HK1095620B - Valve assembly - Google Patents

Description

Valve assembly

Reference to related applications

This application is a non-provisional application of U.S. provisional patent application serial No.60/481495, filed on 9/10/2003, the contents of which are incorporated herein by reference.

Technical Field

The present invention generally relates to fluid flow control valves.

Background

More and more flow control applications are going beyond the design of existing solenoid valves. These applications often involve pressure conditions that are not clear or vary during operation. For example, known solenoid valves may exhibit excessive internal leakage. Valve tuning is required to achieve better performance. Inconsistent turn-on voltages and control ranges are often required, and multiple orifice sizes are required to accommodate the range of working fluids.

The device of the present invention is intended to eliminate the drawbacks related to the prior art

Disclosure of Invention

According to the present invention, a valve assembly is provided that includes an orifice member defining a first surface. A plunger is movable relative to the orifice member, and a guide spring is disposed between the orifice member and the plunger. A portion of the guide spring is attached to the first end of the plunger such that the guide spring and the orifice member define coplanar surfaces that seal against each other to prevent fluid flow between the valve inlet and the valve outlet. A second guide spring, which may also be a flat spring, is attached to the opposite end of the plunger.

Drawings

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

FIG. 1 is a cross-sectional view of portions of a valve constructed in accordance with certain teachings of the present disclosure;

FIG. 2 is an assembled cross-sectional view showing those portions of the valve shown in detail in FIG. 1;

FIG. 3 illustrates a plunger assembly in accordance with the teachings of the present invention;

FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3; and

FIG. 5 is a cross-sectional view showing portions of a normally open valve in accordance with the teachings of the present invention.

Detailed Description

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Illustrative embodiments of the invention are now described. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. It will be appreciated, however, that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

FIG. 1 is a cross-sectional view of a valve 100 in accordance with the teachings of the present invention. The exemplary valve 100 is shown as a normally closed valve. The valve 100 includes a valve body 102 and a flow control portion 104. The valve body 102 defines a fluid inlet 106 and a fluid outlet 108. The fluid control portion 104 includes a valve plunger 110 that is movable relative to an orifice 112. A valve stem assembly 114 includes a retaining block portion 115 that surrounds the plunger 110 and orifice piece 112 and a pole piece 116 surrounded by a coil 118 to actuate the valve 100 as desired. The plunger 110 and valve stem assembly 114 are made of a soft magnetic material.

Fig. 2 shows portions of the flow control section 104 in detail. Valve plunger 110 has a first or lower guide spring 130 attached thereto, and the guide spring 130 is disposed between plunger 110 and orifice 112. The plunger 110, and therefore the first guide spring 130, moves relative to the orifice 112 to control fluid flow through the valve 100. The first guide spring 130 and the upper surface of the orifice 112 (as shown in fig. 1 and 2) adjacent the first guide spring 130 define surfaces that seal against each other when the valve 110 is closed.

Thus, the valve includes an overlapping surface of the orifice that seals against an overlapping surface of the pilot spring 130. When the valve retaining block portion 115 is pressed firmly against the valve body 102, the overlapping surface of the spring presses against the overlapping surface of the top of the orifice 112. Since these two surfaces lie in the same plane (coplanar), the spring 130 and the sealing area of the orifice 112 contact each other. This design feature yields several advantages. For example, two planar surfaces in contact with each other substantially eliminate any non-parallelism between the sealing surfaces. Two parallel overlapping surfaces in contact with each other produce very low leakage rate values. The overlapping sealing surfaces reduce deformation of the valve seat and orifice with controlled downward force during cycling of the valve open and closed. This reduces the occurrence of particles accompanying metal deformation.

In some embodiments, the first guide spring 130 is attached to the plunger 110 by two small range spot welds. To reduce the distortion of the overlapping spring surfaces during welding, two blind flat bottom openings 132 are etched into the guide spring 130. These openings 132 may be formed by etching the spring arms. The depth of the opening 132 varies depending on the thickness of the guide spring 130. This provides a thinner section through which to weld, reducing the amount of force required to effect the weld and, therefore, reducing the thermal effect zone around the weld.

A second or upper guide spring 140 is attached to the top surface of the plunger 110. In the illustrated embodiment, a flat spring 140 is welded to the top surface of the plunger 110. In the illustrated embodiment, the second guide spring 140 is stretched in a clamp to permanently deform the spring arm to a particular length. This ensures that the top surface of the second spring 140 contacts the adjacent surface of the pole piece 116 to form a frictionless support member. In the normally closed valve shown in fig. 1 and 2, spring 140 provides a small downward force toward plunger 110 to ensure shut-off at all valve installation locations. The spring 140 also ensures that the plunger 110 is radially supported, preventing radial movement of the plunger 110 when the plunger 110 is pulled toward the pole piece 116 during operation of the valve 100. The net result is to achieve a controlled/desired downward force that translates into greater consistency in the valve opening current. In another embodiment, a low spring constant helical compression spring is used in place of flat spring 140 to provide a preload force to plunger 110.

A nickel material sealing washer 144 provides a hermetic seal between the orifice 112 and the valve body 102 and also acts to increase the force holding the first spring 130 rigidly between the orifice 112 and the plunger 110. The nickel material sealing gasket 114 is advantageous in that it can deform unevenly around its circumference and thus accommodate any non-parallelism of the parts. In other embodiments, the sealing gasket 144 is made of other materials than nickel. For example, the sealing washer 144 may be made of fully annealed stainless steel for certain applications where the working fluid is not compatible with nickel. A second sealing gasket 145 of nickel material provides a hermetic seal between the retaining block 115 and the valve body 102, the sealing gasket 145 preventing the working fluid from leaking to the external environment. The sealing gasket 145 may be used in place of a corrosion resistant elastomeric material for applications involving working fluids incompatible with nickel.

The second guide spring 140 has a low spring constant that adds a preload force to the plunger 110. The length of the plunger 110 may be varied to control the air gap between the plunger 110 and the pole piece 116 according to the size of the orifice 112. The thickness of the lower guide spring 130 can be varied to optimize the control range of the valve. Typically, a smaller orifice will use a thicker lower guide spring 130 with a higher spring constant, while a larger orifice will use a thinner lower guide spring 130 with a lower spring constant.

The plunger 110 in the illustrated embodiment is short in length because it does not penetrate into the valve coil 118. This short length, in combination with the radial support provided by the upper guide spring 140, ensures that the plunger 110 does not move radially when the valve is operating in various installation conditions.

When the valve retaining block portion 115 is pressed firmly against the valve body 102, the internal components of the valve are clamped together. And therefore does not require internal threads. Internal threads are difficult to mechanically polish for ultra clean products. These internal threads may also produce particulate, moisture, and hydrocarbon contamination.

Fig. 3 and 4 illustrate another configuration for the plunger 110 and lower guide spring 130. The illustrated assembly uses a molded elastomeric insert 150 that is received in an opening 152 defined by the plunger 110. The insert 150 is retained in the opening 152 when the lower guide spring 130 is welded to the plunger 110. The excess rubber extending past the lower guide spring 130 becomes a bottom surface flush with the lower guide spring to provide a coplanar surface.

Fig. 5 shows portions of a normally open valve 101 in accordance with the teachings of the present invention. In the normally open valve 101, the plunger 110 is pulled toward the pole piece 116 when the coil 118 is energized. Without power, the lower guide spring 130 returns to its flat position. A spacer 160 is mounted between the lower guide spring 130 and the outer land of the orifice 112 to allow fluid flow therethrough during periods of no energization.

The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention.

Claims (9)

1. A valve assembly, comprising:

an orifice defining a first surface, the orifice having an inlet and an outlet;

a plunger movable relative to the orifice member;

a first guide spring located between the orifice and the plunger with a portion of the first guide spring attached to a first end of the plunger, the first guide spring defining a second surface that is directly sealable against the first surface to prevent fluid flow between the inlet and the outlet, and wherein two blind flat bottom openings are etched in the first guide spring to reduce deformation of the overlapping surfaces of the first guide spring during attachment of the first guide spring to the plunger.

2. The valve assembly of claim 1, wherein said first guide spring is attached to said first end of said plunger by spot welding.

3. The valve assembly of claim 1, further comprising a second guide spring attached to the second end of the plunger.

4. The valve assembly of claim 1, further comprising:

a valve body; and

a seal between the orifice and the valve body.

5. The valve assembly of claim 4, wherein the seal comprises a gasket of nickel material.

6. The valve assembly of claim 1, further comprising an elastomeric insert received in an opening defined by the plunger.

7. The valve assembly of claim 1, wherein the valve is a normally closed valve.

8. The valve assembly of claim 1, wherein the valve is a normally open valve.

9. The valve assembly of claim 3, wherein the second pilot spring comprises a flat spring.