Dead Weight Thief Hatch
OwnerRobert Carl Rajewskiinventor
Life of this patent
Estimating the term…
Abstract
A thief hatch has a pressure relief valve and vacuum relief valve. Each valve may use a weighted pallet with a diaphragm that sits in operation on a seat surrounding a throat. Pressure from the interior of the tank, for the pressure relief valve, or pressure from atmosphere, for the vacuum relief valve, presses the diaphragm against the seat. If the pressure rises too much, the pallet and diaphragm will lift off the seat to relieve pressure.
Claims20
A relief valve, comprising:
- a valve seat having a throat;
- a pallet constrained by guiding elements for movement towards and away from the valve seat;
- a diaphragm under the pallet, the diaphragm having a perimeter secured to the pallet and an interior bounded by the diaphragm and the pallet, the perimeter of the diaphragm being of greater two dimensional extent than the valve seat;
- the diaphragm being extended by a central extending element to form a conical or frusto-conical surface narrowing downward;
- and
- at least an opening in the diaphragm to allow fluid communication between the throat of the valve seat and the interior of the diaphragm, whereby in operation, pressure in the throat causes the diaphragm to bear against the valve seat.
A thief hatch is provided comprising a body having a portion configured for attaching the body to a tank, a valve seat supported by the body and the valve seat having a throat, a lid for the body, the lid having an underside, a pallet on the underside of the lid, the pallet being constrained by guiding elements of the lid for movement towards and away from the valve seat, a diaphragm under the pallet, the diaphragm having a perimeter secured to the pallet and an interior bounded by the diaphragm and the pallet, the perimeter of the diaphragm being of greater two dimensional extent than the valve seat, the diaphragm being extended by a central extending element to form a conical or frusto-conical surface narrowing downward, the lid being movable between a closed position in which the diaphragm contacts and rests on the valve seat and an open position in which the diaphragm is away from the valve seat, at least an opening in the diaphragm to allow fluid communication between the throat of the valve seat and the interior of the diaphragm, whereby in operation, when the lid is in the closed position, pressure in the throat causes the diaphragm to bear against the valve seat;
- and the lid in the open position permitting access to the throat.
Dependencies are inferred from the claim text.