Pneumatic control system and reset valve for such a system or the like

Claim 2

A pneumatic control system comprising a pair of condition controller means each having a sensor and a bleed-type pneumatic valve operated thereby, a source of control fluid having two different control pressure levels, a pneumatically operated device, relay means operatively interconnected to said source for directing a branch signal of said control fluid to said pneumatically operated device in relation to a pilot signal directed to a pilot chamber of said relay means by said controller means, first passage means for interconnecting said source to said valve of one of said controller means, second passage means for interconnecting said source to said valve of the other of said controller means, pressure responsive means in said first passage means for preventing fluid communication therethrough when said source is at one pressure level thereof and permitting fluid communication therethrough when said source is at its other pressure level, third passage means adapted to interconnect said first passage means intermediate said pressure responsive means and said one controller means to said pilot chamber and adapted to interconnect said second passage means to said pilot chamber, switching means in said third passage means having one position for interconnecting only said second passage means to said pilot chamber whereby the pilot signal for said relay means is provided only by said other controller means and having another position for interconnecting only said first passage means to said pilot chamber whereby the pilot signal for said relay means is provided only by said one controller means, and reset means in said first passage means intermediate said pressure responsive means and said one controller means for switching said switching means from said other position thereof to said one position thereof when said source is at its said other pressure level.

Claim 3

A pneumatic control system as set forth in claim 1 wherein said switching means has means for automatically moving to said other position thereof to interconnect said first passage means to said pilot chamber of said relay means when said pressure responsive means provides fluid communication through said first passage means by said source providing said other pressure level thereof and for moving to said one position thereof when said pressure responsive means prevents fluid communication through said first passage means by said source providing said one pressure level thereof.

Claim 4

A pneumatic control system as set forth in claim 2 wherein said automatic means of said switching means comprises pneumatically operated valve means.

Claim 5

A pneumatic control system as set forth in claim 3 wherein fourth passage means interconnect said first passage means intermediate said pressure responsive means and said one controller means to said pneumatically operated means of said switching means and to said pneumatically operated valve means.

Claim 6

A pneumatic control system as set forth in claim 4 wherein said pneumatically operated valve means comprises a valve seat interconnected to said fourth passage means, a pneumatic actuator, and movable lever means operatively associated with a valve member means for opening and closing said valve seat, said lever means being operatively interconnected to said actuator to be moved thereby.

Claim 7

A pneumatic control system as set forth in claim 4 wherein said pneumatically operated valve means comprises a valve seat interconnected to said fourth passage means, a pneumatic actuator, and movable lever means operatively associated with a valve member means for opening and closing said valve seat, said lever means being operatively interconnected to said actuator to be moved thereby.

Claim 8

A pneumatic control system as set forth in claim 3 wherein a fourth passage means interconnects said first passage means intermediate said pressure responsive means an said one controller means to said pneumatically operated valve means.

Claim 9

A pneumatic control device comprising a housing means, a pair of condition controller means carried by said housing means and each having a sensor and a bleed-type pneumatic valve operated thereby, said housing means having a relay means therein adapted to be interconnected to a pneumatic source of control fluid having two different control pressure levels for directing a branch signal of said control fluid to a pneumatically operated device in relation to a pilot signal directed to a pilot chamber of said relay means by said controller means, first passage defining means in said housing means adapted to interconnect said source to said valve of one of said controller means, second passage defining means in said housing means adapted to interconnect said source to said valve of the other of said controller means, pressure responsive means in said first passage means of said housing means for preventing fluid communication therethrough when said source is at one pressure level thereof and permitting fluid communication therethrough when said source is at its other pressure level, third passage defining means in said housing means adapted to interconnect said first passage means intermediate said pressure responsive means and said one controller means to said pilot chamber and adapted to interconnect said second passage means to said pilot chamber, switching means in said third passage means of said housing means having one position for interconnecting only said second passage means to said pilot chamber whereby the pilot signal for said relay means will be provided only by said other controller means and having another position for interconnecting only said first passage means to said pilot chamber whereby the pilot signal for said relay means will be provided only by said one controller means, and reset means in said first passage means intermediate said pressure responsive means and said one controller means for switching said switching means from said other position thereof to said one position thereof when said source is at its said other pressure level. 9 A pneumatic control device as set forth in claim 8 wherein said switching means has means for automatically moving to said other position thereof to interconnect said first passage means to said pilot chamber of said relay means when said pressure responsive means provides fluid communication through said first passage means by said source providing said other pressure level thereof and for moving to said one position thereof when said pressure responsive means prevents fluid communication through said first passage means by said source providing said one pressure level thereof.

Claim 10

A pneumatic control device as set forth in claim 9, wherein said automatic means of said switching means comprises pneumatically operated means and wherein said reset means comprises pneumatically operated valve means.

Claim 11

A pneumatic control device as set forth in claim 10 wherein fourth passage defining means is provided in said housing means and interconnects said first passage means intermediate said pressure responsive means and said one controller means to said pneumatically operated means at said switching means and to said pneumatically operated valve means.

Claim 12

A pneumatic control device as set forth in claim 10 wherein said pneumatically operated valve means comprises a valve seat interconnected to said fourth passage means, a pneumatic actuator, a movable lever means operatively associated with a valve member means for opening and closing said valve seat, said lever means being operatively interconnected to said actuator to be moved thereby.

Claim 13

A pneumatic control device as set forth in claim 8 wherein said reset means comprises a pneumatically operated valve means which closes when said pressure responsive means permits fluid communication through said first passage means, said reset means having manual means for opening said valve means when the same is closed by said pressure responsive means.

Claim 14

A pneumatic control device as set forth in claim 13 wherein said housing means has a fourth passage means that interconnects said first passage means intermediate said pressure responsive means and said one controller means to said pnEumatically operated valve means.