eBay compressor

[rws_53]

I think I remember seeing that you could order them set to shut off at your desired pressure.

When I purchased mine two months ago I originally ordered the 220 model because the add stated that it had an Auto shutoff so I emailed the supplier to explain how it was adjusted. I was told that it was an AUTO shutoff when it reached 4500 PSI but was not adjustable for different set points so I ordered the 110 volt model which has neither. It's so fast that I don't mind babysitting it.  Bob

mouse over each small icon next to the Voltage choices at the following link

there are 4 models each in 110v and 220v and priced accordingly
Automatic...shuts off at 4500 psi
Set Pressure...shuts off at the pressure you select
Hardcover...must be shut off manually
Simple...must be shut off manually and there is no cyclone filter (water/oil separator) which is on the other models.

https://www.aliexpress.com/store/product/300BAR-30MPA-4500PSI-High-Pressure-Air-Pump-Electric-Air-Compressor-for-Pneumatic-Airgun-Scuba-Rifle-PCP/2940062_32815880523.html?spm=2114.12010608.0.0.2995e5c0Bg0QUi

[Richard Lee]

The "Hardback Edition" has that extra water trap/bleeder, which I think is nice to have.
But, the extra 'control' hardware that needs to interface with the HPA just seems like more things to go wrong.

If I had to take a phone call while doing a fill, I would just shut it down (bleeding out any water) and come back later.
But, that's just me, and I only need about 15 seconds to top off my PRod.. Maybe around 60 seconds for a rifle..?.

You guys filling up scuba tanks might not want to watch the gauges. (My scuba tanks are all over-due or obsolete).. 
 

[toku58]

The "Hardback Edition" has that extra water trap/bleeder, which I think is nice to have.
But, the extra 'control' hardware that needs to interface with the HPA just seems like more things to go wrong.

If I had to take a phone call while doing a fill, I would just shut it down (bleeding out any water) and come back later.
But, that's just me, and I only need about 15 seconds to top off my PRod.. Maybe around 60 seconds for a rifle..?.

You guys filling up scuba tanks might not want to watch the gauges. (My scuba tanks are all over-due or obsolete).. 
 

A pressure switch is actually really simple in design. All it is, is a simple contactor that gets pushed open when the pressure is high enough.
 It's basically the same principle as the pressure gauge. So it does have a remote chance of malfunctioning. But so does the pressure gauge. The odds of it failing is about the same as the gauge failing.

[Richard Lee]

The "Hardback Edition" has that extra water trap/bleeder, which I think is nice to have.
But, the extra 'control' hardware that needs to interface with the HPA just seems like more things to go wrong.

If I had to take a phone call while doing a fill, I would just shut it down (bleeding out any water) and come back later.
But, that's just me, and I only need about 15 seconds to top off my PRod.. Maybe around 60 seconds for a rifle..?.

You guys filling up scuba tanks might not want to watch the gauges. (My scuba tanks are all over-due or obsolete).. 
 

A pressure switch is actually really simple in design. All it is, is a simple contactor that gets pushed open when the pressure is high enough.
 It's basically the same principle as the pressure gauge. So it does have a remote chance of malfunctioning. But so does the pressure gauge. The odds of it failing is about the same as the gauge failing.

Anyone who fills airguns knows to watch the gauge on the rifle, to make sure it matches the supply gauge.
The pressure gauges I've used over the years were pretty accurate. Those that got hammered too hard, too many times,
didn't become inaccurate, they visibly died with clear indications of failure. Like a broken indicator needle or bent needle,
stuck at 1200 psi etc. The only meters I've had to replace on air guns, were cheap (paintball style) meters that leaked.

It seems like the design of a pressure sensor electrical switch would have to be more than a simple piston pushing a coil spring, until it opened the circuit.
The first worry, is the piston might have leakage, that would allow moist air to flow into the innards.

If the switch opened slowly as pressure built, the contacts might arc and weld the parts into a short.
If the switch plused open during the piston pressure stroke, and closed a few times, that could cause a welding action.
(These 120vac compressors use pretty high current).
So, unless it was a low voltage switch, isolated from high current by a logic controlled SSR,
the switch arm would need some kind of mechanical arrangement to make it Snap open quickly.
Like the clean hysteresis switching of a thermostat..   

We need to face the facts. Using these Chinese compressors might be very risky.
(Us first adopters are the crash test dummies). 
Adding extra risk (by dependence on automatic operation) might not be wise.

I like to drive using cruise-control. Millions of people have logged millions of miles with cruise-control
and now we have a pretty safe 'automatic' device.. But, I'm not ready for the self-driving car..      
 

[toku58]

The "Hardback Edition" has that extra water trap/bleeder, which I think is nice to have.
But, the extra 'control' hardware that needs to interface with the HPA just seems like more things to go wrong.

If I had to take a phone call while doing a fill, I would just shut it down (bleeding out any water) and come back later.
But, that's just me, and I only need about 15 seconds to top off my PRod.. Maybe around 60 seconds for a rifle..?.

You guys filling up scuba tanks might not want to watch the gauges. (My scuba tanks are all over-due or obsolete).. 
 

A pressure switch is actually really simple in design. All it is, is a simple contactor that gets pushed open when the pressure is high enough.
 It's basically the same principle as the pressure gauge. So it does have a remote chance of malfunctioning. But so does the pressure gauge. The odds of it failing is about the same as the gauge failing.

Anyone who fills airguns knows to watch the gauge on the rifle, to make sure it matches the supply gauge.
The pressure gauges I've used over the years were pretty accurate. Those that got hammered too hard, too many times,
didn't become inaccurate, they visibly died with clear indications of failure. Like a broken indicator needle or bent needle,
stuck at 1200 psi etc. The only meters I've had to replace on air guns, were cheap (paintball style) meters that leaked.

It seems like the design of a pressure sensor electrical switch would have to be more than a simple piston pushing a coil spring, until it opened the circuit.
The first worry, is the piston might have leakage, that would allow moist air to flow into the innards.

If the switch opened slowly as pressure built, the contacts might arc and weld the parts into a short.
If the switch plused open during the piston pressure stroke, and closed a few times, that could cause a welding action.
(These 120vac compressors use pretty high current).
So, unless it was a low voltage switch, isolated from high current by a logic controlled SSR,
the switch arm would need some kind of mechanical arrangement to make it Snap open quickly.
Like the clean hysteresis switching of a thermostat..   

We need to face the facts. Using these Chinese compressors might be very risky.
(Us first adopters are the crash test dummies). 
Adding extra risk (by dependence on automatic operation) might not be wise.

I like to drive using cruise-control. Millions of people have logged millions of miles with cruise-control
and now we have a pretty safe 'automatic' device.. But, I'm not ready for the self-driving car..    

Eh? To each his own?!
I'm not here to convince you otherwise.
Just saying that it's not as scary as you might think.
Think of it a ABS on your car.
You still need to watch it but it's an added safety feature, incase you get distracted. Not a "set it and forget it" sort of thing.

[lennyk]

ebay prices appear to be coming down,
lot of units with the cyclone separator but not the adjustable shutoff pressure
at $300 now incl shipping
previously were around $350

[gendoc]

ebay prices appear to be coming down,
lot of units with the cyclone separator but not the adjustable shutoff pressure
at $300 now incl shipping
previously were around $350

what is this "cyclone separator" ?? is this something new we dont have ??

[lennyk]

check 5th pic in the item description on left side

https://www.aliexpress.com/store/product/300BAR-30MPA-4500PSI-High-Pressure-Air-Pump-Electric-Air-Compressor-for-Pneumatic-Airgun-Scuba-Rifle-PCP/2940062_32815880523.html?spm=2114.12010608.0.0.2995e5c0Bg0QUi

it is the bleed thing on the left side if looking at it facing the oil fill gauge
that seller actually has pics of all the versions

[redtrucker610]

Looking on aliexpress the other day came across this separator. This one is a different variation of the large gold filter. It has two extra ports with one having a bleeder valve.

https://www.aliexpress.com/item-img/PCP-oil-water-separator-30-mpa-4500psi-310bar/32815274871.html?spm=2114.10010108.1000017.2.4b24ae2bSX6loe#

[rws_53]

ebay prices appear to be coming down,
lot of units with the cyclone separator but not the adjustable shutoff pressure
at $300 now incl shipping
previously were around $350

what is this "cyclone separator" ?? is this something new we dont have ??

all the Yong Heng models have it except the Simple model...cyclonic action separates oil and water from the air

cut-a-way view



drain it by opening the black knob bleeder

Uploaded at Snapagogo.com

[squirrel_hunter]

 the units are well made and IT DOES NOT SCARE me to use it at all.i fill rifle up directly.unit runs for under 60 seconds when filling rifle.it really does get hot at all.the water cooling is a plus.i cant shoot enough now I don't have to pump and need more ammo...don't be scared to buy and use this unit...respect it and follow directions and you will have a compressor that will pump up your rifles for many fills.

[gendoc]

ebay prices appear to be coming down,
lot of units with the cyclone separator but not the adjustable shutoff pressure
at $300 now incl shipping
previously were around $350

what is this "cyclone separator" ?? is this something new we dont have ??

all the Yong Heng models have it except the Simple model

cut-a-way view

Uploaded at Snapagogo.com

thanks guys !  i thought they done snuck something new in on me.......

[Richard Lee]

That "cyclone separator" has some open space on it's face. About 23mm wide x 57mm tall.

I wonder if you attached a peltier cooler unit to that area, and cooled (30F?) down the whole cyclone separator body,
to lower the dew-point inside. Would that increase the effectiveness of the moisture trap? 
https://en.wikipedia.org/wiki/Thermoelectric_cooling
 
Would it trap enough extra water to make it worth the cost??  Any engineers here?

[rws_53]

Inside look of the Yong Heng "cyclone filter."  Spinning air passing through the filter housing is supposed to fling off oil and water and collect in the cavity below which then is drained off by opening the bleed screw.

cut-a-way view

[MJP]

Golden filter, xiamen SUBANG technology, makes me wonder on the material.... I would not want one go subang on me.
Someone hydro the darn thing just to be safe.

Interesting design on the water separator, that could actually work.
Peltier idea is neat, but you should calculate how much energy there is to be transferred, and you'll need pretty good heatsink or a waterblock for it. 50-80W peltier would be the smallest that I would even reconsider.

Marko

[shultz]

Rws_53,

Thanks for the pics!

I had no idea the low side separator had a sintered filter.... something that should probably be cleaned now and then.

Marko,

That's on the low side, pressure shouldn't be a concern, should it? I'm honestly not sure what the low pressure side pressure is....

Of course, the high side is probably the same set up....that would be a concern.

[MJP]

John, I was referring to the golden filter, it sees the full 300bar pressure. It should be hydro tested to a minimum of 450bar and desing should withstand 3 times the working pressure without rupture. Thats ~900bar.
Makes me wonder does it actually hold that?

Marko

[shultz]

John, I was referring to the golden filter, it sees the full 300bar pressure. It should be hydro tested to a minimum of 450bar and desing should withstand 3 times the working pressure without rupture. Thats ~900bar.
Makes me wonder does it actually hold that?

Marko

Got ya, I thought you were talking about the gold color sintered filter in rws_53 picture.

Yeah, I wonder about my gold high side filter... but, it was "hydrostatic test 50MPA completely" Does one really need more reassurance?

I'm rolling the dice for sure. I don't even know of anyone that could hydro test it, or, I would have had it done just for piece of mind. I will say, it appears to be thick enough and has plenty of threads at the end caps to hold the PSI were dealing with, assuming the material its constructed from is OK....

[shultz]

Gentleman,

check your cyclone separator!

Mine was not cycloning... the cyclone sleeve had unthreaded itself(assuming it was threaded on to begin with) and just laying at the bottom of the separator housing...

Sleeve is back on the body and tight, might actually work better now...

[gendoc]

is the oring 1 of the spares that came with the compressor ?
before i remove it, i'd like to have one on hand...just incase