Fluid handling – Processes – Cleaning – repairing – or assembling
Reexamination Certificate
2000-05-04
2002-07-30
Buiz, Michael Powell (Department: 3753)
Fluid handling
Processes
Cleaning, repairing, or assembling
C137S627500, C137S884000, C251S129150
Reexamination Certificate
active
06425409
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally as indicated to a valve and method of making such a valve and more particularly to a three-way valve in which a unitary bobbin/valve body provides the entire support structure for the solenoid and the plunger and defines all of the valve's inlet/outlet ports.
BACKGROUND OF THE INVENTION
A valve typically includes a plurality of ports through which fluid is selectively passed to accomplish a desired flow path. For example, a three-way valve may include a common port, a normally open port, and a normally closed port. When the valve is in an inactivated state, fluid enters the valve through the common port and exits through the normally open port. When the valve is in an activated state, fluid enters the valve through the common port and exits through the normally closed port.
A three-way valve may include a solenoid and a plunger that is used to shift the valve between its inactivated and activated states. Such a solenoid comprises components which generate and transmit a magnetic field. Specifically, a solenoid may include a solenoid coil which generates a magnetic field upon application of an electrical current and this magnetic field is transmitted to a pole piece. Terminal pins are typically provided to selectively energize the solenoid coil and a flux conductor is typically provided to concentrate magnetic flux in a desired manner.
A plunger commonly comprises a plunger body or armature which directs the flow through the valve in response to the energization/deenergization of the solenoid. A spring or other type of biasing assembly is typically provided to bias the plunger body towards a position whereat it seals off the passageway to the normally closed port and not the normally open port. When the solenoid is energized, the plunger body is pulled towards the pole piece by the magnetic force (that overcomes the spring biasing force) to a position whereat it seals off the passageway to the normally open port and not the normally closed port.
A three-way solenoid valve commonly includes a bobbin and one or more valve body pieces which together define the ports and which together provide a support structure for the solenoid and the plunger. The coupling of the bobbin and the valve body piece(s) together requires separate assembly steps and/or special coupling components. Moreover, the unions between the bobbin and the valve body piece(s) introduce leakage issues sometimes requiring separate inspection tests during assembly of the valve.
Three-way valves are used for a wide variety of industrial, medical, and other types of analytical systems. Different types of valve mounting arrangements are often required depending on the particular system. For example, some applications require a manifold mounted arrangement and other applications require a printed circuit board arrangement. Furthermore, different orientations of the valve ports are often required in different plumbing settings. Additionally or alternatively, it is often necessary (or at least desired) to have a two dimensional array of valves mounted on the same manifold and/or printed circuit board.
In many valve applications, dimensions are crucial and constant efforts are being made to reduce the size of valve assemblies. However, while size reduction is desirable, it often comes at the expense of more complicated assembly techniques and/or elevated manufacturing costs. Furthermore, the smallness of the bobbin and/or the valve body piece(s) tends to increase leakage issues during assembly due to, among other things, the tight tolerances involved. Additionally or alternatively, size reduction often results in the sacrifice of some desirable features, such as adjustability of valve seat sealing characteristics and/or electrical terminal options. Moreover, valve size reduction is sometimes difficult to accomplish within reasonable economic ranges and thus such reduction is of little benefit in many cost-sensitive valving situations.
Accordingly, the inventors appreciated that a need remains for compact and versatile valves that may be made by simplified assembly techniques and within reasonable economic ranges, without significant leakage issues.
SUMMARY OF INVENTION
The present invention provides a valve that may be manufactured and assembled in a relatively simplified and economic manner. Additionally, the valve's design is such that leakage issues are minimized and the valve may be used for a wide variety of industrial, medical and/or analytical systems without requiring different valve constructions. Further, a preferred form of the valve allows for adjustment of valve seat sealing characteristics (by changing the biasing force on the spring) and/or is compatible with different orientations of terminal pins. The valve may be produced in a very compact size thereby making it suitable for applications requiring small scale valving apparatus. However, the valve design of the present invention has many features equally advantageous in larger scale valving apparatus and thus the valve could be made in wide variety of dimensions.
More particularly, the present invention provides a valve comprising a bobbin/valve body, a solenoid, and a plunger. The bobbin/valve body is formed in one piece and defines a common port, a normally closed port, a normally open port, a longitudinal bore, and respective passageways between the longitudinal bore and the ports. The bobbin/valve body provides the entire support structure for the solenoid and the plunger whereby assembly and inspection steps associated with joining together separate bobbin and valve body piece(s) are eliminated. For this same reason, leakage issues may be significantly reduced. Additionally, the preferred bobbin/valve body may be made by economic mass manufacturing methods thereby further reducing manufacturing costs. Furthermore, a valve construction wherein a one-piece bobbin/valve body defines at least the normally open port (and not necessarily the common port or the normally closed port) is believed to in and of itself reduce the size of the valve.
The bobbin/valve body preferably comprises an end portion defining the normally open port, another end portion defining the common and normally closed ports, and a cylindrical central portion therebetween. The common port, the normally closed port, and the normally open port are preferably aligned with each other in the axial direction of the longitudinal bore thereby making the valve compatible with a variety of different mounting arrangements. For example, the valve is especially suitable for manifold mounting and to this end barbs are preferably provided on the port nipples to allow with-seal or without-seal coupling to the manifold channels. The valve is also especially suitable for mounting on a printed circuit board and to this end the exterior walls of the bobbin/valve body preferably include slots, grooves, and/or recesses to accommodate appropriate mounting elements (e.g., mounting wires, screws, clips, etc.).
The plunger includes a plunger body which moves within the longitudinal bore of the bobbin/valve body in response to the energization/deenergization of the solenoid. Specifically, the plunger body moves between a first position whereat the passageway to the normally closed port is sealed and the passageway to the normally open port is open and a second position whereat the passageway to the normally closed port is open and the passageway to the normally open port is sealed. In this manner, fluid flows through the common port to the normally open port when the plunger body is in the first position and through the common port to the normally closed port when the plunger body is in the second position. Preferably, the plunger body is moved to the second position upon energization of the solenoid.
The solenoid preferably includes a pole piece positioned within the longitudinal bore and the pole piece preferably defines a passageway from the bobbin/valve body's passageway to the normally open port. This passageway extends through an openin
Cross David P.
Farkas Andrew
Irwin Robert
Weiss Andreas A.
Buiz Michael Powell
Krishnamurthy Ramesh
Parker Hannifin Corp.
Renner , Otto, Boisselle & Sklar, LLP
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