OVERFILL PREVENTING VALVE

摘要

An overfill preventing valve is adapted to be operatively interposed in a flow path between a fluid source and a compressed fluid storage cylinder to prevent the cylinder from being overly filled. The improved valve includes an el ongated tubular body having a first seat a first space a second space a second seat a third space a third seat a fourth space and an entrance portion communicating with a source. A passageway continuously communicate the first and fourth spaces. The second and fourth spaces communicate with the interior of the cylind er. A float is contained within the body for movement toward and away from the first s eat in response to the liquid level in the cylinder. A valve member is mounted on the b ody for sealed movement toward and away from the second seat. This valve member sepa rates the first space from the second space. The valve member is biased to move away f rom the second seat. A piston separating the third space from the fourth space, is mount ed for sealed sliding movement therealong toward and away from the third seat. The pist on is biased to move toward the third seat. The piston has a variable-area orifice com municating the entrance portion with the third space. The cross-sectional area of this orif ice varies as a function of the direction of the flow. When it is desired to fill the cylinder and the float does not engage the first seat, incoming fluid displaces the piston away from th e third seat and flows from the entrance portion into the cylinder via the fourth space. Howe ver, when the float sealingly engages the first seat, the valve member is caused to sealin gly engage the second seat, and the piston is caused to sealingly engage the third seat to prev ent further incoming flow from the source to the cylinder.