A Close Encounter: The Explosion of a Valve
Posted: Sat Apr 14, 2007 8:15 pm
It was 53 degrees Fahrenheit at the time, about 8:40 PM. I decided I would shoot my <a href="http://www.spudfiles.com/forums/midsize ... mericannon Mini</a>, as it is my favorite spudgun that I have made. I took a ping-pong ball, injected it with water until it was filled, and loaded it into the cannon. I then setup a target outside, and brought the launcher outside. I attached it to my compressor, and filled it until the gauge read 30 PSI. The gauge on my universal filling system is broken, so it probably was not truly 30 PSI. However, my compressor is regulated down to 50 PSI, so unless that regulator was broken (which I highly doubt it was), the launcher had no more than 50 PSI in it.
I fired the ping-pong ball at the target (and I missed, low by about one foot), and a tremendous BOOM followed. I was surprised by the great noise created for only 30-50 PSI, but this cannon had always been loud, and so I was not worried. I then brought it inside, and placed it down on the carpet. When I went to shut the garage door, I noticed a large white scratch had developed on the side of my newly painted valve. Upon closer inspection, I realized that the valve had developed a large crack on the entire right side of the tee.
<img src="http://www.spudfiles.com/uploader/uploa ... ack333.JPG">
It is difficult to determine how this happened. It couldn't have been the temperature, because it was not that cold. It couldn't have been the pressure, because it was only 30-50 PSI. I believe that I did not have a sufficient bumper. I have an air hose coiled up inside of the metal bushing, but it does not extend past the edge of the bushing. There is one piece of foam rubber on the piston, hardly enough to stop the forces involved here. I think the piston slammed back, and the edge of the piston (a 2.5" piece of 1.875" type II PVC rod wrapped with some duct tape) hit the edge of the metal bushing. The bushing then was forced backward, and it pulled the PVC parts of the piston valve backwards, causing this huge crack to develop. The piston is unharmed (as far as I can tell).
I was holding the launcher by the chamber and the barrel at the time, and the valve was behind me. I am so very lucky that I was not holding any part of the valve, because that might have turned very ugly.
I am completely unhurt; I did not even realize that the launcher had failed until minutes after, when I saw the white crack on the black paint.
Some more pictures:
<a href="http://www.spudfiles.com/uploader/uploa ... PG">Female Adapter</a>
<a href="http://www.spudfiles.com/uploader/uploa ... 3.JPG">Top of the Valve</a>
<a href="http://www.spudfiles.com/uploader/uploa ... >Piston</a>
<a href="http://www.spudfiles.com/uploader/uploa ... PG">Inside the Valve</a>
While this might not have been a complete explosion that shattered the valve, the crack which runs through the valve shows that an incredible amount of force was present which caused the valve to break.
If anyone else has any insight on why this might have happened, I would appreciate it. I am just so thankful I came away with this with no injuries.
I fired the ping-pong ball at the target (and I missed, low by about one foot), and a tremendous BOOM followed. I was surprised by the great noise created for only 30-50 PSI, but this cannon had always been loud, and so I was not worried. I then brought it inside, and placed it down on the carpet. When I went to shut the garage door, I noticed a large white scratch had developed on the side of my newly painted valve. Upon closer inspection, I realized that the valve had developed a large crack on the entire right side of the tee.
<img src="http://www.spudfiles.com/uploader/uploa ... ack333.JPG">
It is difficult to determine how this happened. It couldn't have been the temperature, because it was not that cold. It couldn't have been the pressure, because it was only 30-50 PSI. I believe that I did not have a sufficient bumper. I have an air hose coiled up inside of the metal bushing, but it does not extend past the edge of the bushing. There is one piece of foam rubber on the piston, hardly enough to stop the forces involved here. I think the piston slammed back, and the edge of the piston (a 2.5" piece of 1.875" type II PVC rod wrapped with some duct tape) hit the edge of the metal bushing. The bushing then was forced backward, and it pulled the PVC parts of the piston valve backwards, causing this huge crack to develop. The piston is unharmed (as far as I can tell).
I was holding the launcher by the chamber and the barrel at the time, and the valve was behind me. I am so very lucky that I was not holding any part of the valve, because that might have turned very ugly.
I am completely unhurt; I did not even realize that the launcher had failed until minutes after, when I saw the white crack on the black paint.
Some more pictures:
<a href="http://www.spudfiles.com/uploader/uploa ... PG">Female Adapter</a>
<a href="http://www.spudfiles.com/uploader/uploa ... 3.JPG">Top of the Valve</a>
<a href="http://www.spudfiles.com/uploader/uploa ... >Piston</a>
<a href="http://www.spudfiles.com/uploader/uploa ... PG">Inside the Valve</a>
While this might not have been a complete explosion that shattered the valve, the crack which runs through the valve shows that an incredible amount of force was present which caused the valve to break.
If anyone else has any insight on why this might have happened, I would appreciate it. I am just so thankful I came away with this with no injuries.