Patent Application
20140109823
1. Field of the Invention
The present invention relates to pressure indicators, and in particular, to a pressure indicator that can be used to indicate the presence of potentially-dangerous pressure inside a tank or other container that holds natural gas or any other gas.
2. Description of the Prior Art
Gaseous fuels are becoming more common as energy sources. Examples include hydrogen and compressed natural gas (CNG), which have been used to power vehicles. As such, there is a need for high pressure storage being required to meet the energy density requirements for such gaseous fuels. Much of the text could be the same with the substitution of “fuel gases” for “hydrogen”.
However, the storage of fuel gases can be challenging. Currently, fuel gases are stored in high pressure containers or vessels. These vessels must be large and are subject to stresses and strains during each pressurization cycle, leading to material fatigue and a reduction in strength. These vessels include a valve through which the gas can be delivered.
Recently, a fatality occurred when an individual removed the valve of a CNG storage vessel that was still under pressure. Other injuries and deaths have occurred while people have worked on pressure vessels under the mistaken assumption that the vessel has been depressurized.
In this regard, conventional fuel gas storage vessels are not equipped with a gauge. Instead, they have a pressure transducer that sends a signal to the fuel gauge, but in the case involving the fatality, it was probably not used. Once the storage vessel is removed from the vehicle, the transducer is not usable without special equipment. In addition, transducers are also quite often placed on an outlet port of the valve and does not indicate internal pressure when the valve is closed.
Servicing of pressure vessels can present a high risk to personnel and property if not depressurized properly prior to servicing or disposal. Current methods for creating safe conditions for servicing pressure vessels are based on procedural instructions for depressurization. However, these do not provide a positive or clear indicator that the vessel has truly been depressurized, or that the procedures were followed accurately.
Thus, there still remains a need to properly warn an individual that a pressure vessel has not been completely depressurized.
It is an object of the present invention to provide an indicator that clearly warns an individual that a pressure vessel or container has not been completely depressurized.
In order to accomplish the objects of the present invention, a pressure indicator system is provided for use with a gas storage container. The gas storage container has an interior that stores gas, and a housing having a cavity that opens to atmosphere and which communicates with the interior of the container. A piston or diaphragm communicates with a stem that extends through the cavity and into atmosphere, with the stem having a pressure indicator provided around an upper portion of the stem. A resilient element is retained in the cavity and normally biases the piston or diaphragm towards the interior of the container. The existence of pressure in the container opposes the normal bias of the resilient element to cause the stem and its pressure indicator to extend outside the cavity. In this regard, the present invention provides a visible indicator at the point of danger without requiring the use of external equipment.
The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.
The container 10 and the valve assembly 12 can be constructed in a manner similar to conventional containers and valves, except that the container 10 is provided with a pressure indicator system 14, as shown in
The pressure indicator system 14 utilizes a piston 20 that has a seal 22 (e.g., an O-ring) positioned about a circumferential channel defined by the two walls 24 and 26 of the piston 20. A shaft or stem 28 extends from the top of the upper wall 26, and a resilient element 30 (e.g., a spring) is provided around the stem 28. A pressure indicator 32 is wrapped around an upper portion of the stem 28. The pressure indicator 32 should be a simple element that attracts attention, such as a red-colored band, so that the user can quickly and easily see that pressure still remains in the container 10.
The piston 20 and its stem 28 are positioned inside a cavity 40 provided in the housing 11 of the fitting, valve assembly 12 or wall of the container 10. A retaining ring 42 is provided adjacent the inner-most part of the cavity 40 (i.e., adjacent the interior of the container 10 where the gas is stored) to prevent the piston 20 from being pushed into the container 10. In addition, the cavity 40 is shaped so that it has a narrowed neck region 44 that receives the stem 28, so that the upper wall 26 of the piston 20 cannot extend into the neck region 44. In addition, the resilient element 30 abuts against the shoulder 46 of the neck region 44.
The operation of the pressure indicator system 14 is simple. If the container 14 contains gas, the pressure inside the container 10 will push the piston 20 upwardly (as viewed in the orientation of
If the container 10 has been emptied, or contains no more gas, then the natural bias of the resilient element 30 will push the piston 20 downwardly (as viewed in the orientation of
Instead of a piston, the embodiment of
The operation of the pressure indicator system 14a is similar to the system 14 of
If the container 10 has been emptied, or contains no more gas, then the natural bias of the resilient element 30a will push the stem 28a downwardly (as viewed in the orientation of
The pressure indicator systems 14, 14a of the present invention can be used for any pressure vessel or container (gas or liquid). They offer a number of benefits. First, the pressure indicator systems 14, 14a of the present invention are simple to use, and do not require secondary tools or equipment to determine if the container 10 is pressurized. Second, no special training is required for a user to use the present invention. Third, pressure indicator systems 14, 14a of the present invention provide a quick, easily-visible and simple warning to warn emergency personnel or any user that the container 10 is still pressurized.
While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.
