BL-520 Fuel metering device

[rikukiakuchiki777]

Is anyone able to explain how the metering device found on the BL-520 works? (http://ultimatespudgun.com/product_info ... cts_id=178) There is a brief explanation located at the above link, however it is quite vague. Any diagrams would be nice, they make everything so much easier . I am curious about the one-way safety valve they talk about; "when the action is pushed forward the metered gas is injected into the chamber of your spudgun through a one way safety valve". How does this work? does the pressure of the gas fuel allow the safety valve to open, releasing the fuel into the chamber?

[inonickname]

There are two check valves I believe- propane or mapp flows through a check valve on the upstroke of the pump, allowing pressure to equalize between bottle and pump. When the pump is pushed down high pressure causes that valve to close.

Then I'm unsure on how it's delivered to the chamber- a higher pressure check valve, or a valve that is depressed by the pump stroke.

[Technician1002]

There are two check valves I believe- propane or mapp flows through a check valve on the upstroke of the pump, allowing pressure to equalize between bottle and pump. When the pump is pushed down high pressure causes that valve to close.

Then I'm unsure on how it's delivered to the chamber- a higher pressure check valve, or a valve that is depressed by the pump stroke.

I have my doubts it's a pump even though it looks like one. Watch him operate it. It uses a short stroke. I'm thinking it's a spool valve with metering chamber in the middle. The safety is just a check valve in my opinion so the chamber pressure surge doesn't launch the valve core.

I'm pretty sure by the video that this is simply a custom version of the standard metering tube and 2 ball valve system, but using a spool valve setup on a common rod.

Edit Added quick cheezy paint sketch. O ring seals not shown. One push vents the space to the chamber through a check valve not shown and the other way seals off the chamber and opens the meter to the propane pressure. This is how I think it works.

Edit Checked the specs on the meter. It is a metered volume regulated by pressure just like any regulated metering volume / valve setup.

[inonickname]

I hadn't though of that, though in thinking about it you are completely correct. The balanced nature of it also explains there being no noticeable resistance.

[jagerbond]

Technician1002 is correct, simple and effective. The one-way keeps pressure/combustion from back tracking and keeps the pipeline mixture consistent for repeated precise meterings. The diagram was an early mock up.

Mike
Sureshot Inc. / http://www.ultimatespudgun.com

[rikukiakuchiki777]

Whoa, that is so much simpler than I expected, and i can't believe i even got a response the same day as posting. Thanks so much guys!

[FeLeX]

How does this work without having a pressure guage??

[CS]

Pressure gauge and a regulator. *spoonfeed*