Indicating device for continuously indicating time to depletion of pressure tanks in use

Claim 2

An indicating device for automatically indicating the time to depletion of a pressure tank in use and comprising in combination: means continuously responsive to the pressure in said tank less the ambient pressure outside the tank and adapted to produce a continuous logarithmic output signAl indicative of said difference; means responsive to the rate of depletion of pressure in said tank to produce logarithmic output signals indicative of said responses; receiving means responsive to the difference between the two foregoing means for continuously indicating the time to depletion of pressure in said tank; and battery means for energizing electrically the aforesaid means.

Claim 3

An indicating device as described in claim 1 wherein said continuously responsive means comprise: a pressure transducer having external pressure transmitting means for continuously measuring ambient pressure, said transducer operatively connected to said tank for continuously measuring the difference between the pressure in said tank and the ambient pressure as measured by said bellows means; and signal means mounted in said pressure transducer and logarithmically responsive to said difference in pressures for signalling the logarithmic value of said difference.

Claim 4

An indicating device as described in claim 1 wherein said means responsive to the rate of depletion of pressure in said tank comprises: a second pressure transducer operatively connected by two lines to said pressure tank for comparing and signalling the respective differences between pressures at the beginning and end of a plurality of respectively similar periods; a second signal means mounted in said second transducer and logarithmically responsive to the respective differences between said pressures at the beginning and end of each of said periods for signalling the logarithmic values of said respective differences; a periodically operable valve means placed in one said line between said pressure tank and said second transducer for admitting and locking in tank pressure to said transducer at the beginning of each period and releasing it at the end of each said period; timing means mounted adjacent said rotary valve for partial use in driving said valve at a uniform rate or rotation; a rotary switch connected to said second transducer and also driven by said timing means for receiving said logarithmical values of said respective differences at the ends of said periods and passing them to said receiving means and cutting off signals at all other times.

Claim 5

Means responsive to the rate of depletion as described in claim 3 wherein said rotary switch is replaced with a diode for continuously passing the logarithmic values of respective differences between pressures to said receiving means and preventing the reverse.

Claim 6

Means periodically responsive to the rate of depletion as described in claim 3 wherein said timing means is a spring driven clock mechanism.

Claim 7

Means periodically responsive to the rate of depletion as described in claim 3 wherein said timing means is an electrically driven clock mechanism.

Claim 8

An indicating device as described in claim 1 wherein said receiving means comprises: first meter driving means, having a center shaft mounted for turning, said shaft being driven by said logarithmic output signals indicating difference in tank and ambient pressures for registering an angular displacement proportional to said signal; a second similar meter driving means its center shaft being driven by the rate of depletion logarithmic output signals; and anti-log. indicating means driven by said respective shafts and adapted to take the difference between said logarithmic output signals to there by divide tank pressure less ambient pressure by the rate of tank pressure depletion and read out time to depletion of the tank.

Claim 9

Receiving means as described in claim 7 wherein said anti-log. indicating means comprises: a circular member having a logarithmic scale arithmetically numbered applied around its perimeter and mounted to turn around a center axis and adapted to be so driven by one said meter shaft; and a pointer member mounted to turn on said center axis and adapted to be so driven in the same direction as said circular member, whereby the angular displacement from a common index mark of said circular member and said pointer results in the pointer member indicating on the scale of the circular member the time to depletion of said tank.

Claim 10

Continuously responsive means as described in claim 2 wherein said pressure transmission means is a bellows.

Claim 11

Continuously responsive means as described in claim 2 wherein said periodically operable valve means is a rotary valve.