US4896528A — Tank bottom leak testing and apparatus

Claim 1

Independent Claim 75 words

A grid network system for testing for leaks in the bottom of a tank which sits on a layer of soil which comprises: a plurality of perforated horizontal test conduits buried under said tank in said layer, means to provide an isolated area relative to at least one of said perforations in at least one of said test conduits; and means to measure any inflow and/or outflow of fluids to or from said isolated area.

Claim 2

Dependent Claim 75 words

A grid network system for testing for leaks in the bottom of a tank which sits on a layer of soil which comprises: a plurality of perforated horizontal test conduits buried under said tank in said layer, means to provide an isolated area relative to at least one of said perforations in at least one of said test conduits; and means to measure any inflow and/or outflow of fluids to or from said isolated area.

Claim 3

Dependent Claim 23 words

A system as defined in claim 1 in which said test conduits are parallel and corresponding perforations in said test conduits are aligned.

Claim 4

Dependent Claim 143 words

A grid network system for testing for leaks in the bottom of a tank which sits on a layer of soil which comprises: a plurality of perforated horizontal test conduits buried under said tank in said layer; said test conduits being parallel and corresponding perforations in said test conduits are aligned; an inert gas source; a first conduit means to inject gas from said gas source through a selected one of said test conduits to a selected perforation; first flow meter in said first conduit to obtain F i , inflow volume; second conduit means to fluidly connect corresponding perforation in the second test conduit to the exterior of said tank; a second flow meter in said second conduit means to obtain F o , out-flow volume; a first pressure gauge in said first conduit; a second pressure gauge in said second conduit.

Claim 5

Dependent Claim 143 words

A grid network system for testing for leaks in the bottom of a tank which sits on a layer of soil which comprises: a plurality of perforated horizontal test conduits buried under said tank in said layer; said test conduits being parallel and corresponding perforations in said test conduits are aligned; an inert gas source; a first conduit means to inject gas from said gas source through a selected one of said test conduits to a selected perforation; first flow meter in said first conduit to obtain F i , inflow volume; second conduit means to fluidly connect corresponding perforation in the second test conduit to the exterior of said tank; a second flow meter in said second conduit means to obtain F o , out-flow volume; a first pressure gauge in said first conduit; a second pressure gauge in said second conduit.

Claim 6

Dependent Claim 70 words

An apparatus as defined in claim 3 in which said first conduit means comprises: a first piston valve; a second piston valve spaced from said first piston valve; a nipple connecting said first and second piston valves and a perforation in said nipple; one end of said second piston valve being closed; a passage through said second piston valve so that gas may flow through said passage and said perforation.

Claim 7

Independent Claim 172 words

A method of testing for a leak in the bottom of a storage tank sitting on a layer of soil which comprises: determining the SBP (soil bearing pressure) of said layer; isolating an area under said bottom; establishing a first flow channel from said isolated area to the exterior of said layer beneath said tank; establishing a second flow channel from said isolated area to the exterior of said layer beneath said tank; flowing through said first channel, a first and a second quantity of an inert gas having a pressure P i1 and P i3 respectively in which P i1 is greater than said SBP; measuring the flow F i through said first flow channel of said first and second quantity; measuring the flow F o through said second flow channel at said pressure P i1 and again at P i3 ; using the values of F i , F o , P i1 , P i2 , and P i3 in determining the presence of a leak in said tank.

Claim 8

Independent Claim 172 words

A method of testing for a leak in the bottom of a storage tank sitting on a layer of soil which comprises: determining the SBP (soil bearing pressure) of said layer; isolating an area under said bottom; establishing a first flow channel from said isolated area to the exterior of said layer beneath said tank; establishing a second flow channel from said isolated area to the exterior of said layer beneath said tank; flowing through said first channel, a first and a second quantity of an inert gas having a pressure P i1 and P i3 respectively in which P i1 is greater than said SBP; measuring the flow F i through said first flow channel of said first and second quantity; measuring the flow F o through said second flow channel at said pressure P i1 and again at P i3 ; using the values of F i , F o , P i1 , P i2 , and P i3 in determining the presence of a leak in said tank.

Claim 9

Dependent Claim 24 words

A method as defined in claim 5 including the steps of plotting the measured values F o and F i on log log paper.

Claim 10

Dependent Claim 28 words

A method as defined in claim 5, including the step of injecting a sealant into said isolated area and maintaining said sealant under pressure until the sealant sets.

Claim 11

Dependent Claim 78 words

A valve system for isolating a perforation in test conduits having perforations placed in the soil beneath the bottom of a storage tank which comprises: a first cylindrical piston valve having an axial passage therethrough; a second piston valve; a conduit connected between said first piston valve and said second piston valve, said first conduit having a perforation therein; said first conduit connected to the said passage; and a second conduit connected to passage of first piston valve.

Claim 12

Dependent Claim 78 words

A valve system for isolating a perforation in test conduits having perforations placed in the soil beneath the bottom of a storage tank which comprises: a first cylindrical piston valve having an axial passage therethrough; a second piston valve; a conduit connected between said first piston valve and said second piston valve, said first conduit having a perforation therein; said first conduit connected to the said passage; and a second conduit connected to passage of first piston valve.

Claim 13

Dependent Claim 30 words

A valve arrangement as defined in claim 8 in which each said piston valve has elastomeric material on the exterior thereof for contacting the inner wall of said test conduits.

Claim 14

Dependent Claim 24 words

A valve system as defined in claim 9 in which said second conduit is provided with a pressure gauge and with a flow meter.

Claim 15

Independent Claim 115 words

An apparatus for testing for a leak in the bottom of a tank resting on a layer of soil which comprises: a plurality of perforated test conduits placed in said layer; means to isolate a selected one of said perforations in a selected test conduit to obtain a first selected perforation; first conduit means for injecting gas through said first selected perforation; means to isolate a second selected perforation in a selected test conduit; second conduit means to fluidly connect said second selected perforation to the exterior of said layer; there is thus formed a flow channel comprising a first conduit means, said first selected perforation, said second selected perforation, and said second conduit means.

Claim 16

Independent Claim 115 words

An apparatus for testing for a leak in the bottom of a tank resting on a layer of soil which comprises: a plurality of perforated test conduits placed in said layer; means to isolate a selected one of said perforations in a selected test conduit to obtain a first selected perforation; first conduit means for injecting gas through said first selected perforation; means to isolate a second selected perforation in a selected test conduit; second conduit means to fluidly connect said second selected perforation to the exterior of said layer; there is thus formed a flow channel comprising a first conduit means, said first selected perforation, said second selected perforation, and said second conduit means.

Claim 17

Independent Claim 91 words

A method of testing for a leak in the bottom of a storage tank sitting on a layer of soil which comprises: establishing a vacuum on at least a part of said layer under said storage tank by use of a vacuum pump; measuring the magnitude of the vacuum thus established; isolating said part of said layer from operation of said vacuum pump; determining the rate of change of said vacuum; using the rate of change of said vacuum to determine the existence or absence of a leak in the tank.

Claim 18

Independent Claim 91 words

A method of testing for a leak in the bottom of a storage tank sitting on a layer of soil which comprises: establishing a vacuum on at least a part of said layer under said storage tank by use of a vacuum pump; measuring the magnitude of the vacuum thus established; isolating said part of said layer from operation of said vacuum pump; determining the rate of change of said vacuum; using the rate of change of said vacuum to determine the existence or absence of a leak in the tank.

Claim 19

Independent Claim 145 words

An apparatus for testing for a leak in the bottom of a tank resting on a layer of soil which comprises: a plurality of perforated test conduits placed in said layer; means to isolate a selected one of said perforations in a selected test conduit to obtain a first selected perforation; first conduit means for injecting gas through said first selected perforations; means to isolate a second selected perforation in a selected test conduit; second conduit means to fluidly connect said second selected perforation to the exterior of said layer; there is thus formed a flow channel comprising a first conduit means, said first selected perforation, said second selected perforation and said second conduit means; first meter means to meter the flow of fluid in said first conduit means; and a second meter means to meter the flow of fluid in said second conduit means.

Claim 20

Independent Claim 145 words

An apparatus for testing for a leak in the bottom of a tank resting on a layer of soil which comprises: a plurality of perforated test conduits placed in said layer; means to isolate a selected one of said perforations in a selected test conduit to obtain a first selected perforation; first conduit means for injecting gas through said first selected perforations; means to isolate a second selected perforation in a selected test conduit; second conduit means to fluidly connect said second selected perforation to the exterior of said layer; there is thus formed a flow channel comprising a first conduit means, said first selected perforation, said second selected perforation and said second conduit means; first meter means to meter the flow of fluid in said first conduit means; and a second meter means to meter the flow of fluid in said second conduit means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-01-29	1993-07-31	1994-01-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-01-29	1997-07-31	1998-01-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-01-29	2001-07-31	2002-01-30	$7700.00	Window Closed / Lapsed

Tank bottom leak testing and apparatus

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