I've had the good fortune of being given a couple of MKS mass flow controllers by Santa. Unfortunately, they no longer work (according to the scribble on them they have 'no flow')
Does anyone have any experience of fixing/re-building these units?
They are analogue units
one is a 1479A the other is an 1179A
one has PolyChloroTriFluoroEthylene seals, the other has perfluoroelastomeric seals.
They have a maximum flow rate of 50 sccm and 200 sccm respectively, and were used for BCL3.
Any advice will be appreciated.
Re-building MKS mass flow controllers
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Doug Coulter
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Re: Re-building MKS mass flow controllers
As someone who used to make a living taking apart and fixing stuff with no data (back in the '60s), I'd say just take it carefully apart and use the old brain on it. It will probably be obvious at that point if you don't use so much force getting it apart as to break it badly. Either the seals swelled, the actuator froze, or it got full of some process gunk, there's not a lot else it can be, other than electronics, which you can test for fairly easily without taking it all the way apart.
These are far too large for fusor use, I am running on the close order of 0.1 sccm in my setup, and going for less all the time.
That is, unless you have an infinite, free, gas supply and a way to get it out of the room safely, and enough extra pumping to keep the pressure in range for fusor uses.
These are far too large for fusor use, I am running on the close order of 0.1 sccm in my setup, and going for less all the time.
That is, unless you have an infinite, free, gas supply and a way to get it out of the room safely, and enough extra pumping to keep the pressure in range for fusor uses.
Why guess when you can know? Measure!
Re: Re-building MKS mass flow controllers
I'm assuming, for now, that it is either the electronics or the solenoid that are malfunctioning.
The manual says these require +/-15 volts and +5 volts, I'm wondering if the +/-12 volts from an ATX power supply will be sufficient for the +/- 15 volt supplies?
It will go down to 0.5 sccm, and if I modify the by-pass, I think I can get it lower (the by-pass splits the flow, so only a small percentage goes through the sensor). I can also try running a lower inlet pressure, but the main purpose of the exercise is to strip these units and get them working.
I think it is unlikely that these are 'jammed up' with process gunk, as they will only have been connected to a BCL3 supply, and will have had non-return valves fitted downstream.
The manual says these require +/-15 volts and +5 volts, I'm wondering if the +/-12 volts from an ATX power supply will be sufficient for the +/- 15 volt supplies?
It will go down to 0.5 sccm, and if I modify the by-pass, I think I can get it lower (the by-pass splits the flow, so only a small percentage goes through the sensor). I can also try running a lower inlet pressure, but the main purpose of the exercise is to strip these units and get them working.
I think it is unlikely that these are 'jammed up' with process gunk, as they will only have been connected to a BCL3 supply, and will have had non-return valves fitted downstream.
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Jerry Biehler
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Re: Re-building MKS mass flow controllers
You usually have a +/- 10% range on things like this. In general with sensor you need to be within a volt. Supplies with +/-15v and 5 are pretty common.
Lowering the pressure wont matter. These, with their controller, regulate flow independent of pressure.
Lowering the pressure wont matter. These, with their controller, regulate flow independent of pressure.