Dispenser for Compressed Natural Gas (CNG) Filling Station
A fueling station dispenser for distributing a combustible gas that is lighter than air, and that includes electrical and gas handling sections in the same frame. A vapor barrier in the cabinet blocks fugitive gas that may be present in the gas handling section from entering the electrical section. According to most applicable codes, by isolating combustible gas from the electrical section gives it a Class I, Division 2 designation. Which eliminates the need to seal or air purge the electronics section as this designation allows for electronics that under normal intended operating conditions do not generate an arc with sufficient energy to initiate combustion.
The present application is a continuation of U.S. application Ser. No. 13/939,820, filed Jul. 11, 2013, and entitled “Dispenser for Compressed Natural Gas (CNG) Filling Station,” which claims priority to U.S. Provisional Application Ser. No. 61/725,366, filed Nov. 12, 2012, and entitled “Dispenser for Compressed Natural Gas (CNG) Filling Station,” each of which is hereby incorporated by reference herein in its entirety.
FIELD OF INVENTIONThe present disclosure relates in general to a device and method for dispensing fuels lighter than air, such as compressed natural gas (CNG). More specifically, the present disclosure relates to a gas dispenser having gas handling components and electronics in the same structure, and where the electronics are mounted in a non-purged housing spaced away from the gas handling components.
BACKGROUND OF THE INVENTIONTraditionally, vehicles have been fueled by one or more distillates of fuel oil, such as gasoline or diesel. Since these fuels have vapors that are heavier than air, the dispensers for these fuels were designed with the electronics located above the fuel-handling, hazardous area. This allowed the dispenser structure to be broken into different hazardous area classifications allowing electronics to be located in the structure with minimal safeguards from the flammable vapors below. Recently, a growing number of vehicles have been manufactured, or converted, to operate on compressed natural gas (CNG), which is lighter than air, instead of the heavier than air longer chain hydrocarbons. The availability, low cost, and lower emissions of combusting natural gas over fuel oil distillates have garnered interest in continuing to increase the number of natural gas powered vehicles. Similar to typical gasoline or diesel fueling dispensers, CNG fueling dispensers, whose structure contains piping and valves for delivering gas to a customer, have been designed using similar dispenser structures with the electronics, which control the dispenser and payment authorization terminals, above the gas handling components.
Standards for the safe handling of CNG have been published by national code recommending bodies. Many states have adopted these codes in their respective vehicle, transportation, and building regulations. As CNG is lighter than air, unlike gasoline or diesel vapors, CNG that may escape from the gas handling components can rise; and thus present different hazardous zones for a CNG dispenser as compared to a gasoline or diesel dispenser. As such, standards for CNG dispensers reflect a different hazardous zone rating as compared to gasoline or diesel dispensers in these standards. For example, explosive vapors may sometimes concentrate in spaces above a gas handling portion of a CNG dispenser having a traditional gasoline or diesel dispenser design. By most standards, the spaces normally having the explosive vapor concentration would be deemed Class I, Division 1, thus prohibiting any device capable of producing a spark. For example, applicable codes typically designate Class I locations to be where a flammable gas or vapor may be present in a sufficient amount to produce an explosion or ignitable mixture. Class I locations are sometimes designated as Division 1 when the flammable gas is likely to exist, such as in quantities sufficient to produce an explosive or ignitable mixture under normal operating conditions. Class I locations are sometimes designated as Division 2 when the flammable gas is not normally present in an explosive concentration, but accidentally exists. Some CNG dispensers having traditional gasoline or diesel dispenser structures address this change in hazardous rating by enclosing electronics in an explosion-proof junction box, including an Intrinsic Safe Barrier (ISB), or disposing electronics in an air purged enclosure protected through pressurization. There are some components used in payments terminals that either due to the need of accessibility to the customer or because of the type of component, cannot be adequately protected by an explosion-proof junction box or an ISB. When this is true, these components are normally protected by an air purge system. Correctly implemented, an air purge system can change the area within the enclosure to a non-hazardous, or unclassified area. Air purge systems can be affected by ambient pressure variations and wind. An air purge system also exposes the electronics to cold and/or moist air that can affect the operation of the components as well as corrode or damage them. It can also inject dirt into the system. The fans used for the source of air for air purge systems must be positioned in a location away from the hazardous area that is created by the dispenser, which increases installation costs and complexity.
SUMMARY OF THE INVENTIONDisclosed herein are embodiments of a dispenser for handling a combustible gas. In one embodiment the dispenser includes a frame, an electrical section, and a gas handling section. Further included in the frame is a vapor barrier that blocks fugitive gas from entering into the electronics section. Example vapor barriers include a bulkhead in the gas handling section, a bulkhead in the electronics section, a housing for electronics in the electrical section, and combinations thereof. Without the rating whereby an explosive mixture of gas normally is in the electronics section, electronics can be deployed that do not create an arc during their normal operation with sufficient energy to initiate combustion. Also optionally included is a vent system that includes side columns for venting fugitive gas from the gas handling section to ambient and that bypasses the electronics section.
Some of the features and benefits of embodiments of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTIONA method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. Embodiments of the method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.
It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
In one example, a vapor barrier between the gas handling section 12 and the electronics section 14 removes paths of fugitive gas flow between these sections 12 and 14. As such, electronics section 14 is not in a Class I, Division 1 zone as specified in the code. Instead the electronics section 14 is designated as a Class I, Division 2 zone per code. The less restrictive Class I, Division 2 zone definition expands the options of electronics that can be in electronics section 14. For example, absent isolating gas handling section 12, to comply with code, electronics in section 14 must be protected by an explosion-proof housing, and ISB circuit, or an air purge system. Instead, by isolating electronic section 14 in a separate housing whose structure is independent from the gas handling housing, code compliance for a Class I, Division 2 zone is achieved without the use of explosion-proof enclosures, an ISB or an air purge system.
A housing 34 is illustrated in the frame 16 in a space that is on a side of the bulkhead 32 opposite the gas handling section 12. In the example of
In the example of
Further illustrated in the example of
Shown in a perspective partially exploded view in
Embodiments of the present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. For example, embodiments exist where compliance with applicable codes is maintained by providing a single vapor barrier (one or more of bulkheads 32, 35 or housing 34) between the gas handling and electronic sections 12, 14. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.
Claims
1. A dispenser for handling compressed gas comprising:
- a frame;
- a gas handling section in the frame;
- an electronics section in the frame; and
- a vapor barrier in the frame, so that when fugitive gas is in the gas handling section, the fugitive gas is blocked from flowing into the electronics section by the vapor barrier.
2. The dispenser of claim 1, wherein the vapor barrier comprises a bulkhead in the frame that defines an upper terminal end of the gas handling section.
3. The dispenser of claim 1, wherein the vapor barrier comprises a bulkhead disposed in the frame above the gas handling section.
4. The dispenser of claim 1, wherein the vapor barrier comprises a housing in the electronics section and in which electronics are disposed.
5. The dispenser of claim 2, further comprising an electrical conduit extending between the electronics section and the gas handling section and through the bulkhead.
6. The dispenser of claim 1, wherein the gas comprises compressed natural gas.
7. The dispenser of claim 1, further comprising side columns in the frame that extend adjacent the gas handling section and to above the electronics section, an opening in a sidewall of the gas handling section, and a vent in a sidewall of each of the side columns, so that fugitive gas in the gas handling section can flow through the opening, along the side columns, and through the vents to outside of the frame and past the electronics section.
8. The dispenser of claim 1, wherein the gas handling section is defined as a Class I, Division 1 area, and the electronics section is defined as a Class I, Division 2 area.
9. A dispenser for use with a combustible gas comprising:
- a frame;
- a gas handling section in the frame in communication with a supply of combustible gas; and
- an electronics section in the frame in signal communication with the gas handling section;
- a vapor barrier in the cabinet that defines an obstacle to a free flow of fugitive gas to within the electronics section; and
- a vent system in which fugitive gas from the gas handling section selectively bypasses the electronics section.
10. The dispenser of claim 9, wherein the vapor barrier comprises a bulkhead mounted in the frame.
11. The dispenser of claim 10, wherein the bulkhead is in the gas handling section.
12. The dispenser of claim 10, wherein the bulkhead is in the electronics section.
13. The dispenser of claim 9, wherein the vapor barrier comprises a housing in the electronics section, and wherein electronics are disposed in the housing that only during unexpected conditions are the electronics capable of producing an arc having sufficient energy to initiate combustion.
14. The dispenser of claim 9, wherein the vent system comprises vertical open spaces housed in side columns on lateral sides of the frame, openings that extend through sidewalls of the gas handling section and that intersect with the vertical open spaces, and vents in the side columns on a side of the electronics section opposite the gas handling section, and that define a communication path between the vertical open spaces and ambient.
15. A dispenser for handling a combustible gas comprising:
- a cabinet;
- a gas handling section in the cabinet that comprises a line in communication with a source of combustible gas, and that is in selective communication with a nozzle outside of the cabinet;
- an electronics section in the cabinet;
- a first bulkhead in the gas handling section that defines a first vapor barrier;
- a second bulkhead in the electronics section that defines a second vapor barrier; and
- a housing in the electronics section having electrical hardware disposed therein and that defines a third vapor barrier.
16. The dispenser of claim 15, having electrical hardware that can produce an arc having sufficient energy to initiate a combustion only during unexpected operation.
17. The dispenser of claim 15, further comprising an air gap between the gas handling section and the housing and an air gap between side wall of the cabinet and the housing.
18. The dispenser of claim 15, wherein the gas is lighter than air.
Type: Application
Filed: Nov 20, 2015
Publication Date: May 31, 2018
Inventors: Randy A. Moses (Palm, PA), Kent W. Robinson (Quakertown, PA)
Application Number: 14/946,926