Why aren't these compressors popular ?

[toocoolforschool]

They are not popular because they only last a couple of mths.

[motoguy128]

Wow, I never knew they made those for refrigeration use. There's a company that makes low psi air compressors that work the same way and their reliability is light years ahead of the conventional piston compressors. A store I work for has had them on the air supplies for lobster tanks for 15 years now with no maintenance or failures. All the other stores are using more expensive conventional piston compressors that need to be replaced every 5 years and use almost 5 times more power.


Seems like a no brainer for refrigeration use.

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

Really, from that standpoint, the design is short sighted. It might as well have 2 cylinders, one at each end and just use a reed valve or similar as a check valve.

[motoguy128]

Someone just told me that Engel has a patent on the compressor design and doesn't want to allow anyone else to make them. I guess that would explain why they aren't in common use. I wonder what triggers the power on and off the the wound coil?

Probably SCR's (I think that's the term) some sort of solid state device similar to what's in an inverter. More similar I suppose to a Servo drive since it's a PM magnet for the stator. As stated in the mfg website, the stroke lenght and speed are vairable which allows low start-up load and I suppsoe also vairable compression ratio.

[craig1]

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

The ones they had in these lobster tanks were huge compared to your standard aquarium pump. 3/4" air outlet and capable of about 30 PSI. When I looked them up on the Internet they showed how it worked and it was a Teflon coated floating piston the slid back and forth in a tube. Very cool design. Apparently most of these style pumps are used as septic tank aerators.

[motoguy128]

Small enough to be powered by a 12VDC or 24VDC power source... Can't even venture a guess, but suspect it's under 2000 BTU's

GT

At 12VDC< 100 Amps it's unreasonable for a constant load, with a peak load under 200 Amps with size 0 cables. So that's puts you at 1200Watts, or with a COP or 3, that's as much as 12,000 BTU's. BUt I think you'll be limited there. I think the small AC units that companies like Webasto make for sleeps babs are in the range of 6000-12000 BTU's.

[Poodle Head Mikey]

The company claims that they last for decades - with some still running since the 1960's.

Where did you get the information that they only last a few months?

PHM
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They are not popular because they only last a couple of mths.

[icemeister]

After a little digging, I found that this swing motor compressor has been made by Sawafuji in Japan, who purchased the licensing from its West German inventor in 1956. Apparently, Engel wasn't the only ones using it because Sawafuji also made mobile mini-fridges with the swing motor compressor and sold them in the USA under the name of Norcold.

They use an inverter to control the oscillating frequency to match that of the spring resonance in the motor.

[craig1]

I wonder what triggers the power on and off the the wound coil?

If you're powering it from a standard AC power source you don't need any type of controller, it will run at 60 cycles per second, just like the AC frequency.

[Poodle Head Mikey]

Why don't solenoid valves do that then? Aren't they pretty much the same thing except out in the open?

Wait a minute: say the piston stroke was just 1" long. That would have the piston covering over 430,000 inches every hour. Which is over 80 MPH. <g>

Are you sure that's the operating speed on 60 cycle power supply?

PHM
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coils

If you're powering it from a standard AC power source you don't need any type of controller, it will run at 60 cycles per second, just like the AC frequency.

[Poodle Head Mikey]

Nope! I'm wrong - it's not even 7 mph. I forgot the 12 to get down to feets.

Sorry about that. <g>

[toocoolforschool]

The company claims that they last for decades - with some still running since the 1960's.

Where did you get the information that they only last a few months?

PHM
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Bought the norcold . POS.

[engineerdave]

I thought this looked cool, haven't seen one in real life yet...
www.turbocor.com

[motoguy128]

They sound expensive.