In the refrigeration business, we focus on two areas of mediums used for heat transport. The coolants who are the “secondary refrigerants” like brines and glycol. You find them in low temperature applications and especially for the use in more complex piping networks. Most of the time regular centrifugal pumps are in use for this area.
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For colder applications [-40°C; frozen food processing; freezing; deep temp. storage], the refrigerant fluids generally employed are ecologically harmless “primary refrigerants” such as CO2 or ammonia.
This article is about the selection of these related primary refrigerant pumps.
Because these liquids [CO2 and ammonia] are dangerous to people if leaked to atmosphere, pumps have to be sealed in a special way. One way is the use of a “canned” motor-pump, the other by using a magnetically coupled pump.
Canned motor-pumps have been very popular of recent times because of their safety and the higher cost of “mag-drive” pumps. There are also several high quality manufacturers of these pumps. The canned motor pump has a hermetically sealed casing around the motor, which is directly coupled to the pump. There is therefore no need for mechanical seals and the chances of a leak is very minimal. The only draw-back of this design is that pumped fluid needs to pass through the motor chamber to keep the motor cool, therefore using part of the motor’s energy to provide this function.
Over time, the cost of magnetically coupled pumps has reduced, and German pump manufacturer, EDUR, has produced a line of refrigerant pumps using this principle.
Firstly, off the shelf, mass produced TEFC motors can be utilised in lieu of specialist motors used in the canned motor-pumps. And because of the spatial separation between motor and pump, heat transfer into the medium is reduced or avoided, benefiting the energy balance of the system. Finally, and most importantly, because energy is not being used to pump fluid over the motor, EDUR pumps are more energy efficient – a benefit when pumps are running 24 hours per day, 365 days per year.
Any pump used in refrigerant systems needs to have a low NPSHr (Net Positive Suction Head required) because the pumped fluid will always be close to its “boiling” point. It is also best if the selected pump is able to handle certain levels of gas content.
Both canned motor-pumps and EDUR magnetically coupled pumps have low NPSHr, but because of their “diffuser devices”, EDUR pumps handle some evaporation of refrigerants reliably.
The EDUR Torque-Flow (FUB) range of centrifugal pumps have vortex impellers and are capable of handling spherical solids up to 80mm in diameter. They are close-coupled and available with casings of Cast Iron, Ductile Iron or Gunmetal Bronze, impellers of Ductile Iron, Gunmetal Bronze or Stainless Steel, with Stainless Steel shafts (in 2 grades). Some models are available in all Stainless Steel construction. Abrasion-resistant protective linings of ceramic and polyurethane are also available.
Advantages include:
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The EDUR LBU multiphase pump is a multi-stage centrifugal pump with the unique capability of being able to pump a liquid/gas mixture. The centrifugal pump is constructed of either C.I./ Bz/ SS, Nodular Cast Iron, All-Bronze, Stainless Steel, or Super-Duplex Stainless-Steel construction, so may be used to handle a variety of liquids.
Air, Oxygen, Carbon Dioxide and Ozone gases can be introduced into the suction line and transported and used to mix or disperse the gases. This makes the pump ideal for DAF plants, where the multiphase pumps provide the task of air saturation without the use of compressed air (no compressor, air saturation tank or associated controls).
Advantages include:
Designing pumps since , EDUR Pumpenfabrik has developed a range of pumps for use in refrigeration systems. They have been designed to provide a maximum level of safety, reliability and efficiency. They are the safe option because they use standard TEFC motors, which don’t need to be cooled using the pumped media. They are efficient because they use magnetic couplings. By using magnetic couplings energy is not wasted by pumping fluid over the motor [as with “canned motor pumps”] and back through to the separator.
Advantages include:
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Hydro Innovations is proud to distribute a broad range of quality, reliable and industry-leading industrial pumps and aerators.
We are also delighted to share that Hydro Innovations is proud to be the exclusive distributor of Gorman-Rupp Pumps.
Gorman-Rupp is the world leader in self-priming centrifugal wastewater pump technology, and invests heavily in R&D, and in training for their international representatives – like Hydro Innovations.
This puts us in an excellent position to make the very best recommendations for our Australian customers.
Our other suppliers, Ragazzini of Italy and EDUR of Germany, are also world leaders in their respective technologies (Peristaltic Pumps – Ragazzini, and Specialist centrifugal pumps – EDUR).
We carry a very large inventory of pumps and spare parts for all of these brands, to help us to deliver industry-leading service.
Both novice installers taking their first steps in the industry and those who have some experience in the profession but are starting out on their own for the first time face a dilemma: how to choose a vacuum pump to meet all the requirements when working with stationary air conditioning systems.
There are several issues to consider when making this choice. Since vacuum pumps are one of the basic tools used by the installer of air conditioning and refrigeration systems, often used in harsh conditions and for many years - it is necessary to think carefully about the criteria that should guide their selection. In the following overview, we point out the basic parameters that we should take into account when choosing a vacuum pump, starting with the formal requirements and ending with its weight and dimensions.
The f-gas regulations impose a number of formal requirements on personnel performing operations with controlled substances and refrigerants, including the need to have a whole set of specialized tools on their equipment, which must meet certain requirements. In the case of a vacuum pump, it is required to be able to achieve a pressure equal to or less than 270 Pa. So, when choosing this tool, check whether it meets this requirement.
Performance - this element will have a significant impact on the time we will have to spend on the procedure for drying the refrigeration system, commonly known as "vacuuming". The higher the pumping speed, the faster the process will be and therefore the efficiency of the entire installation will be higher. Here, therefore, we should consider whether a single-stage pump (which allows us to achieve a pressure of 0.02 mBar) or a two-stage pump (which allows us to achieve a pressure of 0.002 mBar) will suffice for our needs. A single-stage pump will be good for small A/C systems, but a professional should consider a two-stage pump, which is faster and allows a lower vacuum.
Unfortunately - in general, the higher the capacity of the pump, the greater the weight and dimensions, which in turn causes a deterioration in the ergonomics of work. Especially when we have to work with the pump in a hard-to-reach place, at height, on the roof - the greater weight and dimensions become a factor that significantly worsens working conditions. Therefore, you should always look for the golden mean between these two elements: performance and the size of the device.
The end vacuum generated - in addition to efficiency, is one of the key parameters to pay attention to when selecting a pump for air conditioning service. While usually the smaller and cheaper single-stage device allows achieving a vacuum of 150 microns, two-stage pumps allow achieving a final vacuum of 15 to 20 microns, which, of course, guarantees to achieve a much better cleanliness of the system before it is filled with refrigerant and thus guarantees a better and trouble-free operation of the air conditioning system.
Seemingly insignificant parameter, but which significantly affects the ergonomics of work. In a situation where you will have to climb a ladder to a scaffolding or the roof of a building loaded with a whole set of tools - you will notice how important this parameter is and how it significantly affects the quality of your work.
Additional equipment in the form of a vacuum gauge and a solenoid valve has become standard on pumps currently available on the market. Observation of the vacuum gauge readings allows you to monitor and evaluate the progress of the vacuuming process in real time, while the solenoid valve prevents the refrigerant from backing up into the pump after it has stopped.
Given the large and growing popularity of air conditioning systems, the availability and popularity of the tools needed to install and service them is also growing. Thus, there is a large selection of vacuum pumps from many manufacturers on the market. Among them are many brands that are strongly recognized for their great traditions, such as REFCO, ELITECH, MASTERCOOL, VALUE.
In our offer, every installer is sure to find the right tool for him - from single-stage pumps at a lower price and smaller size - suitable for the user who uses this tool relatively rarely, to two-stage pumps with high efficiency for the serviceman of large systems for whom the pace of work and the guarantee of obtaining very good parameters of the final vacuum are important.
Are you interested in learning more about refrigeration pump suppliers? Contact us today to secure an expert consultation!