Leak detection method and system

Claim 2

Apparatus comprising: first flowmeter means for generating a first signal related to fluid flow at a first point in a conduit; second flowmeter means for generating a second signal related to fluid flow at a second point in said conduit: first comparing means for generating a first output signal related to the difference between said first signal and said second signal; second comparing means for generating a second output signal related to the difference between said first output signal and one of said first signal and said second signal.

Claim 3

The apparatus of claim 1 wherein: said first flowmeter means is upstream of said second flowmeter means; and said one of said signals is said first signal.

Claim 4

The apparatus of claim 1 including a scaler having a scaling factor related to the ratio of the maximum permissible volume of fluid leakage to the total volume of fluid flow.

Claim 5

The apparatus of claim 3 wherein said scaling factor is also related to the ratio of said first signal to said second signal at the same volume of fluid flow through said first and second flowmeter means.

Claim 6

The apparatus of claim 1 wherein: said first flowmeter is upstream of said second flowmeter; said one of said signals is said first signal; and said apparatus further includes a threshold detecting means for generating a third output signal when said second signal reaches a predetermined level.

Claim 7

The apparatus of claim 5 including a scaler having a scaling factor related to the maximum permissible ratio of the volume of fluid leakage to the total volume of fluid flow.

Claim 8

The apparatus of claim 6 wherein: said first signal is a series of electrical pulses having a pulse repetition rate related to the rate of fluid flow at said first point; said second signal is a series of electrical pulses having a pulse repetition rate related to the rate of fluid flow at said second point; said first output signal is a series of electrical pulses related in number to the difference between the number of pulses in said first and second signals; said scaling means generates an output signal comprising a series of electrical pulses related in number to the number of electrical pulses in said first signal; said second output signal is a series of electrical pulses related in number to the difference between the number of pulses in said first output signal and said scaling means output signal; and said threshold means generates a distinctive output signal when the number of pulses in said first output signal is greater than the number of pulses in said scaling means output signal.

Claim 9

Apparatus for comparing fluid leakage to fluid flow in a conduit comprising: means for generating a first electrical signal related to the volume of fluid flow at a first point in said conduit; means for generating a second electrical signal related to the volume of fluid leakage. between the first and a second point in said conduit; means for comparing said first and second electrical signals.

Claim 10

Apparatus for comparing fluid leakage to fluid flow in a conduit comprising: means for generating a first electrical signal related to the volume of fluid flow at a first point in said conduit; means for generating a second electrical signal related to the volume of fluid leakage. between the first and a second point in said conduit; means for comparing said first and second electrical signals.

Claim 13

The method of claim 9 including: generating a fifth electrical signal when said fourth electrical signal exceeds a predetermined reference level.

Claim 16

The method of claim 11 wherein the first and second signals are digital electrical signals; and, wherein the parameter of the fluid to which the second signal is related is the volume of fluid flow at a predetermined point.

Claim 17

The method of claim 12 wherein the first signal is generated by measuring the volume of fluid flow at two spaced points; and, wherein said predetermined point is the upstream one of the two spaced points.