Hydraulic Filling & top up for cooling / thermal management systems

Providing dependable, easy and neat top up and filling units for cooling and thermal management systems is essential both in production and in the field. The right fill unit ensures that people use the correct fluid, quantity and that it is clean. Avoid spills for specialist fluids.

Even water glycol which is used worldwide as a cooling medium needs to be dispensed carefully. Move to more specialist fluids and more complex cooling systems and you need a higher level of care. Consider using a dedicated Micropac pump/reservoir dispenser, the right size for the job and able to deskill the dispensing of the right amount of clean fluid when needed.

Specialist cooling and thermal management systems are big business. Whether it is a dedicated electronic device for a specific function that needs cooling or a massive data centre made up from thousands of systems, cooling keeps them running. Google tells us there are around 11,000 data centres in the world.

Why do you need to cool equipment?

Traditionally, internal combustion engines and electric motors might be considered the most common equipment needing cooling. Electric motors will either rely on heat sinks on the body or on forced air cooling using a fan. Heat is generated because a relatively small amount of the electric energy is converted to heat. Internal combustion engines may be air cooled or liquid cooled using water glycol pumped through passages in the block then through a heat exchanger which probably has its own air cooling. Marine engines can be cooled with raw water pumped through the engine or a closed loop of fresh water coolant and a heat exchanger to transfer the heat to the seawater. Internal combustion engines generate heat due to combustion process. This has to be removed from the vicinity of the combustion chambers. Because water freezes and corrodes, users add a glycol “antifreeze” additive that also retards corrosion. Glycol needs care in handling and disposal as it is toxic. There are plenty of other systems that need cooling, but a big driver for more sophisticated cooling are electronic components that can often generate heat that needs to be removed. You can’t let a system overheat, particularly if it is being used in a hot environment or intensively. Ultimately it will fail. Cooling these systems is a massive engineering challenge. Achieving this with a small space envelope and using minimal energy is the future.

When is air cooling not suitable?

Air cooling is simple and cheap. A plain heat sink using convection may suffice, maybe with forced air cooling using a fan or even the motion of a vehicle or vessel to force air over the surface for enhanced performance. Clearly, using motion to force air over a heat sink does rely on movement. Hence, a system could overheat in a traffic jam or on the runway. Fan cooling using air can be noisy but is very widely used. Some systems are unsuitable for air cooling, for example an underwater instrument pod if you cannot vent the hot air. Move to electronics and you will invariably pack components densely. Often, air cooling simply won’t work and you need to move to more sophisticated liquid cooling. If you have masses of electronics such as a data centre, Air cooling might well be impractical due to the sheer volume required.

Why use specialist thermal fluids instead of water glycol?

Specialist thermal transfer fluids are big business for good reason. READ MORE.

Users may opt for water as their thermal transfer fluid, with the addition of glycol antifreeze to lower the freezing point and provide additional corrosion resistance. On a domestic hearing system, additives to water may simply cut corrosion. For a more specialist system, a designer may opt for a fluid with greater thermal capacity, a higher boiling point and a lower freezing point. Boiling or freezing are both catastrophic failures in any cooling system.

The engineering of thermal transfer fluids is very specialist. Fluids include EGW (Ethylene Glycol and Water), PAO (Poly Alpha Olefin), PGW (Propylene Glycol and Water), Refrigerants, Fuel, Lube and Hydraulic Mineral or Synthetic Oils and Deionized Water amongst others. We have said before in our white papers that it is always essential to understand what type of fluid you are using in order to address properly materials, seals, safe usage and disposal. The first thing we do is download the MDSS and the data sheet. Where you have a significant problem is when a thermal transfer fluid or indeed a hydraulic fluid is proprietary and it isn’t instantly obvious what it is. Specifying the right seals is absolutely vital and sometimes this information can be mighty hard to find.

We can’t advise on applications for fluids. Tell us your proposed fluid and we can offer the pump solution.

Why use a Micropac top up or fill unit for my thermal transfer fluid?

You can configure your pump, reservoir and hoses precisely as you require from our catalogue parts. Our equipment was designed 40 years ago with soft seat and poppet valves to provide a capability for very low viscosity fluids. We can offer a range of different seal compounds within our standard seal housings and low corrosion is a big feature. All our equipment is manufactured in our factory in the UK and is serviceable, with low cost spares available.

How do I configure the right Micropac pump for my cooling or thermal control system?

It is vital to get the right system for your application. READ MORE.

Fixed system built into the kit or a carry around portable to service lots of units? Some users do run with a hand pump and fixed reservoir integrated into a specific system. Fill the reservoir with your thermal transfer fluid and refill or top up as required. A Micropac pump mounted on a fixed reservoir is neat. The little MPF top up units are very compact and offer reservoirs up to 2 litres. For larger volume systems, look at our MW units which are available with reservoirs from 2.5 litres through to 50 litres. If you have gone down the route of configuring a small system from a range of parts from Swagelok, Parker and others, look at the system builder PPS hand pump. That is small, 316 and polymer for very low corrosion and good value.

Or a portable wheel around cart or a carry around portable? Again, system size is the starting point. We have configured the small MPF unit with a 2 litre carry-around filler and top up unit. That can service multiple systems using hoses with quick disconnects and be stowed safely when not in use. The displacements on the MPF range from 4.3cc per stroke to 11cc per stroke. A relief valve is fitted to limit the maximum pressure. Contact the factory to discuss using the MPF.

Our most widely used top up unit is the larger displacement MP series which mounts a MW series Micropac hand pump onto a portable reservoir. Displacements range from 12cc per double stroke through to 100cc per double stroke and carry around reservoirs from 5 litres up to 20 litres. The MP is also available with a neat 2 wheel cart with a reservoir size of 10, 20 or 50 litres. The cart includes hose stowage. There is also a four wheel 50 litre pull-around trolley in the MP series.

On large systems, we can offer our air driven DUO two wheel cart which uses an air driven pump for rapid filling. DUO carts include an integrated hand pump for precise adjustment of flows and pressure plus the security of having a hand pump if an air supply is not available.

Your system size is likely to be a key decider on the pump rather than the pressure, which is invariably low on cooling and thermal management systems. If your system is small, that steers you to the MPF pump or smaller versions of the MW. If the system is large, look at the MW units or even the DUO.

Materials and seal compounds will be governed by the barrier fluid and specific requirements of the application. The barrier fluid will have its own compatible sealing materials. Talk to the factory to discuss your requirements. Our pump materials are either anodised alloy and stainless steel wetted parts or 316 stainless and bronze. Hostile environments require the 316 stainless option. Again, talk to us.

There may be an overriding requirements such as a hazardous area and the need for one of our ATEX/IECEx handpump units in your cooling or thermal management system filler or top up pump.

Cleanliness is also a possibly specific requirement. We offer an in-line filter for our equipment.

Deskilling operation and making the procedure simple and repeatable is vital. Users frequently specify hoses as an inseparable part of what we supply. We have supplied clear tube tell-tales in hoses to ensure that air has been bled out before filling. Snap couplings (“quick disconnects”) can eliminate spillage during connection and also allow a number of systems to be topped up in a single session.

Sarum Hydraulics filling and top up pumps are based on our Micropac catalogue equipment, so we can offer you a cost effective and reliable solution. After over 40 years, we are the experts.