The centrifugal cantilever single-stage pump can be multi-flow. Centrifugal and axial pump designs. Features of horizontal pumps

The most common type of water pump is centrifugal aggregates, depending on the design features classified into two groups: single-stage and multi-stage pumps.

In this article we will talk about their differences, structure, principle of operation, advantages and disadvantages. The range of products of the leading manufacturers of centrifugal pumps, Grundfos and Lowara, will also be considered.

1 Principle of operation and design differences

A centrifugal pump is an equipment that pumps a working fluid due to centrifugal force, which is created as a result of the rotation of a vane drum. Such units have a metal or steel case, inside which there is an electric drive and a rotation shaft. A drum is rigidly fixed on the shaft, which can be open (consists of one disk and side blades) or closed (two disks, between which the blades are located).

The drum blades are located at an angle, they are directed in the opposite direction to the direction of its movement, which is necessary to ensure the most efficient capture of water. On the body of the unit there are two nozzles - suction and supply (pressure), through which the pumped liquid circulates.

When the pump casing is filled with water, the drum begins to rotate, water enters the blades and, as a result of the movement of the wheel under pressure, is thrown to the discharge pipe. As a result, a zone is created in the area of ​​the outlet high pressure, while in the central part of the drum there is a vacuum zone, under the influence of which water will begin to flow through the suction pipe of the pump. This principle ensures a continuous supply of fluid circulation pumps any type. Unlike piston units, they do not have problems with uneven, pulsating pressure, which significantly expands the scope of this technique.

Consider the device of a single-stage unit:

1. The body, also called a snail (the diagram shows horizontal type case).
2. Impeller.
3. Sealing the working shaft.
4. Rotation shaft.
5. Oil bath chamber seal.
6. Bearing support.
7. Carrying support.
8. Holes for checking the oil level in the chamber.

Single-stage centrifugal pumps have one impeller, while multistage pumps have two or more. At the same time, their principle of action remains identical, only performance characteristics equipment - capacity (the amount of pumped water per minute) and head (the maximum distance to which the liquid can be pumped). The head is indicated in meters, which indicate the pumping distance in height, to find out maximum length transporting liquid, the pressure must be multiplied by 10.

Depending on the design device, a multistage centrifugal pump can be sectional or volute. The sectional unit differs in that the liquid is pumped sequentially - from the first drum to the next. The maximum productivity that a sectional pump can develop today is 900 m 3 / h at a head of 1900 m.

1.1 The device of a centrifugal pump (video)

1.2 Advantages and disadvantages of centrifugal units

Wide use pumping equipment, operating on the principle of centrifugal force, is explained by the presence of a number of operational advantages in this technique, which include:

• compact size and low weight due to direct connection a rotation shaft with a motor, the design does not imply the presence of any transmission mechanisms;
• reliability and durability, no need for regular maintenance;
• smooth supply of the working medium, zero risk of water hammer;
• the ability to work with contaminated liquids containing mechanical particles in the composition, which is achieved due to the absence of valves in the design;
• affordable cost due to the simplicity of designs.

The only drawback of these units is the relatively low efficiency when operating in low productivity mode. Especially critical this problem eases when it is necessary to pump a small volume of water under high pressure.

Also, as a disadvantage, the impossibility of quickly starting the equipment can be considered, since before starting pumping, the pump casing must be filled with water. In general, centrifugal pumps are the best choice for productive work.

2 Equipment classification

Both multistage and single-stage units, depending on the position of the impeller axis in space, are classified into:

• horizontal;
• vertical.

In a horizontal configuration, as a rule, large-sized industrial units are performed for fixed installation, also horizontal units are used in pumping stations automatic water supply, in which they are coupled with the accumulator housing. Vertical equipment is more common in the field of domestic use; all types of borehole pumps, drainage and fecal units are made in such a housing.

Also, one of the main factors in the classification of centrifugal equipment is its division into types depending on the position of the unit body relative to the pumped liquid, according to which pumps are surface and submersible.

Structurally, submersible equipment can pump up to 16 m3 of liquid per hour at a head of up to 200 meters. Almost all borehole pumps submersible, since they can lift water from a great depth (40 meters or more), while surface units, in principle, are not capable of sucking water from a depth of more than 10 meters.

Among the differences, we also highlight the fact that submersible installations are much quieter than surface ones, which is important during installation pumping station inside the dwelling. However, a surface pump is easier to maintain and repair as it does not have a completely sealed casing.

Consider the remaining classes of centrifugal equipment:

• depending on the developed supply pressure: up to 0.2 MPa - low, up to 0.6 MPa - medium and over 0.6 MPa - high pressure;
• by the coefficient of speed - quiet, normal and high-speed;
• by functional purpose - water, fire, oil, drainage, fecal;
• by the type of connection between the wheel and the engine - cantilever, drive, coupling.

The efficiency of operation of such units directly depends on their speed, wheel speed and design. So, compact single-stage pumps have an efficiency of 0.6-0.7, large-sized ones - 0.9-0.92.

2.1 Manufacturers and popular models

The world's leading manufacturers of centrifugal equipment are Lowara (Italy) and Grundfos (Denmark). Both manufacturers supply units to the market for both domestic and industrial use. The range of Italians includes five lines of pumping equipment:

While the Italian company specializes in multistage technology, the leading positions in the segment of single-stage units are occupied by pumps manufactured by Grundos. The company's range of horizontal units is represented by the JP series (which includes the popular single-stage Grundfos pump JP 5), vertical - series TP (standard equipment) and TPD (in-line pumps).

Single stage centrifugal pumps

Single-stage centrifugal pump is a kind of centrifugal pump, which is widely used for pumping water, liquids with high chemical activity, suspensions, emulsions in many industries. A pump of this type has one stage, that is, one impeller. A single-stage pump can have one or two-way fluid supply to the impeller. Due to the rotation of the impeller, the liquid entering the pump leaves it with an increased speed and increased pressure. Structurally, they are divided into horizontal and vertical single-stage centrifugal pumps. The latter have a vertical working position and create high blood pressure at the outlet compared to horizontal ones.
Single-stage centrifugal pumps are used for urban water supply, in industrial and agricultural water management, for irrigation of fields, pumping oil products, aviation fuel, etc.

CN MAG-M

Max. pressure 16 bar for standard weight and 150 bar for HP version (higher values ​​are possible on request). Used for pumping (explosive) hazardous, toxic media that interact with the atmosphere. There are no glands, external flushing systems, seals and valves, but ensures complete tightness even in severe operating conditions. Impellers closed type, statically and dynamically balanced, end suction. External ball bearings (L10).

The MZ series pumps with magnetic drive are manufactured from thermoplastic. Able to maintain a constant head over a wide range of pumping speeds. For use in chemical industry... There is a limited dry run capability.

The NZ series single-stage horizontal end suction thermoplastic pump is economical solution for pumping a wide range of chemicals. Mechanical seals single (TB / RA) and double (DROTT).

Cast-in horizontal single-stage pumps with end suction and side discharge and volute casing. Manufacturing material - thermoplastic. For pumping low density chemicals. Excellent for polishing, electroplating, filtration, cleaning and general chemical industrial applications.

NJL

The NJL series pumps are manufactured from PFA / FEP. End suction. They are an excellent alternative to expensive high-temperature alloy pumps for working with corrosive and toxic media (including acids). They comply with ISO 2858 / ISO 5199 / EN 22858. Mechanical seals, single and double. Roller bearings.

NJK

Cast pumps of the NJK series are horizontal single-stage centrifugal end-suction pumps. They are an excellent alternative to expensive high-temperature alloy pumps for pumping hazardous, toxic and corrosive media. Dimensions and construction comply with ISO 2858 / ISO 5199 / EN 22858. Mechanical seals, single (TB / RA) and double (DROTT), oil lubricated bearings.

NJRP

NJRP series horizontal cast end suction pumps are available with single (TB / RA) or double (DROTT) mechanical seals. The flow path is designed to withstand high loads and pressures on the flanges. NJRP series pumps are an excellent alternative to expensive pumps for pumping hazardous, corrosive, toxic media. Compliant with ISO 2858 / ISO 5199 / EN 22858 standards.

Cantilever centrifugal pump: volute casing of the pump; Working wheel; body support; front cover with suction pipe; - shaft; screw; ball bearing; stuffing box packing; - stuffing box bushing.

All existing centrifugal pumps can be divided into the following groups: 1) by the way of water drainage: a) simple (without a guide vane);

b) turbine (with guide vanes); 2) by the number of impellers: a) single-stage; b) multistage; 3) for water supply: a) with one-way supply; b) with a two-way supply; 4) according to the position of the shaft: a) with a horizontal shaft; b) with a vertical shaft;

When the device rotates, the fluid in the interstitial space is affected by centrifugal force, as a result of which water flows out from under the working stage. This contributes to the formation of a vacuum directly in the center of the stage, and also to an increase in pressure at the periphery. The liquid goes through the suction line and enters the pump through the nozzle. The movement of water in the suction pipeline is carried out due to the pressure difference in the central area of ​​the wheel and the intake basin. The liquid ejected from the impeller enters the volute, after which it moves to the discharge pipe, which is connected to the discharge pipeline. The larger the diameter of the impeller and the higher the rotational speed, the greater the centrifugal force and, accordingly, the pump head. An electric motor is used as a drive for the unit.

2. Multistage centrifugal pumps. Multistage pumps are designed to generate high heads. On common shaft rotating from the engine, several impellers are rigidly fixed through which the flow moves sequentially.To direct the flow from the outlet of the previous to the next wheel in the sectional pumps, a guide vane is used, it consists of 2 systems of blades, guides (located behind the impeller and reverse. For this purpose, pump designs have special channels or additional branch pipes in their bodies, which impairs the compactness. When the flow moves sequentially through the impellers, the pressure rises, at the outlet from the pump it is determined by the product of the pressure of one stage by the number of feet. There are horizontal and vertical. -x types of central nervous system

Depending on the method of supplying liquid to the impellers: single-threaded; multi-threaded.

By the method of removing liquid from the impeller: spiral (volute); turbine type.

By design of the case: monohull type; sectional type.

By the number of impellers: single-stage; multi-stage.

By the degree of speed: low, medium, high speed.

According to the drive method, the pumps are divided into: electric driven, steam (the drive is driven by extraction of steam from a steam turbine).

By the location of the shaft axis: horizontal, vertical,

By the type of application: mine, sewer, nutritional;

By the type of pumped liquid: acid, sludge, dredge, fecal, etc.

Single Stage Horizontal Pumps, API 610 (OH1 Configuration)

- Maximum head up to 160 m
- Working environment temperature: - 60 +250 ° C.

API pumps conform to OH1 configuration standard and feature a centrifugal, single-stage, horizontal, self-flushing foot-mount design. The pumps are designed for continuous operation in the chemical, petrochemical and gas processing industries.

Single Stage Horizontal Pumps, API 610 (OH2 Configuration)

Description and specifications

- Maximum head up to 380 m
- Working medium temperature: - 150… +450 ° C.

The pumps have a centrifugal single-stage horizontal design, with a suction inlet along the axis of rotation, a cantilever housing with a radial split and a coupling connection to the motor.

Construction and drawing

Single Stage Horizontal Pumps, API 610 (BB1 Configuration)

Description and specifications

Maximum flow up to 6400 m³ / hour
- Maximum head up to 180 m
- Medium temperature up to +160 ° C.

API centrifugal pumps are type BB1 ​​and have a centrifugal single-stage horizontal design, mounted on one axis, with an end-to-end split on the rotor axis of rotation and with impellers between bearing assemblies.

The main parameters of the pump

Single Stage Vertical Pumps, API 610 (VS2 Configuration)

Description and technical parameters

Maximum flow rate up to 10,000 m³ / hour
- Maximum head up to 150 m
- Working environment temperature: -30 +250 ° C.

API pumps are VS2 type and have vertical semi-submersible single stage centrifugal design... The pumps are designed to pump large volumes of liquid from containers over extended periods of time.

Single Stage Vertical Pumps, API 610 (VS4 Configuration)

Technical specifications

Maximum flow rate up to 1000 m³ / hour
- Maximum head up to 250 m

API centrifugal pumps are VS4 type and have a vertical semi-submersible single casing single stage centrifugal design.

Consumable characteristics

Horizontal multistage pumps, API 610 (BB1 configuration)

Description and specifications

Centrifugal pumps are technological horizontal multistage, axially split, with impellers located between bearing units, with one-way or double-sided suction at the first stage, with a double volute casing and supported along the centerline.

The pumps are designed to handle a variety of fluids with low NPSH, high flow rates and medium pressures.

Maximum flow rate up to 2000 m³ / hour
- Maximum differential head up to 650 m
- Working environment temperature up to +200 ° C

The main components of the pump

1 - Housing
2 - Impeller
3 - Wear rings
4 - the Main shaft
5 - Shaft seals
6 - Bearing housing
7 - Bearings
8 - Labyrinth end seals and deflectors

Multistage Horizontal Pumps, API 610 (BB2 Configuration)

Description and specifications

Centrifugal pumps are horizontal two-stage technological pumps with a diffuser at the first stage, with a radial split, with impellers between bearing units, with one-way suction, with a double or single volute casing and with a support along the center line.

The pumps are designed to handle a variety of fluids at low flow rates. Designed for continuous continuous operation in heavy duty use

Maximum flow rate up to 500 m³ / hour
- Maximum differential head up to 750 m
- Working medium temperature up to +400 ° C.

Design features

Frame... The tightness of the radial joint of the body, as well as its fixation with the absence of any displacements and guaranteed working clearances in the flow path, is ensured by the use of a metal-to-metal gasket with a fixed compression control in the radial connector. Supporting the casing along the centerline of the pump ensures that the casing is firmly fixed and prevents any displacement caused by thermal expansion.

Pump rotor assembly... The two-stage pump rotor is designed to handle specific fluids and operating conditions with maximum performance and is a pair of closed-type, single-suction impellers rigidly mounted on the shaft. Impellers and rotors are dynamically balanced.

Main shaft pump and rotor assembly are designed to minimize shaft misalignment, resulting in maximum term operation of seals and bearing assemblies.

Shaft seals... The horizontal pump design can accommodate any type of mechanical seal with all possible flushing plans in accordance with API 610.

Deflectors and replaceable labyrinth end seals in a centrifugal pump, they provide a guaranteed volume of oil in the bearing assembly and protect the oil from foreign mechanical impurities.

Multistage Horizontal Pumps, API 610 (BB3 Configuration)

Description and specifications

Maximum flow rate up to 1600 m³ / hour
- Maximum head up to 1500 m
- Working environment temperature: - 40 +210 ° C.

API centrifugal pumps correspond to type BB3 and, accordingly, have a multistage centrifugal horizontal design, with impellers between bearing assemblies, a casing with end split along the rotor axis of rotation and mutually compensated impellers

Pump flow parameters

Multistage Barrel Pumps, API 610 (BB5 Configuration)

Description and specifications

Designed for high pressure, high temperature, high speed, when working in difficult conditions in technological and industrial areas.

• Maximum flow rate up to 1100 m³ / hour
• Maximum differential head up to 5000 m
• Working medium temperature up to +400 ° C

API 610 grade BB5 centrifugal pumps, also known as “barrel pumps” due to their cylindrical outer casing, are high pressure pumps with three or more blades. As injection pumps in refineries, they create high pressure on the substances for pumping them into the reaction columns.

Design features of centrifugal pumps

Heavy-duty design fully compliant with API610

• Hull (double reinforced structure)... High quality stainless steel cylindrical forging provides the strength you need to safe work at high pressure at any temperature. Precision forging makes body parts more reliable than cast bodies.
• External enclosure Radially split metal-to-metal with compression control gasket ensures excellent seal without displacement and provides a hermetically sealed containment of high temperature and high pressure media.
• Inner body made with precision machining of a forged steel billet, which improves the final mechanical parameters - precision of machining, low surface roughness with a guaranteed strong metal structure throughout the body of the case.
• Rotor assembly An industrial pump is the basis of any rotating mechanism - first of all, it accumulates high technologies to achieve high performance and reliability.
• Balancing disc, reduces thrust to optimum levels and extends bearing life. The balancing disc, located behind the last impeller, reduces the thrust force on the rotor shaft caused by the impellers and thus reduces the load on the bearings.
• Main shaft Designed to provide minimal shaft misalignment to maximize bearing and seal life.
• Impellers (impellers) designed with the latest computer programs analysis of fluid dynamics in order to optimize performance and dynamic performance. The impellers are fixed to the shaft with press fits, split rings and double wrenches to minimize shaft vibrations and for balanced rotation.

1000 Number of stages in the pump Up to 20 Differential head, m 200 Applicable bearings Radial thrust and / or axial roller

Multistage Vertical Pumps, API 610 (VS6 Configuration)

Description and specifications

Maximum flow rate up to 1200 m³ / hour
- Maximum differential head up to 1500 m
- Working medium temperature from "-" 120 to +150 ° C

The main purpose of the API610 class VS6 pumps is the pumping of fluid substances with low temperatures, as well as extremely volatile and flammable substances in the oil and gas processing and petrochemical industries. For high pressure pumping, the pumps can have up to 20 vane stages. V vertical pumps high technology is also used to prevent leakage of hazardous substances and ensure safe, trouble-free operation.

Heavy Duty Pump Design and Specification

1 - Fastening the leading element
2 - the Coupling
3 - pump shaft
4 - Shaft seals
5 - Rotor
6 - Wear rings
7 - Inner sleeve
8 - Head
9 - Bowl
10 - External case
11 - the Bottom insert
12 - Column