Patent Application
20160003685
The present invention relates to monitoring skin temperature of a tubular member in which a hot fluid is flowing. More particularly, the present invention relates to a mounting apparatus for a temperature sensor assembly for sensing the skin temperature of the tubular member.
A fired heater is a direct-fired heat exchanger that uses the hot gases of combustion to raise the temperature of a feed flowing through coils of tubes aligned throughout the heater. Depending on the use, these are also called furnaces or process heaters. Some heaters simply deliver the feed at a predetermined temperature to the next stage of the reaction process; others perform reactions on the feed while it travels through the tubes.
Fired heaters are used throughout the hydrocarbon and chemical processing industries such as refineries, gas plants, petrochemicals, chemicals and synthetics, olefins, ammonia and fertilizer plants. Most of the unit operations require one or more fired heaters, as a startup heater, fired reboiler, cracking furnace, process heater, process heater vaporizer, crude oil heater or reformer furnace.
For production, safety and quality control, to name a few, it is often necessary to measure the skin temperature of tubes entering, within and exiting a heat source in a consistent and coincident manner. For example in the chemical processing industry, these temperatures can range from hundreds to thousands of degrees Fahrenheit. Furthermore, the nature of the heat generating furnaces/heaters is that they are often subject to vibration. This characteristic complicates fixed temperature sensors from taking consistent measurements; for example humans taking the temperature with a hand-held temperature “gun” consistently have an issue with pointing the laser at the same spot every time. In this regard most thermocouples measure temperature via the institution of a laser that points at the item being measured. Consistent measurements demand that this laser point be placed at almost exactly the same spot when taking a temperature reading so as to obtain consistent and comparable results. Coupled with the fact that very often the tubes, the skin temperatures of which are to be measured, are outside and therefore are exposed to adverse weather conditions, the apparatus employed to take the skin temperature must be somewhat resistant to weather elements e.g., wind, rain, snow etc.
In one aspect the present invention provides a mounting apparatus for a temperature sensor assembly.
In another aspect the present invention relates to a mounting apparatus for a temperature sensor assembly which is heat and weather resistant.
In still another aspect the present invention provides a mounting apparatus for a temperature sensor assembly which can measure the skin temperature of a metallic body e.g, a tubular member in which is contained a hot fluid.
In still a further aspect, the present invention provides a mounting apparatus for a temperature sensor assembly wherein the temperature sensor assembly is maintained in a fixed position relative to the surface of a metallic body e.g., a tubular member in which a hot fluid is flowing.
These and further features and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.
The term “collar” as used herein refers to any structure which encircles at least one tubular member and can include a structure which itself is not necessarily circular when viewed in cross-section i.e., it is not necessarily an annular body, but which has one or more openings therethrough in which can be received one or more tubular members.
While in the description which follows, the mounting apparatus of the present invention will be described with respect to the use of an outer wrap, sheath or jacket which is heat and weather resistant, it is to be understood that the invention is not so limited. There may be circumstances when such a weather proof wrap is unnecessary. Further, while the invention will be described with reference to the inlet/outlet tube of the convection section of a typical gas fired heater/furnace, it will be understood that it is not so limited. For example, the mounting apparatus of the present invention could be used on the inlet/outlet tubes of the radiant section of the heater/furnace. Moreover, it will be apparent that the present invention can be used to mount any sort of temperature sensing or temperature sensor assembly on any conduit through which heated fluids/slurries etc. are being transported. Thus, the word “tubular” or variants thereof is not intended to be limited to a conduit or the like having a circular cross section as opposed to any conduit, regardless of its cross sectional configuration.
Referring first to
It will be appreciated that while in the embodiment shown in
Referring now to
As best seen with reference to
To hold wrap 26 securely onto tubular member 22, wrap 26 is provided with straps 30 and 32 on opposite ends of wrap 26, straps 30 and 32 being provided with D-rings 34 and 36, respectively, for size adjustability. In this regard it should be noted as best seen in
Referring now to
Various types of refractory materials can be employed to make the collars of the present invention. As known to those skilled in the art, refractories can generally be classified as acid refractory materials, natural refractory materials, and basic refractory materials. Generally speaking, the environment in which the apparatus of the present invention is used will dictate the type of refractory material used in manufacturing the collar. As is known to those skilled in the art, since the collars of the present invention, are formed objects, as opposed to unformed granulated or plastic compositions, the raw materials selected to form the collars are mixed and formed into the desired shape, either via vacuum forming or thermoforming processes well known to those skilled in the art. In some cases, the thus formed product can be milled, ground, or sandblasted to achieve the precise size and shape desired.
In cases where the collar formed by segments 52 and 54 was not exposed to the elements e.g., if apparatus 24 extended into an enclosure for some reason and thus a weather resistant wrap such as wrap 26 was not needed, segments 52 and 54 could be held in place by means of one or more bands of a suitable material which encircled the segments to maintain the collar formed by the segments intact. It will also be appreciated that other means of connecting segments 52 and 54 could be employed as for example by the use of nut and bolt assemblies received through registering bores in segments 52 and 54.
Referring now to
As can be seen, orifice 50 in sheath 26 is in register with throughbore 70 in segment 54 as well as the openings in anchor plate 86 and mounting plate 82. It should also be noted that orifice 50 in jacket 26 is formed in a portion of jacket 26 which is received in a depression 100 formed in the outer surface of segment 54.
Temperature sensor assembly 55 includes a compression fitting 102 which connects a lead 104 to housing/cap 78, lead 104 being attached in a well known manner to a readout/recording system e.g., a computer, recorder, gauge or the like which shows and/or records the temperature detected by probe 76.
Referring now to
While as shown and described above, the connector or connection between temperature sensor assembly 55 and the mount comprises a threaded opening in the mounting plate 82, it will be appreciated that other connectors or connection assemblies may be employed. For example, so-called quick connect or push fit connectors or couplings may be employed as well as other types of connection assemblies well known to those skilled in the art. The only requirement for the connector or connection between the apparatus of the present invention and the temperature sensor assembly is that it possess the ability to hold the probe of the temperature sensor assembly firmly and securely in place on the mount of the apparatus of the present invention.
To the extent possible, it is desired that the end of probe 76, regardless of its nature be as close as possible to the outer surface of the tube 22 so as to obtain the most accurate skin temperature measurement. Thus the mounting assembly of the present invention can be used with various types of thermocouples and temperature sensor assemblies. For example both contact thermocouples and optical thermocouples can be mounted using the apparatus of the present invention. A particularly useful temperature sensor assembly is sold under the trade name Exactus® by BASF. Depending upon the temperature sensor assembly employed, the end of the probe can be spaced from the skin of the tube to be measured or be held against the tube. In the case of temperature sensing assemblies wherein the probe is against the tube, provision is made for expansion of the tubes to prevent damage to the probe.
Although specific embodiments of the invention have been described herein in some detail, this has been done solely for the purposes of explaining the various aspects of the invention, and is not intended to limit the scope of the invention as defined in the claims which follow. Those skilled in the art will understand that the embodiment shown and described is exemplary, and various other substitutions, alterations and modifications, including but not limited to those design alternatives specifically discussed herein, may be made in the practice of the invention without departing from its scope.
