Post by SeaRat on Mar 18, 2016 19:16:17 GMT -8
Actually, this is an upstream pilot valve, as described in the first paragraph of the patent. But, it does incorporate overprescribing sure protection:
'Sorry, I just learned how to use size and the color to emphasize a point.
John
What is claimed and desired to be secured by Letters Patent is:
...5. In a breathing apparatus for supplying fluid under pressure to a user on demand and at ambient pressure, the breathing apparatus including a casing having an inlet for fluid under pressure, and an outlet for a user: a pilot valve and main valve assembly within said casing and connected to the inlet comprising a control chamber within said assembly, a main diaphragm valve subassembly segregating said control chamber from the breathing apparatus inlet, a pilot valve subassembly located within said control chamber at an end thereof opposite said diaphragm valve and means communicating fluid from said inlet to said control chamber whereby, in response to user demand, said pilot valve is opened to reduce pressure within said control chamber to open said main diaphragm valve and, upon termination of user demand, said pilot valve closes, pressure in said control chamber equalizes with inlet pressure through said fluid communicating means and said main diaphragm valve closes in response to control chamber pressure and by virtue of its own elastic memory, said pilot valve subassembly further including a movable chamber housing said pilot valve therewithin and being slidable axially within said control chamber through said opposite end thereof, said control chamber further comprising sealing means between said control chamber opposite end and said movable chamber of said pilot valve subassembly, and spring means urging said pilot valve subassembly chamber into engagement with said sealing means, said spring means being of a predetermined load whereupon in the event of a predetermined overpressure condition existing within said control chamber, said pilot valve subassembly chamber will move away from said sealing means to bleed overpressure fluid into said casing.
6. The breathing apparatus as claimed in claim 4 or 5 wherein said spring means is loaded to permit said pilot valve assembly chamber to move away from said sealing means when the pressure within said control chamber exceeds 150 percent of a predetermined pressure...
...5. In a breathing apparatus for supplying fluid under pressure to a user on demand and at ambient pressure, the breathing apparatus including a casing having an inlet for fluid under pressure, and an outlet for a user: a pilot valve and main valve assembly within said casing and connected to the inlet comprising a control chamber within said assembly, a main diaphragm valve subassembly segregating said control chamber from the breathing apparatus inlet, a pilot valve subassembly located within said control chamber at an end thereof opposite said diaphragm valve and means communicating fluid from said inlet to said control chamber whereby, in response to user demand, said pilot valve is opened to reduce pressure within said control chamber to open said main diaphragm valve and, upon termination of user demand, said pilot valve closes, pressure in said control chamber equalizes with inlet pressure through said fluid communicating means and said main diaphragm valve closes in response to control chamber pressure and by virtue of its own elastic memory, said pilot valve subassembly further including a movable chamber housing said pilot valve therewithin and being slidable axially within said control chamber through said opposite end thereof, said control chamber further comprising sealing means between said control chamber opposite end and said movable chamber of said pilot valve subassembly, and spring means urging said pilot valve subassembly chamber into engagement with said sealing means, said spring means being of a predetermined load whereupon in the event of a predetermined overpressure condition existing within said control chamber, said pilot valve subassembly chamber will move away from said sealing means to bleed overpressure fluid into said casing.
6. The breathing apparatus as claimed in claim 4 or 5 wherein said spring means is loaded to permit said pilot valve assembly chamber to move away from said sealing means when the pressure within said control chamber exceeds 150 percent of a predetermined pressure...
'Sorry, I just learned how to use size and the color to emphasize a point.
John