VACUUM

Choosing the right vacuum pump for your needs:

When it comes to selecting the correct vacuum pump for your application there are a number of issues that need to be considered. There is a vast array of vacuum pumps available: Rotary Vane, Diaphragm, Screw and Turbo pumps, just to name a few. The two main specs required for selecting the correct pump are the vacuum level and the flow rate. Once these have been established the range of pumps available for your application will be less confusing.
 
The next thing you need to look at is the application itself. Is it a clean room application? Is it a large industrial job where there is plenty of water vapour?
 
These elements need to be discussed and considered carefully. The next subject is the material of the pump. Some applications are subject to a high amount of corrosive or acidic vapours, so Teflon or stainless steel will need to be a major component of the pump. Some pumps however cannot offer a high grade of protection so a special type of oil is required. This is the case with rotary vane pumps.
 
Power supply is another important aspect. This can be single phase, three phase, DC supply; sometimes even frequency converters are necessary.
 
It is important that you also consider the type of protection required. The pump could be in a hazardous area, which could possibly cause an explosion if the motor is not of the correct protection class.
 
As you can see there are a number of variations and performance elements that need to be taken into account when selecting a vacuum pump for your next job. If you are unsure about what is available or need assistance then please contact us for expert advice.

Continuous duty. Vacuum pumps available cover the range all the way from the highest quality European laboratory vacuum pumps all the way down to our budget and very economic vacuum pumps from as low as $395.00. A $395.00 vacuum pump can run forever, at or near, maximum vacuum pressure. However continuous duty at rough vacuum pressures increases exhaust vapour and reduces oil pressure. Coupled with any contamination from the application, the life of the pump will be reduced.   Price wise, it is at the lower end of the price/value ladder so expectations should be proportional to the price. A similar high quality laboratory or European manufactured pump could be around $5,000.  
 

Experiencing Poor Vacuum?

Ultimate vacuum will not be instantaneous. It is relative to pump capacity and system size. If it appears the rotary pump is not achieving high vacuum, check as follows:

Oil level correct when pumping.
All fitting hoses are tight and valves shut.

If no improvement is achieved, check with a known good McLeod gauge or digital electronic gauge. An adequate vacuum measurement for the refrigeration industry can only be determined with a good quality and accurate digital vacuum gauge. For general vacuum measurement and depending on whether the user already has refrigeration gauges and hoses (excluding the vacuum gauge), you could add on an independent dial vacuum gauge or if you do not have any of the above, buy a manifold with an integrated dial vacuum gauge. These would both also require some adaptors. This assumes a strictly DIY approach as professional installers would not use a dial vacuum gauge.

Alternatively, carry out the following procedure:

Remove pump from system.
Connect gauge to suction fitting positively sealed.
Run pump. A McLeod gauge should indicate a vacuum of between 50 and 1 micron. An electronic gauge will show approximately 250 to 20 micron after five minutes, depending on the type of pump.


Why your pump needs to be turned off correctly:


No vacuum pump should ever be turned off under vacuum unless the vacuum pump has an “Air-Admittance” solenoid valve attached. If turned off under a vacuum, the vacuum generator is left flooded with oil and can do damage on starting next time. There is no built-in non-return valve in the small two stage pumps unless advertised. Non-return valves are usually for power cuts only and even then a solenoid valve should be used as can admit air to the pump vacuum generator at the same time. The pump can be isolated using the regular refrigeration manifold & gauges and pump suction port hose loosened until pump pressure returns to atmospheric and can be turned off. Most single stage oil sealed vacuum pumps do have an "Anti-Suckback" valve but once again are strictly for the protection of the pump and the application but not intended to be a feature making it easy to turn on and off the pump !
 

Why your pump needs genuine vacuum pump oil:

It is extremely important to operate your vacuum pump using the correct viscosity oil, as those that are either too thin or too thick will cause damage and operational issues.

Oil MUST be changed when contaminated.

Oil contamination is usually indicated by poor vacuum reading, or a grey or milky appearance. Should liquids be accidentally allowed into the pump CHANGE OIL IMMEDIATELY. Your High Vacuum Pump is a precision unit and oil is less expensive than pump service and repairs.

We take pride in every Vacuum Pump we supply and ensure you of our long-term interest in our product's reliability. To ensure your continued satisfaction, Coolvac highly recommends the following oils for each model vacuum pump:

Product recommended oil for standard application

Vector RD90, 160, 320 All No 16 or Coolvac FDSAWS68

Javac CC45 and CC141 All Coolvac FDSAWS46

DD/CD 40 No. 15
DD/CD 75 No. 16
DD/CD 150 No. 16
DD/CD 300 No. 16

Cooling a recovery cylinder with your XTR Pro, Activa, or other reclaim unit:
Your XTR Pro or Activa Series recovery unit can be used to PRE-cool (or SUB-cool) the recovery cylinder if the head pressure is too high to complete the recovery process. This can occur when working with certain refrigerants with a high vapour pressure in high ambient temperatures.

If the recovery process stalls out because of high head pressure, stop the recovery unit, shut off the hose valves and reconfigure the setup as shown below. This can also be done before starting the recovery process but it may have marginal long term effect.
NOTE: This will only work if there is at least 5 kg of liquid in the recovery cylinder to develop the necessary pressure differential required.

Power on the recovery unit and rotate the discharge valve (V3) to achieve a pressure differential of at least 700 kpa between the LP gauge and the HP gauge. Keep the HP below 2500 kpa on the HP gauge to ensure that the HP cut-off switch will not actuate.

After several minutes of running, the cylinder will be cold. Power off the recovery unit and reconfigure the setup for normal recovery. Repeat as needed.
 
 

100% 
New Zealand 
owned & operated


Find out more about us

Sign up to receive special offers & updates


btn_signup.gif

Contact us

Free call NZ 0800 609 906
P: +64 9 415 9033
F: +64 9 415 9330
Email us on sales@coolvac.co.nz