How To Get Maximum Life From Your Diffusion Pump Oil

Diffusion Pump Oil is one of the costliest consumables required by vacuum users. In the present day scenario of cut throat competition, engineers are under a lot of pressure to reduce costs without compromising on quality. Based on my experience of almost 20 years in the vacuum line, I have compiled a list of do's and don'ts as to how one can get maximum life from the diffusion pump oil. For the benefit of our valued customers, the facts are given below -

1.   Topping up at regular intervals is most important factor in getting maximum life from Diffusion Pump Oil. Care should be taken to top up the oil in the pump in a timely manner. In the absence of topping up, volume of oil in the Diffusion Pump reduces, whereas heaters keep producing the same amount of heat. This causes overheating and accelerated loss of DP oil. This further reduces the volume of oil, which in turn causes more overheating and loss of DP oil is further accelerated and so on.
Diffusion_pump
Diagram of Diffusion Pump

2.   Keep track of the water flow through the cooling lines. Check the inlet and outlet water temperature as well as the flow rate. Lines can become clogged or scaled over time. As Diffusion Pump oil vapor can only condense on coming in contact with cold walls of DP. Any reduction in cooling causes overheating and increase of pressure inside DP. This may result in loss of oil by back streaming.

3.   Strange as it may sound a very low fore- pressure can also cause loss of DP oil. This can be prevented by switching on heaters before fore pressure becomes too low.

4.   Faulty gauges for pressure/heater too, can cause accidental overheating of the oil or the oil not getting the required heating. Check that all the gauges are functioning properly.

5.   Silicone diffusion Pump Oils have a life of about 4 times that of Hydrocarbon Diffusion Pump Oils. Also Silicone Diffusion Pump oil does not blacken and clog the jets of DP so Silicone DP oil works out more economical in the long run.

6.   Poorly working Rotary Pump will put extra burden on diffusion pump. It must be ensured that Rotary pump is working properly to get full life from Diffusion Pump Oil.

7.   Do not expose the oil to air when it is heated. Doing so will affect the viscosity of the oil – it thickens and vacuum reduces. To avoid air exposure valves must be checked from time to time.

8.   To avoid having the oil migrate into the vacuum chamber, a cold cap should be fitted at the top of the nozzle assembly inside the diffusion pump. This cold cap condenses the vapor in that area.

9.   A concentric circular chevron baffle should be present at the mouth of the pump. It allows air molecules to wander in, but traps the heavier oil vapors as they try to escape.


11. Sometimes back streaming of contaminants from the vacuum chamber takes place causing the oil to form sludge. This is preventable by installing filters above the chevron baffle of the diffusion pump.

12.    Silicone diffusion pump oil starts to decompose if it comes in contact with even trace elements of alkali metals (e.g. hydroxides  of sodium, potassium, cesium etc.). If process requires use of these then care should be exercised to prevent them reaching silicone DP oil. 

13.  In processes like PVD, coatings requiring plasma or transparent metalizing, gas load can cause vacuum of diffusion pump to fall below 10-1Torr. This can result in back streaming of DP Oil or even stalling. This is preventable by reducing the process speed or increasing the capacity of backing pumps.

Connect With Us

Name
Email *
Message *


                                                               Written by: Anshuman Punj.






Go to Supervac Industries Website

 http://supervacoils.com/

Boron Nitride Powder: SV-BNP+ (Supervac Industries): Properties and FAQs

boron-nitride-powder-release-agent--coating-lubricant-SV-BNP-plus





Q1) What is the particle size of SV-BNP+?

Answer: The average particle size of SV-BNP+ boron nitride powder is 5 micron.

Q2) Is it water soluble?

Answer: Yes, SV-BNP+ can readily dissolve in water to form a smooth lubricious paint-like liquid. Quantity of water can be as per the user’s requirement. Thereafter it can be applied with a paint brush, roller or sprayed.

Q3) Can it be mixed with a solvent?

Answer: Yes, SV-BNP+ can be dissolved in any solvent if so required.

Q4) What is the purity of SV-BNP+?

Answer: SV-BNP+ comes with the purity >99%. This makes it suitable not only for high-precision, high-technology fields, but also for advanced research purposes as well.

Q5) What is the crystal structure of SV-BNP+?

Answer: SV-BNP+ boron nitride powder’s crystal structure is hexagonal.

Q6) We need good quality boron nitride powder for sintering. Can SV-BNP+ withstand high temperatures?
Answer: SV-BNP+ powder can withstand temperatures till 1800 degree centigrade in an inert atmosphere or under vacuum without losing any of its properties.


Q7) We are a thermoplastic compound manufacturer. Is SV-BNP+ suitable for us?

Answer: Absolutely. SV-BNP+ is added to thermoplastic compounds for adding thermal conductivity. SV-BNP+ dissipates heat while retaining electrical insulation properties.


Connect With Us

Name
Email *
Message *




Written by: Anshuman Punj. 







Go to Supervac Industries Website


 http://supervacoils.com/

   Click Here  

Boiling Temperature of Diffusion Pump Oil Explained





vacuum diffusion pump
A lot of confusion exists in the vacuum industry about certain things, for example-

·         What should the optimum temperature be set in diffusion pump heaters so as to get maximum level of vacuum in shortest possible time?

·         How can the temperature in diffusion pumps be set in such a way that the engineers are able to get maximum life from costly diffusion pump oil?

·         Is boiling temperature of silicone diffusion pump oil different from hydrocarbon diffusion pump oil?

Before attempting to understand optimum boiling temperature of diffusion pump oil, let us take a brief look about working of diffusion pump.

how does a diffusion pump work


http://supervacoils.com/rotary-vacuum-pumps-oils/


Since efficiency of diffusion pump depends solely on the working cycle of diffusion pump oil (diffusion pump has no moving parts) so this is evident that a higher diffusion pump temperature will mean a higher ultimate vacuum. Obviously a question comes to mind at this stage that why don’t we increase the boiling temperature to highest possible level. Answer to this is that increasing the temperature of diffusion pump oil involves financial implications (cost increase) because of the following reasons -


1.   Diffusion pump oil works in very difficult environment where there is vacuum and high temperature. So to increase the boiling temperature, superior (obviously costlier) oil will be required which is capable of withstanding these adverse conditions.

2.   At higher temperature O-rings and oil seals may give way so better quality sealing material is required (Costly again).

3.   For handling higher temperature, construction of diffusion pump also has to be stronger.

4.   For attaining higher temperature higher energy charges will be incurred.

5.   For obtaining higher temperature longer time is required so vacuum time increases.

Decision about boiling temperature is basically a balance between level of vacuum required and cost incurred. Our guideline in line with the established practice in the industry is as below -

      
S. No.
Vacuum Required
Temperature in Diffusion Pump
Supervac Products
Equivalent Products
1.
10-9 to 10-10 Torr
245oC
SV-SIGMA+
DC-705
Hivac F5
2.
10-7 to 10-8 Torr
220oC
SV-SIGMA
DC-704
CVC4
Hivac F4
Ulvoil D31
3.
10-5 to 10-6 Torr
180oC
SV-SIGMA FAST
DC-702

diffusion-pump-oil-lubricant-myths

Some myths are prevalent in the industry about diffusion pump oils. These are clarified as under-

Myth no.1: Boiling temperature of hydrocarbon diffusion pump oil is different from boiling temperature of silicone diffusion pump oil- This myth is baseless as boiling temperature of both hydrocarbon and silicone diffusion pump oil is same. For example- Well known hydrocarbon diffusion pump oils like Supervac SV-DELTA, Lion S, Ulvoil D11 and CVP300, all have boiling temperature of 220oC.

Myth no.2: My diffusion pump has been designed for hydrocarbon/silicone diffusion pump oil only- This is also false. You can use any diffusion pump oil (hydrocarbon or silicone) in any diffusion pump based on your requirement. For details about merits of hydrocarbon and silicone diffusion pump oil please read my blog post-http://supervacindustries.blogspot.in/2013/04/silicone-diffusion-pump-oil-vs.html


diffusion pump fluid-silicone-hydrocarbon

Myth no.3: My equipment manufacturer asks me to use only a particular brand of diffusion pump oil which is exorbitantly priced- Your equipment manufacturer is trying to fleece you. For details about equivalent vacuum oils manufactured by reputed and established manufacturers anywhere in the world please read our blog post at- http://supervacindustries.blogspot.in/2014/03/vacuum-oil-equivalents.html. In case you don’t find it there then please contact us. We will help you find an equivalent product.

Myth no.4: There is no need of topping up- Absolutely false and dangerous myth prevailing in the industry. Topping up at regular intervals is of utmost importance to get proper vacuum and avoiding damage to the equipment.

Myth no.5: Charging less diffusion pump oil in diffusion pump reduces vacuum time- Absolutely false. Charging less oil than required will cause back streaming, burning of diffusion pump oil and damage to costly equipment.

Myth no.6: My diffusion pump oil works at 170oC- Diffusion pumps do not work at temperature below 180oC. Your oil supplier is supplying you cheaper vapor jet booster pump oil.


Conclusion:-

Based on the information given above I am sure that you will be able to choose the right diffusion pump oil as per your requirement. For example- if level of vacuum required is only up to 10-5 Torr and equipment is old then hydrocarbon diffusion pump oil will work more economical. Similarly if vacuum level required is 10-7 Torr then there is no point in using SV-SIGMA+. Furthermore by using simple precautions like frequent topping up you can get a much longer life and value for money from your diffusion pump oil.

manufacturers and suppliers of vacuum pump oil


For more helpful tips about how to get your money’s worth from your diffusion pump oil, you can read my blog post- http://supervacindustries.blogspot.in/2013/09/how-to-get-maximum-life-from-your.html





Connect With Us

Name

Email *

Message *

Written by: Anshuman Punj. 



  







Go to Supervac Industries Website


 http://supervacoils.com/
   Click Here