Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including solid – extended surface – fluid contact reaction...
Reexamination Certificate
1999-04-19
2001-07-03
Tran, Hien (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including solid, extended surface, fluid contact reaction...
C422S177000, C429S057000, C429S082000, C429S086000, C429S089000
Reexamination Certificate
active
06254841
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to a recombination system for the catalytic recombination of hydrogen and oxygen, forming in storage batteries, into water.
BACKGROUND OF THE INVENTION
Recombination systems for electric accumulator or storage batteries have been pair of prior art for over 25 years. A system of that type is described in the DE-PS (German patent) 20088218. A corresponding catalyst is described in DE-PS 2213219, absorbers in DE 2237950 C3 and DE 2265701 C3.
To date, their basic design concept has remained essentially unchanged. The core feature of these recombiners is a catalyst-coated rod for instance of copper, alumina or the like. The catalysts most commonly used are platinum metals and especially palladium. The catalytic rod is centrally mounted in a tube of a porous material, for instance a gas-permeable ceramic tube; the remaining space in the tube is filled with absorption material. Absorbers employed include lead oxide, silver nitrate, iron oxide, cupric oxide and the like. The tube is enclosed in free-standing fashion in a gas-tight container preferably consisting of a synthetic material, and its ends are sealed. The container is provided with an adapter union by way of which it is connected to a storage battery for gas intake and water removal.
The hydrogen and oxygen gases which constitute an oxyhydrogen gas mixture and form during the operation of a battery are channeled into the container via the adapter union, pass by the porous tube and the absorbers and on contact with the catalyst are recombined into water. The reaction is exothennal so that the water precipitates in the form of water vapor on the container wall where it is condensed, and then flows back into the battery via the adapter.
In the publications mentioned, the container is in the form of a single unit directly incorporating the adapter, for example an injection-molded structure with an opening accepting, in gas-tight fashion, the catalytic unit described above. The oxyhydrogen gas cannot escape.
Prior art also includes configurations in which the connecting adapter and the container are produced separately and are assembled, by means of a retaining element, after the catalytic unit has been installed, whereupon they are locked together for instance by welding.
These earlier recombination systems have a number of drawbacks. While the individual elements, if plastic, are easy to make, their installation is complex and not automatable. In view of the exothermal reaction the entire, complex retaining element must consist of a high-quality, heat-resistant synthetic material. Separating the materials, as required nowadays, for disposal or even recycling of the individual components is possible at considerable cost only. In terms of its utilization, the size of the container is limited and the dimensions of the catalytic unit are tailored to a gas volume that is to be expected under normal operating conditions. However, in the event the gas volume is larger due to an overload, a higher charging current or the like, the container will fill up with water vapor, producing an internal pressure that prevents the intake of additional gas. Proper function of the unit is no longer assured. Yet any uncontrolled escape of oxyhydrogen gas must be avoided. It has also been found that any overload will substantially reduce the effectiveness of the catalytic unit since the oxyhydrogen gas entering the container no longer reaches the surface of the catalyst in reliable and controllable fashion.
Simply exhausting oxyhydrogen gas to the outside would pose an ignition hazard whereby the flame might propagate all the way into the battery.
Apart from the cost-related drawbacks in terms of production, assembly and disposal or recycling, the prime concern is inadequate safety in the event of an overload. Recombination systems are predominantly employed in conjunction with stand-by storage batteries, emergency-power units and the like and should ensure dependable operation, with a minimum of maintenance even over extended periods of time.
SUMMARY OF THE INVENTION
In light of the prior art referred to above, this invention is aimed at providing a recombination unit of the type described incorporating improvements which will prevent the hazards posed by escaping gas even under overload conditions. In addition, it is designed to prevent a deterioration of the efficacy of the catalytic unit in the event of an overload. As a whole, the intent is to allow for low-cost production, easy installation and maintenance-free operation of the system.
The technical solution proposed by the invention involves a recombination system incorporating an adapter union for the gas-tight connection of the system to a storage battery, a container that is gas-impermeable to the outside and houses a recombination assembly, and a conduit for the gas-tight intake of gas through the adapter into the container and for the water return flow in the opposite direction, with an expansion section provided next to the conduit which section is open toward but separated from the outside by an ignition suppressor, while the conduit connects to the expansion section by way of a gating aperture.
In the design according to this invention, gas will flow from the battery through the conduit and into the container in the process of which it is possible, if necessary, for gas to escape via the gating aperture into the expansion section situated next to the conduit and, if dictated by circumstances, to be exhausted through the ignition suppressor to the outside. The expansion section is preferably a short pipe extending laterally from the conduit. The conduit itself may be a tubular element, preferably funnel-shaped to facilitate water collection, attached to whose wall, at an essentially perpendicular angle relative to it, is a short pipe section. A suitable, recommended ignition suppressor is a sintered frit, for instance a frit of sintered polypropylene or polyethylene. The gating aperture is a bore in the wall of the conduit having a diameter substantially smaller than that of the conduit or that of the expansion section. In other words, the gating aperture is very small, for instance with a diameter of I mm whereas the diameter of the conduit or of the expansion section may be about 2 to 4 cm. Thus, under normal operating conditions, no gas will escape to the outside. If, however, an overload condition forces gas to the outside, the frit will prevent any break-through explosion. The ignition suppressor according to this invention constitutes a substantial improvement of the recombination system in terms of its safety aspects.
This invention offers another safety-related improvement addressing the possibility of ignition. Traditionally, a gas exhaust system is dimensioned in adaptation to a gas volume which in storage batteries is expected to be a function of capacity or of the charging current, so that in the event of an ignition the gases which have passed through the frit will burn off quickly. But if a larger volume of gas is generated, the flame will be continuously fueled. The flame will destroy the frit in short order, eliminating the ignition suppressor with well-known consequences, i.e. backfiring. For example, when a storage battery is designed for a charging current of 20A, the gas exhaust system will be designed to handle the gas volume to be expected. In terms of electronic capacity, modern storage batteries can easily be used or modified for operations involving or requiring higher charging currents. When higher charging currents are applied, or whenever a battery of essentially unchanged dimensions is to be designed for higher charging currents, the resulting gas volume will be substantially augmented and for the reasons stated the ignition suppressor can no longer be considered dependable. But the recombination unit should be protected against backfiring even under substantially greater than rated, expected gas volume conditions. This should be attainable without any basic design and size changes. According to another
Kesper Heinrich
Lahme Norbert
Vielhaber Ute
Accumulatorenwerke Hoppecke Carl Zoellner & Sohn GmbH & Co. KG
Cantor & Colburn LLP
Ridley Basia
Tran Hien
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