Some of the gyroscopes I've got require vacuum to spin and so the search for a suitable vacuum pump. There is a way to generate vacuum from compressed air, but it makes a lot of noise so I haven't used that method.
While working on cars I learned that there's a difference in tubing designed for pressure and vacuum. This shows up in the cooling water system where a failure mode is the collapse of the lower (pump input or vacuum side) radiator hose. This can happen if the wrong type of hose is used. What's needed is a lower hose with a metal coil spring inside to keep it from collapsing. There can be a similar problem with fuel hose on the input side of the fuel pump.
In a similar manner thin wall tubing will have a tendency to collapse when used for vacuum, but will be OK when used for pressure.
The tubing that came with the small 50~90Kpa Pressure Vacuum pump air water pump is only good for pressure, it flattens when used for vacuum.
I suspect that the vacuum level and volume are directly related to the electrical power consumed by the motor (and that may be related to the volume of the motor).
So far all of these small vacuum pumps have DC motors which means that by reversing the polarity of the motor input power you can change from vacuum to pressure on a port.
Placing a sheet of paper over a port allows telling if that port is pressure output or vacuum (the paper sticks to a vacuum port).
p/n: ROB-10398 about $15 ($5.50 @50 ea Alibaba
36mm dia x 58mm long
3.12mm (1/8") shaft dia
Airpo Model D2028B, 12 VDC
Current (12.0 VDC no load):
No Load: 0.49 A
blocked vacuum: 0.62 A
blocked pressure: 1.0 A (12 Watts)
6mm narrow nipple dia: 1/4" tubing
DC 12V small diaphragm pump -50~90Kpa Pressure Vacuum pump air water pump 1L/min
eBay seller: chenswg95 about $15 includes some 8mm tubing
This pump has a much lower capacity than the SparkFun pump above.
Pump & pressure tubing (not vacuum tubing)
Current (12.0 VDC no load):
No Load: 0.06 A
blocked vacuum: 0.07 A
blocked pressure: 0.08 A (1 Watt)
24mm x 31mm long
marked: RF-370CA-08V16, EA3 12 21 001
marked: Liquid Pump, CJWP40-B09D1, DC 9V OJ123DC, PT(TW.CN...) CONJOIN
mounting holes 2 ea, 3.5mm ID14mm c-c
7.9mm narrow nipple dia: 8mm tubing
Gomco M180 Suction machine/Aspirator aka OptiVac
This is hospital equipment and includes an internal battery. Got it on eBay with low offer, maybe because the internal batteries are in poor condition, remains to be seen.
On the left are the On button, Off button, and 5 Battery status LEDs.
On the right is the vacuum gauge (0 to 30" Hg, 0-700+ mm Hg) and the pressure regulator knob.
The hose bib at the top has a min dia of 8mm so may work with the 8mm tubing for the above CJWP40 pump.
12 - 16 VDC @ 3.4 A (41 - 54 Watts)
Leaving the unit plugged in (charging the lead acid battery) overnight. This model should run for 180 min (3 hours) on battery power. I suspect much less, i.e. dead battery.YouTube - Unboxing and In-service of the G180 OptiVac Emergency Portable Aspirator
It's not clear how to use an external 12 Volt battery.
Works when plugged-in.
Back: IEC line socket & battery fuse
After overnight plugged-in charging 5 LEDs are on
Unplugged and then press "Off" to check charge status
5 minutes or less of run time i.e. battery is dead
Pressing On does nothing when unplugged,
the battery is completely dead.
Rear cover hinged down showing foam air filter
pump on left, battery on right
There are 3 loose combined nut-lockwashers &
3 flat washers clinging to the motor by magnetism.
It is not obvious where they came from.
Gast model: 22D118-225-1088
Diaphram pump & motor
Power Supply similar to Meanwell (Jameco: PS-65-15)
Counterweight, black plastic connecting rod
Inlet at top
Power supply PCB on right
Main board behind panel
There are 7 LEDs (only 6 on panel)
Provision for optional 3rd push button
Practical Wiring diagram © Brooke Clarke 2015
What are the 3 unconnected wires (Gry, Org & Vio) for?
let me know
New Powersonic PS-1250 Battery
Battery as received shows 3 Green LEDs out of 5
With AC power all 5 LED Battery Status LEDs are on
Vacuum is 550 mm Hg.
Note tubing is not vacuum rated and has flattened.
2000 cccanister with central float, shown down.
When canister fills up the float turns off the vacuum.
The 3 nuts are for holding the canister holder.
Automotive 3/8" gas line with hose clamp on pump.
Gauge showing 600 mm Hg on battery power (4 green LEDs)
From the owner's manual.
3.6 When the unit is on, is being charged, or testing battery status (pushing “off” button), the LED’s indicate the
state of the battery as follows:
- Five green LED’s indicate a fully charged battery condition.
- Four/three green LED’s indicate a normal battery condition, but not fully charged.
- Two red LED’s indicate a drained battery condition with limited run time.
- One red LED indicates a drained battery condition, unit will shut down soon. (my case)
- Five red LED’s, during charging only, indicate the battery needs to be replaced.
* The battery should be recharged every two weeks even if it hasn’t been used. To store the aspirator for periods of time longer than one month, the battery connection fuse (sec. 2.3) should be removed.
For optimum battery performance the unit may be left plugged in at all times. The unit will turn the charging circuit “On & Off” to keep the battery at a full charge level.
eBay title: Power-Sonic WKA12-5F 12 volt 5 ah battery is the same as Power-Sonic PS-1250 F1. about $16.(ordered 29 Oct 2015)
I've reassembled the unit and it works fine without a battery. Will install the battery when it arrives.
Still don't know where the 3 nuts & washers came from??
872795 Double-walled vessel with a space for a vacuum between the walls, Reinhold Burger, American Thermos Bottle Co, 1907-12-03, 215/12.2; 65/153 - typically achieved using a glass bottle, which can easily break.
1071817 Heat-insulated receptacle, William Stanley, Sep 2,1913, 220/592.16; 126/261; 215/13.1 - points out problems of maintaining hard vacuum in steel container and fix by adding filler.
Glass to metal seals and testing for leaks - Modules - H2 vs He
Pendulums - then [CTRL]+F Vacuum
Thermal Vacuum - to simulate very high altitudes or outer space is very difficult to achieve - photo
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Page created 26 Oct 2015