Masdaf - End suction pumps (NM)

The NM pump is a single-stage, end-suction centrifugal pump mounted on a common frame with the motor. Flow rate from 5 to 3,500 m³/h, head from 5 to 105 m, operating pressure 10 bar, medium temperature from −25 to +120 °C, suction flange DN 50–DN 400, discharge flange DN 32–DN 350, speed range 1,000–3,600 rpm. The main dimensions comply with EN 733; the series also complies with DIN 24255; the flanges comply with EN 1092-2 and DIN 2533.

NM pump: the standard series of the end-suction range

The NM pump is the base model from which the other Masdaf end-suction series are derived. Hydraulic design in accordance with EN 733, frame-mounted configuration, connected to the motor via a flexible coupling.

Derivative versions change just one thing. NMM — the same as EN 733, but a monoblock design: without a frame or coupling, with a smaller overall size and a flow rate of up to 400 m³/h. NME — a heavy-duty mode in a different size range, with temperatures of up to 350 °C and explosion protection.

The NM pump covers the widest flow range in the series — up to 3,500 m³/h — at a head of up to 105 m and a temperature of up to 120 °C. This is the operating range for water and water-like media: where there are no high temperatures, no explosion-hazardous areas and no requirement for a stainless-steel design.

NM Pump: Technical Specifications

How does the NM pump differ from the NMM monoblock pump?

Both series are manufactured in accordance with EN 733 and have identical hydraulic geometry within the common size range. The difference lies in the drive configuration.

In the monoblock NMM, the hydraulic section is mounted on the motor: there is no separate frame; the shaft is either shared or a slip-on type, and no centring is required during installation. The overall dimensions are smaller, but the motor and pump form a single unit.

The NM pump consists of two separate units on a common frame, connected by a flexible coupling. It has a larger overall size and requires shaft alignment during installation; however, the motor can be removed and replaced independently of the pump.

Selection rule. By flow rate: there are no monoblock models with a flow rate exceeding 400 m³/h; this falls within the NM range. By installation location: if there is limited space in the pump room — NMM. By drive type: if a specific motor variant is required, for example one suitable for variable-frequency control or with a higher protection class, the NM frame configuration offers this flexibility.

NM pump: the benefits of a flexible coupling on a common frame

A flexible coupling transmits torque whilst also accommodating slight misalignment between the shafts and their relative displacement due to thermal expansion.

This has three practical implications. The motor can be replaced separately from the pump, without dismantling the hydraulic section. Vibration from the motor is not transmitted directly to the pump casing. Conversely, the axial load from the impeller is borne by the pump’s own bearing assembly, rather than the motor’s bearings.

The other aspect is alignment. The pump and motor are aligned during installation on the frame, and this procedure is repeated after every repair in which one of the components has been removed. Misalignment causes the coupling and bearings to wear out faster than any other factor, so it is checked separately during servicing.

Size series: EN 733 and ISO 2858

The Masdaf end-suction series features two different size ranges, which ensures interchangeability.

NM and NMM are manufactured in accordance with EN 733 and DIN 24255. In accordance with ISO 2858 and DIN 24256 — KYP and NME.

Both standards specify installation dimensions and nominal flow rates, so a pump within its own series can be replaced with an equivalent model from another manufacturer without the need to modify the pipework or foundation. Such a replacement is not possible between different series, as the dimensions differ. When replacing a pump on site, the first consideration is not the brand, but which standard the existing equipment complies with.

Where is the NM pump used?

The manufacturer lists water supply and booster stations; irrigation, sprinkler systems and drainage; the circulation of hot and cold water in central heating and air-conditioning systems; condensate pumping; industrial applications and public facilities.

What these applications have in common is water or a medium similar to water across a wide range of flow rates. It is precisely this wide range that defines the typical application of the NM pump: a single series covers both a small booster system and a main pumping station; therefore, at a site with several circuits of varying capacity, the equipment is standardised within a single series.

Selection and service from Steiner Ukraine

A range of 5 to 3,500 m³/h means that there are dozens of sizes within the series, and several of them technically fall under the same operating point. The difference between them lies in how closely the operating point falls within the zone of highest efficiency, and this determines energy consumption throughout the unit’s operational life.

We determine the design flow rate and head, the system resistance characteristics, the temperature and composition of the medium, the available inlet head, the diameters of the existing pipework, the standard of the existing equipment to be replaced, and the need for frequency control. Based on this, we determine the size in accordance with EN 733, the impeller diameter and the motor specifications. 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.