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:
May. 23, 2000
Filed:
May. 22, 1998
William J Friedman, Wooster, OH (US);
Edward McKiernan, Big Prairie, OH (US);
James A Sigler, Perrysville, OH (US);
Sealand Technology, Inc., Big Prairie, OH (US);
Abstract
A plastic sewage holding tank in a boat, associated with a toilet, includes a vent check valve assembly for providing vacuum relief. By mounting the vent check valve in the top of the tank, when the tank is being emptied by rapid pumpout implosion or other damage to the tank is prevented. The vent check valve assembly may include a valve body surface operatively connected to the tank and having a plurality of openings formed in it, and a flexible material diaphragm covering the openings adjacent the inside of the tank, and uncovering openings to allow air flow through the openings substantially only when a vacuum condition exists inside the tank. A plastic disk biases the diaphragm into its opening-covering position, but a partial vacuum of at least about 2-5 inches of water allows air to flow through the openings past the diaphragm.