Masdaf - End suction pumps (NMM)
The NMM pump is a single-stage, end-suction centrifugal pump in a monobloc design. Flow rate from 5 to 400 m³/h, head from 5 to 110 m, suction flange DN 50–DN 150, discharge flange DN 32–DN 125, speed range 1,500–3,600 rpm, medium temperature from −25 to +120 °C. The series complies with standards DIN 24255 and EN 733; the flanges are manufactured in accordance with EN 1092-2 and DIN 2533.
The NMM pump: what does ‘monoblock design’ mean?
In the monoblock design, the hydraulic assembly is mounted directly onto the motor: there is no separate frame for the pump and motor, nor is there an intermediate bearing assembly with its own shaft.
The motor is connected in one of two ways — via a motor shaft or a flexible coupling, depending on the model. The modular design allows for installation without a foundation slab.
Practical implications for installation. The NMM pump takes up less space than a frame-mounted version with the same flow rate, and does not require the pump and motor shafts to be aligned during installation — a procedure that, with the frame-mounted version, must be repeated after every overhaul. However, when the motor is replaced, the rotor support also changes; therefore, the motor is selected to suit the specific model, rather than being chosen arbitrarily.
The impeller is dynamically balanced in accordance with ISO 21940-11.
NMM Pump: Technical Specifications
| Parameter | Value |
|---|---|
| Type | centrifugal, end suction, monobloc |
| Levels | one |
| Capacity | 5–400 m³/h |
| Pressure | 5–110 m |
| Revolutions | 1,500–3,600 rpm |
| Suction flange | DN 50–DN 150 |
| Discharge flange | DN 32–DN 125 |
| Medium temperature | −25…+120 °C |
| Key dimensions and feed rates | in accordance with DIN 24255 and EN 733 |
| Flanges | in accordance with EN 1092-2 and DIN 2533 |
| Balancing the impeller | dynamic, in accordance with ISO 21940-11 |
| Connection to the motor | shaft or flexible coupling |
| Regulation | complies with the European Ecodesign Directive |
What does compliance with DIN 24255 and EN 733 mean?
Both standards specify geometry rather than quality: the main installation dimensions and the nominal flow rates and heads for end-suction pumps. EN 733 is a European standard, whilst DIN 24255 is an earlier German standard.
Practical benefits of equipment replacement. A pump manufactured in accordance with EN 733 has the same connection dimensions as a pump from another manufacturer of the same size class under this standard: centre-to-centre distance, distance between flanges, and positioning of mounting holes. Therefore, when replacing a pump on site, there is no need to modify the pipework or the foundation.
The same applies to the operating point: the standard specifies fixed nominal flow rates and pressures, so the size is selected from a table rather than from an individual manufacturer’s catalogue.
How to service the NMM pump
The back pull-out design means that the rotor, together with the impeller and cover, is removed from the casing from the motor end. The pump casing remains in the pipework; the flanges are not opened and the pipework is not dismantled.
In practice, this reduces the amount of work involved in replacing a seal or an impeller: the motor with the rotor is removed, rather than the entire pump. The NMM pump is also designed with common parts across the series, so the spare parts range overlaps across several sizes.
How does the NMM pump differ from the INM linear pump?
The difference lies in how the pump is positioned within the pipework.
In the series INM The suction and discharge flanges are aligned on the same axis and have the same diameter — the pump is installed in a straight section of pipework without altering the pipework layout. This is the in-line configuration.
The NMM pump has an end-suction design: the inlet is situated on the axis of the impeller, the outlet is perpendicular to it, and the flange diameters differ (DN 50–150 at the inlet, DN 32–125 at the outlet). The pump is mounted on a support, and the pipework is connected from two directions.
Selection rule. If the pump is to be installed in an existing straight pipeline and there is no space for a support, choose the INM model. If there is space for installation and a head of up to 110 m is required with a flow rate of up to 400 m³/h, choose the NMM model. In terms of flow rate, the INM model reaches up to 520 m³/h, whilst the NMM model reaches up to 400 m³/h; therefore, at high flow rates, the linear version covers this range.
Where is the NMM pump used?
The manufacturer classifies this range as part of building services systems.
The NMM pump is used in water supply systems for residential and commercial buildings, in heating, cooling and air-conditioning circuits, and in industrial processes.
The monoblock design is typical of a facility such as a pump room or plant room with limited floor space, where the pump is installed without a foundation slab and maintenance is carried out without opening up the pipework.
Selection and service from Steiner Ukraine
A deep-suction pump is selected to match the operating point, rather than the maximum performance. A pump selected with a head margin operates to the left of the point of maximum efficiency, consumes more energy and places an increased load on the seals and motor bearings.
We determine the design flow rate and head, the system resistance characteristics, the temperature and composition of the fluid, the available inlet head, the diameters of the existing pipework and the method of installation. Based on this, we determine the size in accordance with EN 733, the impeller diameter, the type of motor connection and the need for variable speed control. Next come supply, service and spare parts. Steiner Ukraine has been operating in the industrial equipment market since 2006.
The following helps to identify where energy is being lost in the existing system Energy audit of pumping stations. Other items — in the section Masdaf pumps and in the catalogue industrial pumps and hydraulic systems.
