficiency of the pump, but at the same time increases its resistance to clogging and breaks in work. Pump manufacturers compete in solutions that improve the hydraulic efficiency of pumps while eliminating problems with pump clogging and blocking. Among the many good proven solutions that have been known on the pump market for years, from time to time there are new, surprising ones, some described by producers even as groundbreaking. Unfortunately, many of these solutions are nothing more than a simple marketing procedure to justify the high cost of purchasing and then servicing the pumps.
The designs of our submersible (wet) pumps result from many years of experience of our designers and observation of the behavior of individual solutions in changing working conditions. And so, we can safely say that for raw sewage containing fibrous materials, pumps with an open impeller with a large free passage under the impeller, e.g. 50 – 80mm, are best, and for rainwater and mechanically treated sewage, pumps with channel impellers. At the same time, it should be remembered that the larger the channels in the impellers, the lower the efficiency of the sewage pump and the hydraulic losses must be compensated by greater pump power. For raw sewage without fibrous bodies, one can also use channel impeller pumps, and their main advantage is greater efficiency than pumps with Vortex impellers at the same value of energy drawn from the network. With channel impellers, apart from the size of the channels, e.g. 80-90-100mm, their number also matters. Certainly, the sewage pump with a single-channel impeller will be less exposed to wrapping garbage on the impeller than a pump with a multi-channel impeller. A pump with an impeller that has a passage of 80 or 100 mm will be more resistant to waste contained in the sewage than a pump with 25 or 40 mm channels.
There are of course many more reasons for the application, but fortunately you do not have to worry about it yourself, our experts will take care of everything while choosing the best equipment for you. By commissioning us to analyze your needs and choosing the right pump for wastewater, you will receive from us reliable information about the advantages and disadvantages of individual construction solutions, along with simulation of operating parameters such as pressure and expenditure at the expected pump operating point, power taken from the network, estimated operating time and approximate energy consumption. Catalog / calculation data in conjunction with the costs of consumable parts and service of our pumps determined by us will allow you to independently determine the most important economic parameter of pumps Pump Life Cycle Cost – PLCC
The total PLCC consists of the following factors:
- Cost of purchase,
- Periodic inspection costs,
- Structural resistance to mechanical damage or clogging of the pump (generating service costs),
- Service costs::
- The cost of spare parts (especially after a few years, impeller, pump housing, seals, bearings, etc.),
- The costs of replacing them (sometimes requiring specialized tools or authorized services),
- Parts availability (waiting time, shipping e.g. from warehouses outside of Poland),
- Device downtime (the need to hire a replacement for renovation or looking for costly solutions to balance pump downtime),
- Installation cost (pulling and lowering the pumps with specialized equipment or e.g. the need to empty the tank to lower the pump again),
- The durability of parts affecting service costs (frequency of their replacement), sometimes the low cost of spare parts is more important than increased wear resistance because several times more expensive part will not have equivalent durability and it is more profitable to replace e.g. the impeller more often than buy with increased hardness,
- Energy consumption, actually the most important parameter over a long period of normal pump operation (no downtime or repairs).
The cost of buying a pump – as a rule, pumps from reputable manufacturers cost more, we expect, and rightly so, higher quality and durability. However, we do not always have to decide on top-shelf devices with the best solutions, because in many cases we will not use their capabilities, and we will pay mainly for the manufacturer’s logo and expensive accessories that we do not need at all.
Durability – a factor taken into account when buying, we expect that for more money we will get a solid product that will serve us longer than its cheaper equivalent, and its failure rate will be lower. In this case, it is also necessary to take into account the wear of consumable parts, such as impellers, pump bodies, seals, bearings, etc., but also check how the product has been on the market for a long time and what the opinion of users is about it. Often, the technical data provided by the manufacturer are difficult to verify, through very different working environments for different users. For some, rags and mops will be a problem, for others gravel, sand, construction waste and for others an aggressive environment, e.g. high or extremely low pH. It is worth analyzing whether to buy a pump made of better, but much more expensive materials, or whether it is more cost-effective to regularly replace cheap components. Let’s not be fooled by the slogans “increased resistance to …”, “longer life …”, “reduced failure rate …” and a lot of other fancy passwords to ensure us that the product is unique. There are no pumps that cannot be damaged.
Energy consumption – the most visible parameter during normal, trouble-free operation of the pumps. Every user strives to reduce energy costs, so the practice is to meet the pumping needs with the lowest possible pump power values. This has its pros and cons. Advantages: smaller power allocation, smaller physical pumps (lighter, easier to install), lower power consumption from the network. Disadvantages: low power – pumps working in dense wastewater, often containing garbage, growing with fat or sludge need a proper starting torque, therefore Metalchem-Warszawa S.A. even for small home pumping stations, it recommends pumps of not less than 1.1 kW. At low power, we also deal with smaller pump passages, which may result in their clogging and downtime or expensive services (Metalchem-Warszawa SA does not use free passages less than 50mm for sewage), also the operating time of pumps with low capacity may be longer than pumps with higher power and efficiency, which will result in higher energy consumption per 1m³ of pumped sewage. If the pumps are selected by experts from our company, we can present you with simulations of individual solutions, types of pumps, diameters of the discharge pipelines and checking whether the use of pumps with e.g. higher power by 1-2kW will not save time and energy through shorter working times.