Temperature measuring and monitoring

Details Temperature measuring and monitoring Temperature measuring and monitoring

1999-01-26

2001-04-17

Gutierrez, Diego (Department: 2859)

Thermal measuring and testing

Leak or flaw detection

C374S137000, C374S184000, C340S870170

Reexamination Certificate

active

06217211

ABSTRACT:

FIELD OF THE INVENTION
The invention concerns a temperature measuring and monitoring system for leak detection on pipelines.
BACKGROUND OF THE INVENTION
There are many different methods for locating leaks in pipelines, including those methods which are based on the variation in temperature when leaks occur. In German patent application DE 30 49 544 A1 sensors in respect of temperature, moisture and radioactivity are arranged between the pipeline wall and the insulation and are connected to an analysis station by way of optical waveguides or fiber optics. Many sensors and accordingly many optical waveguides are needed in order to analyze propagation of the leakage. The handling of such optical waveguides in the ground gives rise to problems.
German patent application DE 195 09 129 A1 describes a further known method and apparatus for checking and monitoring the condition of pipes, containers, vessels, pipelines or the like, wherein local fluctuations in temperature are detected. This involves establishing the ambient temperature distribution over portions of the item to be monitored, and using an elongate temperature sensor for distributed temperature measurement. When a local anomaly is detected in the temperature distribution, it is concluded that there is a leak. For establishing the ambient temperature distribution, use is made of an optical-fiber sensor cable which is operated with laser light, and evaluation in respect of transit time and intensity of the backscattered laser light is implemented. That mode of temperature detection is subject to error sources which vary with time so that reliable evaluation over long periods of time becomes difficult.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel temperature measuring and monitoring system for leak detection in pipelines. It is a further object of the invention to keep drifts in temperature measurement at a low level or even to eliminate such drifts.
With the present invention, a number of temperature sensors are provided which each have a measuring member and a reference member. The measuring member is included as a frequency-determining member in a measuring oscillator which is of the RC- or LC-type and the reference member is included as a frequency-determining member in a similar RC- or LC- reference oscillator. Such oscillators have active components; which are disposed on a common carrier and are made up of similar materials or comprise materials which age in a similar manner. Associated with each sensor is a communication unit which has transmitting and receiving units in order to respond upon receipt of an associated address so as to interrogate the temperature sensor. In that situation the oscillator frequency of the reference oscillator and of the measuring oscillator is sent to an evaluation circuit which evaluates the measuring frequency to determine the temperature at the measuring member. A mathematical function including the measuring frequency and the reference frequency is used to correct the respective provisionally acquired temperature value and to substantially eliminate drifts in respect of temperature measurement.
In the case of extended items as pipelines and pipeline systems are, groups of temperature sensors and associated communication units are formed and are connected by way of a serial connecting line having two or three wires. Associated with each group is a group computer as an evaluation circuit for each serial connecting line and the group computer operates each temperature sensor with its address allocated thereto and interrogates it in order to compare temperature values obtained in that way to predetermined temperature values. In that fashion, anomalies in temperature distribution at the item to be monitored are detected.


REFERENCES:
patent: 3413840 (1968-12-01), Basile et al.
patent: 4422066 (1983-12-01), Belcourt et al.
patent: 4441107 (1984-04-01), Chaborski et al.
patent: 4553432 (1985-11-01), Barlian et al.
patent: 4816748 (1989-03-01), Tazawa et al.
patent: 4861168 (1989-08-01), Ziegler et al.
patent: 4874252 (1989-10-01), Ziegler et al.
patent: 4878226 (1989-10-01), McQuoid et al.
patent: 5862170 (1999-01-01), Britton, Jr. et al.
patent: 6091255 (2000-07-01), Godfrey
patent: 2236914 (1973-03-01), None
patent: 0 060 552 A2 (1982-09-01), None
patent: 0 073 322 A1 (1983-03-01), None
patent: 30639 (1981-03-01), None
patent: 71126 (1990-03-01), None
patent: 547651 (1977-02-01), None

Affiliated with

Also associated with

Rating

Temperature measuring and monitoring does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Temperature measuring and monitoring, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temperature measuring and monitoring will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2507137