Leakage detection system

• US 5,541,575 A
• Filed: 07/21/1994
• Issued: 07/30/1996
• Est. Priority Date: 07/23/1993
• Status: Expired due to Fees

• Current Assignee: Ulrich Virnich
• Original Assignee: Ulrich Virnich
• Inventors: Virnich, Ulrich
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US08/278,442
• Time in Patent Office: 740 Days
• Field of Search: 340/506, 340/605, 340/612, 340/618, 340/870.16, 340/870.17, 340/596, 73/290 R, 73/304 R, 137/386
• US Class Current: 340/506
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence
• CPC Class Codes: Y10T 137/7287 Liquid level responsive or maintaining systems

Abstract

A leakage detection system is provided having a plurality of locally distributed integrated units with a leakage sensor, preprocessing unit, and evaluation unit which connects with the individual integrated units or with a group of integrated units via a serial bus line. In each preprocessing unit, the value measured by the leakage sensor is subjected to a temperature compensation process.

Claims

1. A leakage detection system comprising:

at least one integrated unit having an individual, predetermined address code, the at least one integrated unit comprising a resistance measuring sensor electrically connected to a preprocessing unit, the preprocessing unit being defined at least by a resistance-to-voltage converter, an analog-to-digital converter, a transceiver, and a microcontroller, wherein at the location of the sensor, the preprocessing unit converts a predetermined measured resistance into a predetermined voltage by way of the resistance-to-voltage converter, and wherein the preprocessing unit converts the predetermined voltage into a predetermined digital signal by way of the analog-to-digital converter, the digital signal being stored in a memory of the microcontroller;

a serial data line disposed in signal communication with the at least one integrated unit; and

at least one evaluation unit disposed in signal communication, by way of the serial data line, with the at least one integration unit, wherein the at least one evaluation unit queries the at least one integrated unit for the predetermined digital signal, by a time multiplexing mode wherein the predetermined address code is transmitted by the evaluation unit, wherein upon receiving the predetermined address code, the integrated unit transmits the predetermined digital signal to the at least one evaluation unit, by way of the serial data line, for interpretation.

2. The leakage detection system of claim 1, wherein a monitoring unit is disposed in signal communication with the evaluation unit, the monitoring unit providing an alarm signal when the evaluation unit detects a leakage at at least one leakage sensor.

3. The leakage detection system of claim 1, wherein the resistance measuring sensor and the preprocessing unit are accommodated in a common housing.

4. A leakage detection system of claim 1, wherein the serial bus line is designed as an electrical two-wire line.

5. A process for calibrating a leakage detection system, the leakage detection system comprising at least one integrated unit having an individual, predetermined address code, the at least one integrated unit comprising a resistance measuring sensor electrically connected to a processing unit, the preprocessing unit being defined at least by a resistance-to-voltage converter, an analog-to-digital converter, a transceiver, and a microcontroller, wherein at the location of the sensor, the preprocessing unit converts a predetermined measured resistance into a predetermined voltage by way of the resistance-to-voltage converter, and wherein the preprocessing unit converts the predetermined voltage into a predetermined digital signal by way of the analog-to-digital converter, the digital signal being stored in a memory of the microcontroller;

a serial data line disposed in signal communication with the at least one integrated unit; and

at least one evaluation unit disposed in signal communication, by way of the serial data line, with the at least one integration unit, wherein the at least one evaluation unit queries the at least one integrated unit for the predetermined digital signal, by a time multiplexing mode, wherein upon receiving the predetermined address code, the integrated unit transmits the predetermined digital signal to the at least one evaluation unit, by way of the serial data line, for interpretation, the process comprising the steps of;

a) obtaining a predetermined digital signal for an environment not contaminated by a leakage substance;

b) storing the predetermined digital signal as a reference value; and

c) comparing the predetermined digital signal measured in a subsequent leakage monitoring process to the reference value.