The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 18, 2008
Filed:
Jul. 15, 2005
Sadaki Nakano, Kokubunji, JP;
Koichi Yokosawa, Kokubunji, JP;
Yasushi Goto, Kokubunji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a hydrogen gas station where a great number of sensors are installed, in case hydrogen leakage occurs, sensors in the vicinity of the leakage location start to transmit a warning to an access point all at once. This causes channel capacity saturation and failure to transmit a warning to the access point. Nodes and the access point are connected to each other by an uplink channel and a downlink channel. The access point detects congested/uncongested status of the uplink channel by using a wireless transmitter module and notifies the nodes of the congested/uncongested status of the channel by means for transmitting onto the downlink channel. Meanwhile, each node controls its transmission operation, according to the hydrogen concentration level detected by its hydrogen sensor and the uplink channel congested/uncongested status notified from the access point. In this way, channel overflow due to access congestion in case of hydrogen leakage can be prevented.