초록 ▼

A slow acting pneumatically operated valve which uses gas pressure and/or pneumatic pressure acting on a diaphragm to counteract the force of a coiled spring, thereby activating a double tapered fluorocarbon plastic poppet against a fluorocarbon plastic valve seat. Actuation of the poppet must be ex

A slow acting pneumatically operated valve which uses gas pressure and/or pneumatic pressure acting on a diaphragm to counteract the force of a coiled spring, thereby activating a double tapered fluorocarbon plastic poppet against a fluorocarbon plastic valve seat. Actuation of the poppet must be extremely slow and uniform such that fluid in the affected supply line does not experience shocks which can be transmitted to other supply line components. Actuation speed is restricted by use of a damping piston attached to the opposite end of the poppet stem, which restricts the flow of hydraulic fluid to opposite sides of the piston chamber during an actuation cycle. The double taper poppet incorporates an extremely low angle of incidence to the valve seat. Valve opening increases very slowly during the initial opening travel and decreases slowly during final closing travel, thereby further reducing the potential for fluid system shocks.

대표청구항 ▼

A slow-acting pneumatically operated fluid valve for semiconductor fabrication equipment, the valve being designed to minimize fluid supply system shocks that can dislodge particles within the supply system and contaminate components of the semiconductor fabrication equipment when the valve is opene

A slow-acting pneumatically operated fluid valve for semiconductor fabrication equipment, the valve being designed to minimize fluid supply system shocks that can dislodge particles within the supply system and contaminate components of the semiconductor fabrication equipment when the valve is opened or closed, comprising: a sealed axially aligned multi-part valve enclosure including a valve seat housing, an actuator housing a cylinder housing, and a cylinder end cap; an elongated valve stem movably mounted in the actuator housing of the valve enclosure for axial movement relative to it; a first sealed chamber formed within the actuator housing of the valve enclosure, the first sealed chamber being axially bounded by first and second diaphragms each having a rim sealed to the valve enclosure and a central section sealed and fixed to the valve stem at axially spaced positions along its length, the rim of the first diaphragm being sealingly disposed between the valve seat housing and the actuator housing and the rim of the second diaphragm being sealingly disposed between the actuator housing and the cylinder housing; fluid inlet means formed through the actuator housing of the valve enclosure in communication with the first sealed chamber for selectively directing fluid under pressure into the first sealed chamber to move the valve stem in a first axial direction relative to the valve enclosure; at least one biasing means within the actuator housing of the valve enclosure, the biasing means being operably connected between the valve enclosure and valve stem for urging the valve stem in an axial direction opposite to the first axial direction; a poppet at one axial end of the valve stem; a valve seat formed within the valve seat housing of the valve enclosure and axially facing the poppet, the valve seat being in fluid communication between first and second ports extending through the valve seat housing of the valve enclosure; a second sealed chamber formed in the cylinder housing of the valve enclosure, the second sealed chamber being bounded at one axial end by one of the first and second diaphragms; and the cylinder cap being fixed to the cylinder housing to close off the second sealed chamber; damping piston means fixed to the valve stem within the second sealed chamber inn the cylinder housing for restricting and controlling axial movement of the valve stem relative to the valve enclosure; whereby the actuation speed of the valve stem, in response to pressure of fluid directed into the first sealed chamber overcoming the biasing means, is slow and uniform throughout the entire movement of the valve stem.