The shadow cast by the upcoming Achema is also falling on Grundfos. On a press trip, the company presented a large number of new pumps the energy efficiency of which is especially convincing. We have picked out some of the most interesting new developments for you in the following article.
Ever since the halogenated hydrocarbons favoured for a long time out of thermodynamic considerations were discovered to harm the environment, the industry has been looking for environmentally neutral concepts with a GWP (global warming potential) that is as low as possible. Here interest is focussed on carbon dioxide and ammonia, which are natural refrigerants.
CO2 has the lowest GWP; it is chemically inert, non-inflammable and harmless to people (except in extreme concentrations) because it is a part of the air we breathe. However, the discovery of CO2 as a new refrigerant is forcing technological systems to be appropriately adjusted, for one thing owing to the high operating pressure required. The requirements for refrigerant pumps are also changing.
The RC Series canned motor pump without a shaft seal was conceived specifically for pumping R744 (carbon dioxide) and boasts an output of between 0.2 and 9 m3/h. The RC can also be counted on to pump other refrigerants, such as R717 (ammonia), R134a, R404A, R407C, R410A and R507A.
The RC pump’s cylindrical shape is especially well-suited to high pressure applications because a single static O ring is sufficient as a seal between the pump sleeve and the motor housing. The stainless steel (1.4301) components with their thoroughly cylindrical shape and smooth surfaces also make it easier to insulate the pump – which is a great advantage, especially when they are used for low temperature applications.
The pump’s hydraulic system is designed in multiple stages for pumping media near the boiling point. The first chamber is larger, so the refrigerant flowing in by way of the suction port can contain a limited amount of vapour bubbles. In addition, all RC pumps are equipped with an inducer to improve the output when the medium contains vapour bubbles. A coarse filter in the inlet to the first chamber prevents metal chips or parts getting into the pump’s hydraulic system.
A key characteristic of the RC pump is its high level of reliability thanks to its robust design and its multi-stage unit optimised for refrigerant media. The pump is convincing because it is easy to use, compact in design and weighs only 24 to 35 kg. The energy efficient drive and hydraulic system keep operating costs down and allow very little heat to get into the medium.
Its external CUE frequency converter also enables it to operate without constant bypass and apertures. Moreover, it is designed to be easy to service, thus reducing down times. Thanks to its back pull-out design, the entire unit can quickly and easily be replaced by a lightweight service unit (approx. 20 to 25 kg). Very low inlet levels or NPSHR starting at 0.2 m mean that it is easy to integrate into systems and plants with low design heights. The RC version with weld spigots needs no counter flange and thus eliminates the risk of leakage, as well.
Solenoid pumps up to 180 m3/h
Grundfos is offering a design without a shaft seal for the multi-stage high-pressure DRN pumps up to a size of CRN 150 (maximum of 22 kW/maximum of 180 m3/h) with the Magdrive permanent magnetic coupling. A containment shell hermetically seals in any environmentally hazardous or otherwise critical media. Through the containment shell, an external magnetic rotor drives the internal rotor, which is in turn connected to the pump shaft. Grundfos is offering the Magdrive magnetic coupling for applications up to a temperature of +120 °C; an expansion for higher temperatures is in planning.
For example, a fibre producer uses a CRN Magdrive pump in the pre-product cycle to pump dissolved polyacrylonitrile in dimethylformamide (DMF is classified toxic and carcinogenic). Highly viscous polyacrylonitrile is the base material for producing carbon fibres.
Magnetic coupling pumps without a shaft seal give top priority to safety and environmental protection, yet here too energy efficiency should not be entirely left out of consideration. That is why looking at the Grundfos solution from an energy point of view is interesting. Conventional magnetic couplings lose up to 30 % of their energy – and the operator must therefore often choose a larger motor. CRN Magdrive pumps are much more efficient in this regard. Motors between 0.37 and 22 kW can be expected to lose only 2 to 16 %. Because highly efficient IE3 class motors are the stand-ard motors used in magnetic coupling pumps from Grundfos, they are considered to be particularly economical. The pump can also be arranged in an Atex or a low NPSH design. O-rings made of FXM (Fluoraz) or FFKM (Kalrez) are available for especially aggressive media.
Made of stainless steel
Grundfos has many years of expertise in processing chromium-nickel steel. This stainless steel is not likely to lose its outstanding importance in pump construction in the near future. Now the company is also offering NB series close-coupled pumps (NBE with frequency converter) in stainless steel (1.4408 or 1.4517; bronze impeller optional). These close-coupled pumps are conceived for applications in which large amounts of liquid must be pumped efficiently and reliably.
The maximum flow rate is 850 m3/h, the maximum head is 160 m (operating pressure of 16 bar). The manufacturer states a permissible temperature for the media ranging between -25 and +140 °C, the relative humidity of the surrounding air can be as much as 95 % (IP 65).
Important to the operator is the back pull-out design of the pumps; it enables their motor and impeller to be removed easily, without any extra work on the pump housing or piping. The entire motor and impeller unit can be removed separately, which considerably simplified maintenance. The pumps are equipped with IE2 (EFF1) motors as a standard feature, IE3 is available as an option.
The speed-controlled NBE variants with the Grundfos MGE high-efficiency motor up to 22 kW is ideal for saving as much energy as possible in plants with fluctuating volume flow requirements. The pump is electronically controlled, so it can be connected to a bus communication system. For power above 22 kW, external CUE series frequency converters can be used (for pump drives up to 250 kW). The user interface and functions of the two e-solu-tions, whether with integrated or external frequency converter, are identical and conceived especially for Grundfos pumps.
Hall 8.0, Booth K38