Haskel pneumatic refrigerant pumps

[FatherEarth]

deep vacuum only once per run

deep vacuum only once per run

Temperature, surface area and volume being the variable determining factors. Im curious as to how much butane is still in the recovery pot at 0 psi in a 12' recovery pot half full @ 35F...Since the industry standard technique is to pour off, Im wondering how much of a problem having no vac is? I quit pulling deep vacuum during finish and recovery when temps are 20f or above. Im able to preserve terpenes this way, as long periods of deep vacuum there is a noticeable difference in the terpene profile. The initial deep vac to get the air out of the system is the only time I will go to -29. Adding sub zero temperature pre vacuum sealed columns to the system is the way to go. Im tired of not having the proper equipment to recover safely and the EXT420 is made of the right materials and is safe. Im still leaning towards the EXT420 despite its lack of - vac capabilities. Still surprising your meetings with industry leaders pulling a vacuum didnt arise as a topic...
Should have been doing R&D meetings here..heh


Respectfully,

FE

 

[cyphaman]

Regarding the questions about pulling vacuum, while I know that my research is not complete, I have met with OEM's in Washington, Oregon, California and Colorado (some are very big names in the industry). In all of my meetings, pulling vacuum was never discussed, I was told by most everyone that suction pressures would be about 50 psig, pumping up to about 150 psig. That is why the EXT420 is configured the way it was (this is also detailed in some of the very early postings on this thread).

As I have also described, the EXT420 is similar, but not the same as the 59025-3. Both have PTFE and viton seal packages. However, the EXT420 displaces 19.6 cubic inches per stroke, while the 59025 will only displace 10 cubic inches per stroke. The difference is because the 59025 is a two-stage unit, which means that the gas gets pumped twice while it's in the pump, this allows the 59025 to pull vacuum. The EXT420 is a single-stage unit, which means the gas is only pumped once while it's in the pump, but this makes it very inefficient with low inlet pressures. Additionally, the EXT420 has all stainless steel connection fittings (the 59025 uses plated steel) and the EXT420 also has all the vent ports captured to make it easy to vent any leaked gas (should be very minimal) to a safe location.

I have been told by a couple of OEM's that reconfigured the 59025 to a single-stage unit (basically an EXT420 prototype) that it cut their transfer times almost in half compared to the 59025-3.

Thanks for the questions, keep them coming!

I believe hes referring to Xtracted here..they mentioned that Haskel worked with them to modify all theirs. sweet

 

[Dave at Haskel]

I had a discussion with Haskel Engineering about how much vacuum an EXT420 can pull and I'll explain what I was told.

I am going to get a little technical, but I'll try to keep the information as simple as possible. The EXT420 has a maximum gas compression ratio of about 10:1. The boost ratio is calculated by dividing the desired output pressure by the incoming pressure. For example, if I wanted to bring the gas to 150psig and I had an inlet pressure of 50 psig, the gas compression ratio would be 3:1 (150psig/50psig = 3). These calculations work fine when we are working well above 0 psig, however, the math doesn’t work when working in pressures around or below 0 psig.

The easiest solution is to convert to absolute pressures. If you aren’t familiar with absolute pressures (indicated by psia), absolute pressure start at absolute 0 pressure and what we normally think of as 0 psig is actually 14.7 psia. If you were pulling a vacuum in a vessel of 10” Hg, that would be approximately -5 psig or 10 psia. Or, a full vacuum of 29.92” Hg would be the same as 0 psia.

To convert psig to psia, all you do is add 1 atmosphere (14.7 psia) of pressure to the psig values. When you do this in the above example, the output pressure of 150 psig = 164.7 psia and 50 psig = 64.7 psia. Using psia, the compression ratio does change to 2.6:1.

In extraction, if you are pulling a vacuum to 20” Hg, that pressure equates to approximately -10 psig or 5 psia. We can then calculate the maximum output pressure with an inlet of 5 psia by multiplying it by the maximum compression ratio of 10. That is, 5 psia * 10 = a maximum output pressure of 50 psia, which is about 35 psig. You maybe able to get a higher outlet pressure, but as the gas compression ratio goes up, the flow will go down.

I hope that information helps. Let me know if you have questions.

Dave

 

[gholladay]

I had a discussion with Haskel Engineering about how much vacuum an EXT420 can pull and I'll explain what I was told.

I am going to get a little technical, but I'll try to keep the information as simple as possible. The EXT420 has a maximum gas compression ratio of about 10:1. The boost ratio is calculated by dividing the desired output pressure by the incoming pressure. For example, if I wanted to bring the gas to 150psig and I had an inlet pressure of 50 psig, the gas compression ratio would be 3:1 (150psig/50psig = 3). These calculations work fine when we are working well above 0 psig, however, the math doesn’t work when working in pressures around or below 0 psig.

The easiest solution is to convert to absolute pressures. If you aren’t familiar with absolute pressures (indicated by psia), absolute pressure start at absolute 0 pressure and what we normally think of as 0 psig is actually 14.7 psia. If you were pulling a vacuum in a vessel of 10” Hg, that would be approximately -5 psig or 10 psia. Or, a full vacuum of 29.92” Hg would be the same as 0 psia.

To convert psig to psia, all you do is add 1 atmosphere (14.7 psia) of pressure to the psig values. When you do this in the above example, the output pressure of 150 psig = 164.7 psia and 50 psig = 64.7 psia. Using psia, the compression ratio does change to 2.6:1.

In extraction, if you are pulling a vacuum to 20” Hg, that pressure equates to approximately -10 psig or 5 psia. We can then calculate the maximum output pressure with an inlet of 5 psia by multiplying it by the maximum compression ratio of 10. That is, 5 psia * 10 = a maximum output pressure of 50 psia, which is about 35 psig. You maybe able to get a higher outlet pressure, but as the gas compression ratio goes up, the flow will go down.

I hope that information helps. Let me know if you have questions.

Dave

Great explanation Dave thank you. Can anyone comment on how this outlet pressure compares to that of an RG6000 for a sense of reference?

 

[Gray Wolf]

Great explanation Dave thank you. Can anyone comment on how this outlet pressure compares to that of an RG6000 for a sense of reference?

The RG6000 has a 550 psi high pressure upper limit turn off switch.

At 4:1, the Haskel would require about ~138# of air pressure, which is within its pressure rating.

There is no need to operate anywhere near those pressures, so that is a non issue.

 

[Gray Wolf]

I had a discussion with Haskel Engineering about how much vacuum an EXT420 can pull and I'll explain what I was told.

I am going to get a little technical, but I'll try to keep the information as simple as possible. The EXT420 has a maximum gas compression ratio of about 10:1. The boost ratio is calculated by dividing the desired output pressure by the incoming pressure. For example, if I wanted to bring the gas to 150psig and I had an inlet pressure of 50 psig, the gas compression ratio would be 3:1 (150psig/50psig = 3). These calculations work fine when we are working well above 0 psig, however, the math doesn’t work when working in pressures around or below 0 psig.

The easiest solution is to convert to absolute pressures. If you aren’t familiar with absolute pressures (indicated by psia), absolute pressure start at absolute 0 pressure and what we normally think of as 0 psig is actually 14.7 psia. If you were pulling a vacuum in a vessel of 10” Hg, that would be approximately -5 psig or 10 psia. Or, a full vacuum of 29.92” Hg would be the same as 0 psia.

To convert psig to psia, all you do is add 1 atmosphere (14.7 psia) of pressure to the psig values. When you do this in the above example, the output pressure of 150 psig = 164.7 psia and 50 psig = 64.7 psia. Using psia, the compression ratio does change to 2.6:1.

In extraction, if you are pulling a vacuum to 20” Hg, that pressure equates to approximately -10 psig or 5 psia. We can then calculate the maximum output pressure with an inlet of 5 psia by multiplying it by the maximum compression ratio of 10. That is, 5 psia * 10 = a maximum output pressure of 50 psia, which is about 35 psig. You maybe able to get a higher outlet pressure, but as the gas compression ratio goes up, the flow will go down.

I hope that information helps. Let me know if you have questions.

Dave

Thanks Dave!

It does change things when the molecules get fewer and further apart, doesn't it??

As you note, having enough pump stroke to compress the molecules present ten times, doesn't give you the same pressure when only half as many molecules are present and if you are pulling vacuum on one side, you are more limited in out put pressure.

Here is a propane/butane mix versus temperature and pressure chart, which shows what will be needed in after pump and tank chilling to operate at 35 psig.

http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

 

[gholladay]

GW, thanks for the answer, but let me rephrase the question. When I operate my MKiii with the RG6000, my tank pressure is typically around 80 psig. Looking at the gauge on the RG6000 while it's running shows the pressure on the backside to be in the 80-90 psig range.

If the haskel will only push ~ 35 psig when recovering from a full vacuum, is that enough pressure to push the butane into the tank? or will we have to cool the tank down considerably to make it work (according to your chart, 0 °F)?

If I'm on the wrong track here, someone please correct me. Would it be correct to say that this pump is geared more toward speed than achieving higher backside pressures?

Thanks,
G

 

[Gray Wolf]

GW, thanks for the answer, but let me rephrase the question. When I operate my MKiii with the RG6000, my tank pressure is typically around 80 psig. Looking at the gauge on the RG6000 while it's running shows the pressure on the backside to be in the 80-90 psig range.

If the haskel will only push ~ 35 psig when recovering from a full vacuum, is that enough pressure to push the butane into the tank? or will we have to cool the tank down considerably to make it work (according to your chart, 0 °F)?

If I'm on the wrong track here, someone please correct me. Would it be correct to say that this pump is geared more toward speed than achieving higher backside pressures?

Thanks,
G

It has no problem putting out 150 psi X 4:1 or 600 psi, but it can't pull a vacuum and put out 600 psi at the same time, because the compression ratios changes as the amount of butane left diminishes.

It is fair to say that running it in single stage mode, will require that you cool the mixture before returning to the tank, to keep from having pressures above 35 psi while pulling a -20" Hg vacuum.

If that doesn't appeal to you, consider plumbing it so that you can run it in either single for speed or two stage mode for finishing.

 

[gholladay]

Excellent! That's what I thought. And I do see that it is capable of reaching higher pressures when a higher inlet pressure is used. So most of the time during recovery you'd be able to achieve the back pressures needed to push tane into the tank. It would only be at the very end of recovery that the back pressure would decrease to a point where you would need a chilled tank to make it work (although chilling the tank and using a cooling coil would speed up the entire process, just like when any other pump is used).

I suppose there is still a need for the cooling coil after this pump due to the temp increase from pressurizing the fluid. For some reason I was under the impression one wouldn't need a cooling coil when using the haskel, but I see now that you would.

I really like the idea of being able to switch between single stage and two stage like you're saying. And I bet a mod like that would be easily achieved with the properly placed valves. Cool idea! Have you tried that before GW?

G

 

[Gray Wolf]

Excellent! That's what I thought. And I do see that it is capable of reaching higher pressures when a higher inlet pressure is used. So most of the time during recovery you'd be able to achieve the back pressures needed to push tane into the tank. It would only be at the very end of recovery that the back pressure would decrease to a point where you would need a chilled tank to make it work (although chilling the tank and using a cooling coil would speed up the entire process, just like when any other pump is used).

I suppose there is still a need for the cooling coil after this pump due to the temp increase from pressurizing the fluid. For some reason I was under the impression one wouldn't need a cooling coil when using the haskel, but I see now that you would.

I really like the idea of being able to switch between single stage and two stage like you're saying. And I bet a mod like that would be easily achieved with the properly placed valves. Cool idea! Have you tried that before GW?

G

You will always have the heat of compression to remove, and the heat of vaporization to return it into a liquid state.

No, I haven't tried to run one both ways, but looks like I get to do so.

WolfWurx just received three more 59025-3 Haskels to install on turnkey machines, and opportunities to experiment.

 

[gholladay]

Sounds good. I just went back and reread some of this thread again for clarification. Right now, from what I've gathered, the EXT420 would need to be modified to alternate between single and two stage operation to be able to recover at a vacuum. Dave states pretty clearly that the EXT420 is only rated to 0 psig in it's standard configuration.

Now with the 59025 model, it will pull a vacuum to -20 hg, but it operates a little slower than the EXT420 would. But in theory, you can make this modification to alternate between single and two stage for the 59025 model as well, which would allow the pump to work faster when encountering higher inlet pressures, and then work slower (but achieve higher back pressure) when the pressure passed below 0 psig.

I'm curious to know if you would still recommend using two 59025 pumps to recover simultaneously, or if one pump, with that staging mod would be sufficient. I guess you would need to consider how much compressed air you had available.. What would your ideal recovery pump system look like if cost wasn't an issue?

Thanks,
G

 

[Dave at Haskel]

Sounds good. I just went back and reread some of this thread again for clarification. Right now, from what I've gathered, the EXT420 would need to be modified to alternate between single and two stage operation to be able to recover at a vacuum. Dave states pretty clearly that the EXT420 is only rated to 0 psig in it's standard configuration.

Now with the 59025 model, it will pull a vacuum to -20 hg, but it operates a little slower than the EXT420 would. But in theory, you can make this modification to alternate between single and two stage for the 59025 model as well, which would allow the pump to work faster when encountering higher inlet pressures, and then work slower (but achieve higher back pressure) when the pressure passed below 0 psig.

I'm curious to know if you would still recommend using two 59025 pumps to recover simultaneously, or if one pump, with that staging mod would be sufficient. I guess you would need to consider how much compressed air you had available.. What would your ideal recovery pump system look like if cost wasn't an issue?

Thanks,
G

Lots of comments and questions. Yes to Gray Wolf, as the pressure goes down, the distance between the gas molecules increases, which means that the pump is moving less gas per stroke, which is why the flow goes down as the inlet pressure goes down.

Since the 59025 is a two-stage pump, it has a maximum compression ratio of 100:1, so in the example earlier with a vacuum of 20" Hg (5 psia) the maximum outlet pressure will be 5 * 100 = 500 psia or 485 psig. As I just mentioned, the flow rate will be low because of the very low inlet pressure.

Regarding the question from Gholladay above, you could use 2 of the 59025 pumps to equal the output of 1 of the EXT420, however, you will also use twice as much compressed air as a single EXT420. As Gray Wolf mentioned, I think modifying the EXT420 (or the 59025-3) with the valve to allow switching between one-stage and two-stage mode is the most efficient and simplest way to do this (using 2 of the 59025's plumbed in parallel could get quite complicated on the plumbing).

Dave

 

[Gray Wolf]

Sounds good. I just went back and reread some of this thread again for clarification. Right now, from what I've gathered, the EXT420 would need to be modified to alternate between single and two stage operation to be able to recover at a vacuum. Dave states pretty clearly that the EXT420 is only rated to 0 psig in it's standard configuration.

Now with the 59025 model, it will pull a vacuum to -20 hg, but it operates a little slower than the EXT420 would. But in theory, you can make this modification to alternate between single and two stage for the 59025 model as well, which would allow the pump to work faster when encountering higher inlet pressures, and then work slower (but achieve higher back pressure) when the pressure passed below 0 psig.

I'm curious to know if you would still recommend using two 59025 pumps to recover simultaneously, or if one pump, with that staging mod would be sufficient. I guess you would need to consider how much compressed air you had available.. What would your ideal recovery pump system look like if cost wasn't an issue?

Thanks,
G

Ummm, it will pull below 0" Hg, but not produce adequate pressure on the discharge side while doing so.

The pumps are identical from a capacities standpoint. Either can be run single or double stage, but the 420 is being delivered as a single stage.

Two pumps would be sweet, and another pump isn't all that much more in a relative sense, but they consume a lot of air.

The incremental cost of a larger compressor is relatively small, not double, but it also increases your electrical installation and operating costs.

You get about 4 scfm per horsepower from a screw compressor, so consider that 40 scfm Haskel a 10 hp pump.

What Dave said! Just as you could switch between two pumps, you can switch between single and double stage, so that at the same 10 hp, you can achieve the low input and high 100:1 output pressure, which is what we are currently planning.

It is interesting to note that while we have been talking about what happens to compression ratios as the inlet pressure drops, but passed by what happens when the inlet pressure increases.

In double stage, the Haskel has a rated output pressure of 1250 psi, so with only a 4:1 differential, that means the input pressure was around 312.5 psi.

Because at the higher pressure, the molecules are crammed closer together, the total volume of gas moved by the pump per unit of time, is higher.

 

[gholladay]

Awesome! Thanks for the answers guys! I think this stuff is so cool!

I really like the idea that HL45 had earlier here, which was to use "a solenoid to switch at or near 0hg activated by a pressure switch Automatically". Now that would be so slick. Basically you would have a alternating single-to-two-stage pump with automatic switch over!

I guess it would make sense to build this mod the manual way first to make sure it works like we expect, and then try to put together an automated valve system like that.

Dave, what aspects of using two of those pumps in parallel would get complicated? I'm assuming that I don't have all the necessary components accounted for in my head. What all would a parallel system like that entail?

GH

 

[Dave at Haskel]

Dave, what aspects of using two of those pumps in parallel would get complicated? I'm assuming that I don't have all the necessary components accounted for in my head. What all would a parallel system like that entail?

GH

Maybe I made it sound worse than it is. It would require a couple of T's, one on the inlet side and one on the outlet side. You would also want to have separate drive air controls for each pump, especially the speed control valves (a globe valve or a needle valve to throttle the drive air flow). Sometimes when you have two pumps running parallel with each other in a circuit you will get some odd interactions between the two units, so to keep that from happening, you need separate control valves.

Hope that helps!

Dave

 

[gholladay]

Thanks Dave. Sounds like it's definitely doable. I like the idea of having separate air control valves anyway, that way you could use the second pump for a different system if desired.

GH

 

[Gray Wolf]

I'm new to the Haskel, but have used pneumatic intensifiers for hydrostatic testing equipment, and hydraulics. I've always installed a separate water trap, coalescing filter, pressure regulator, and throttle for each pump. In those cases, I also installed an inline oiler for the drive piston end.

Sometimes interesting things happens with harmonics.

For instance, if you put pneumatic eccentric vibrators on opposite ends of a conveyor, they will sync all by them selves.

PS: Some of ya'll older members might remember the 1976 bicentennial Freedom Train 4-8-4 Daylighter #4449 locomotive that toured the US.

http://en.wikipedia.org/wiki/Southern_Pacific_4449

I helped restore that gorgeous lady as a volunteer, and supplied the Sprague pneumatic intensifier hydrostatic test pump for her rebuilt boiler, borrowed from a valve testing project I was doing for Dillingham Marine and Manufacturing.

 

[CLOSEDloopin710]

need a rep

need a rep

Dave I'm in Washington and have contacted local reps 5 times. They don't reply. How can I purchase a pump?

 

[Dave at Haskel]

Dave I'm in Washington and have contacted local reps 5 times. They don't reply. How can I purchase a pump?

Send me an email with a phone number, I'd like to discuss this with you.

My email: david.gordon@haskel.com

Thanks,

Dave

 

[Gray Wolf]

I'm confident Dave can resolve your WA issues, and we couldn't be happier with our Oregon HIS rep's response and support.

WolfWurx just received three more from them in 59025-3 configuration. When they are in stock, they've delivered the pumps the following day via UPS.