Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Chemical analysis
Reexamination Certificate
2001-09-13
2003-03-25
Barlow, John (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Chemical analysis
C702S050000, C702S055000, C073S863110, C073S863840
Reexamination Certificate
active
06539312
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to sample probes of the type which may be used in a gas sampling system. More particularly, the present invention relates to an improved heated gas sampling probe for obtaining a highly accurate sample of gas hydrocarbons passing through a pipeline.
BACKGROUND OF THE INVENTION
A gas sampling system for gas pipelines normally includes a probe, a sample pump and a sample collection bottle. The pump transmits the gas to be sampled through the probe and to the bottle. Sample probes for obtaining gas samples from pipelines normally include a body with a shut off valve along a throughbore, with the lower body threads connected to the pipeline. Extending downward from the body is a lower tubing section, which typically was welded to the body to provide the length necessary for the end of the sample probe to reach the inner third of the cross-section of the pipeline in which it is mounted.
In order to obtain a proper gas sample from the pipeline to the bottle, the sampling equipment between the pipeline and the collection bottle is required to be at a temperature above the dew point of the hydrocarbon gas. When ambient conditions are below the hydrocarbon dew point, it is necessary to apply heat from a heating source to the sampling equipment, including particularly the pump, which then conventionally heats the probe by conduction. The probe may alternatively be heated directly by the heating source. Heating of the sampling equipment may be accomplished by heat trace lines, either electrical or water, or by heating with a catalytic heater that uses pipeline gas for firing the heater to heat the pump and probe by radiant heating. These prior art heating devices have not, however, been capable of selectively heating the full length of the throughbore in the probe, including particularly the full length of the lower probe within the pipeline. Accordingly, the sampled gas temperature drops below its dew point, and the collection bottle does not accurately reflect the BTU content of gas in the pipeline.
Due to the problems with obtaining accurate gas samples in a sample bottle from a hydrocarbon pipeline, it is known to enclose the heater for heating the pump and the associative flow lines from the gas pipeline to the sample bottle. In some cases, the pump and heating system have been enclosed within a relatively large enclosure or“dog house” which includes a portion of the length of the pipeline. The cost of these enclosures is significant, however, and it is generally difficult to provide proper service to the components within the enclosure without removing the entire enclosure from the pipeline.
It is desirable that a sampling system be provided that easily accomplishes heating of the sampling equipment, including particularly the full length of the throughbore in the probe, to a temperature above the dew point of the hydrocarbon gas being sampled.
The disadvantages of the prior art are overcome by the present invention, and an improved sampling system is hereafter disclosed which includes a probe designed to maintain the hydrocarbon gas passing through the probe above it dew point.
SUMMARY OF THE INVENTION
The present invention is directed to a gas sampling system and associated equipment which utilizes a probe supporting the pump and a heater for heating the pump and the probe to a temperature above the dew point of the hydrocarbon gas being sampled. The heater typically heats a pump which then heats the probe by conduction, since both the pump and the probe have metallic bodies. The gas sampling equipment is preferably housed within an enclosure or compartment which contains the pump, the probe, and the sample bottle. A catalytic heater may be used as the heater, and housed in the compartment and fired by gas from the pipeline. Due to improvements in the probe, the heater is particularly effective in thoroughly heating the full length of the throughbore in the probe, including its lower body within the pipeline.
The probe of the present invention comprises a body which preferably supports the enclosure thereon. The probe may be mounted on a pipeline by threading within an internally threaded opening in a weld flange on the pipeline. A lower body of the probe extends within the pipeline a distance ⅓ the inner diameter of the pipeline. The outer diameter of the lower body of the probe is at least about 80% of the inner diameter opening in the weld flange of the pipeline through which it passes when mounted on the pipeline. Fins for increasing the thermal conductivity to the gas passing through the probe are formed by threads on the external surface of the lower body. Thus, the lower body has a relatively large external surface area for high thermal conductivity from the gas in the pipeline to the sampled gas in the throughbore in the lower body.
An intermediate body of the probe may be externally threaded for mounting within the internally threaded opening of the weld flange for the pipeline. An upper body of the probe extends outwardly from the pipeline and preferably has an outer diameter at least 50% greater, and preferably about twice, the inner diameter of the internally threaded opening in the pipeline. A substantial length portion of the upper probe section outwardly of the pipeline is externally threaded to provide a relatively long threaded portion for connection to the enclosure which houses the pump and the probe. The probe is preferably fabricated from a high thermal conductivity metal, and may be made of anodized aluminum having a conductivity in excess of 80 BTU/Ft Hr/Ft
2
/° F. The relatively large cross-section of the upper probe body provides a large thermal flow path from the heating source to the lower probe body at a rate that overcomes other thermal influences.
An object of the invention is the provision of an elongate probe and heater for effectively heating the probe along its entire length for use in a gas sampling system for sampling hydrocarbon gas in a pipeline.
It is a feature of the invention that the probe may support an enclosure for the sampling equipment mounted on and carried by the probe.
It is a feature of the invention that the probe is fabricated in high thermal conductivity metal, such as anodized aluminum.
A further feature is that the probe has a relatively large diameter upper probe body extending outwardly from the pipeline to provide a large thermal cross-sectional flow path from the heating source to the lower probe body within the pipeline.
A further feature of the invention is that the outer diameter of the lower body of the probe within the pipeline is greater than at least about 80% of the inner diameter of the opening in the pipeline, thereby providing a high cross-sectional flow area for conduction of heat from an upper body of the probe to a lower body within the pipeline.
These and further objects, features and advantages of the invention will be apparent from the following description, wherein reference is made to the Figures in the accompanying drawings.
REFERENCES:
patent: 5092742 (1992-03-01), Allen et al.
patent: 5109709 (1992-05-01), Nimberger
patent: 5191801 (1993-03-01), Allen et al.
patent: 6289752 (2001-09-01), Nimberger et al.
Cessac Kevin J.
Nimberger Spencer M.
Barlow John
Browning & Bushman P.C.
Helmreich Loren
PGI International, Inc.
Vo Hien
LandOfFree
Sampling system for obtaining pipeline gas samples does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sampling system for obtaining pipeline gas samples, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sampling system for obtaining pipeline gas samples will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3046043