EP0221896A1

EP0221896A1 - Metallized valve

Info

Publication number: EP0221896A1
Application number: EP85902840A
Authority: EP
Inventors: Richard E. Howard; John C. Schumacher
Original assignee: JC Schumacher Co
Current assignee: JC Schumacher Co
Priority date: 1985-05-17
Filing date: 1985-05-17
Publication date: 1987-05-20
Also published as: WO1986006811A1; FI870180A0; DK24387A; NO870193L; DK24387D0; JPS62503047A

Abstract

Soupape métallisée construite et composée de manière à faciliter la manipulation de produits chimiques de grande pureté et qui réagissent avec l'humidité ou l'oxygène ou dont l'efficacité est limitée par l'humidité ou l'oxygène.Metalized valve constructed and composed to facilitate the handling of chemicals of high purity and which react with humidity or oxygen or whose effectiveness is limited by humidity or oxygen.

Description

METALIZED VALVE Field of the Invention

This invention relates to valves generally, and, particularly, to valves for handling high-purity reagents. Background of the Invention

Valves are not usually considered to be sources of contamination. Indeed, in most systems, the valve, by the very nature of its construction, having a heavy body as compared with the thickness of the walls of pipe, conduit, or tubing connected thereto, is not considered to be permeable to any contaminant. Sometimes, valve seals are imperfect and, therefore, constitute a source of contamination, but the body of the valve per se is not considered to be such as would permit entry of any contaminants.

In the handling of certain ultra high-purity reagents, providing a valve which is chemically inert to the reagent, and also impermeable to oxygen and moisture, presents a serious problem. In. he past, this problem has simply been tolerated with a decrease in quality, or, systems have been encased in totally inert atmospheres. One such art in which this problem is a very important limitation is in the field of the manufacture of certain electronic devices, and certain optical devices. Reference will be made here to the manufacture of semiconductor devices, but the same principles apply wherever ultra high-purity chemicals which are reactive with oxygen or moisture are handled.

Many chemicals are reactive with most metals. Noble metals may be used in many instances, but the cost of such metals precludes their effective use in all but extremely rare instances. There are many polymers which are known to be inert, or relatively inert to most chemicals. Differing polymers have a differing level of inertness, of course, but generally speaking, the organic polymers are less reactive with most chemicals reagents than are metal. It is, therefore, common practice to provide valves, conduits and other elements formed of various polymeric materials. The use of such materials solves many problems and provides a great convenience. However, in certain instances the use of such materials has been discovered to create a serious source of contamination. Thus, while most of these polymeric materials are considered to be vapor impermeable, they nevertheless permit minute amounts of oxygen and moisture, along with other gases, to permeate through the walls of the valve. Such valves are, therefore, not suitable for certain long-term storage and certain handling applications in which ultra high-purity, highly reactive chemical reagents are stored or handled. This invention is directed to a solution to this problem in which the benefits of the inertness of the organic polymer are retained, and the disadvantage of gas and moisture permeability is eliminated.

Summary of the Invention The present invention comprises a valve especially constructed and composed to facilitate the handling of high-purity chemicals which react with, or whose effectivenss is limited by moisture or oxygen, thus resulting in contamination of the chemical. The valve body is composed of a polymer which is inert to the chemical to be handled by the valve. The body is so constructed that it forms an inlet and an outlet, and a passage for valving means. The valve body is coated with a layer of oxygen and moisture vapor impermeable metal bound to the external surface of the body, forming a coherent, cohesive gas and moisture barrier on the body of the valve. Means are provided for connecting inlet and outlet conduits to the valve, and valving means is movably received in the passage for being moved from an open to a closed position where, respectively, fluid is permitted to flow from the- inlet to the outlet, or such fluid flow is closed off. In a preferred embodiment, the valve also has operability associated with, or carried on with a valving member, and a puncturing means for puncturing a seal on the end of the conduit. The invention, in one facet, comprises a combination of conduit, a seal closing the end of the conduit, and a valve body composed of polymer which is inert to the chemical to be handled by the valve. The body is so constructed as to form an inlet and an outlet, and a passage for receiving the valving means. The entire body is coated with a layer of oxygen and moisture vapor impermeable metal which is bound to the external surface of the valve body, providing a complete or substantially complete barrier to any permeability of any gas or moisture. These are provided for connecting the valve body to the conduit, and valving means are movably positioned in the passage for being moved from an open position and a closed position, thereby permitting or closing off fluid communication between the inlet and the outlet. The valve includes seal puncturing means operably associated with^' a valving member for breaking the seal on the conduit when the valving member is moved in a predetermined way. Typically, the valving member moves reciprocally in a passage in the valve body, and the puncturing means is carried on one end of the valving member. When the valving member is closed, the puncturing means breaks or opens the seal over the end of the conduit, and, upon moving the valve to the open position, a fluid flow path is established between the inlet and the outlet through the valve body, all the while the fluid being protected from contamination by gas or moisture vapor by the gas impermeable layer of metal on the outside of the valve body. In a particularly preferred embodiment, the entire body, or at least the internal parts of the body, are fluorinated to decrease the chemical reactivity thereof, after the body is formed. Brief Description of the Drawings Figure 1 is a side view, in cutaway, -showing the construction of the valve according to this invention connected to two conduits.

Figure 2 is a side view and partial cutaway showing the combination of this invention as it may be used as part of an article of commerce.

Figure 3 is an enlarged cross-sectional view of a portion of the valve body taken at the intersection of the outlet with the valve body in Figure 2, showing the metal coating over the threads, as well as the main part of the valve body.

Brief Description of the Preferred Embodiment

In one form, the preferred embodiment of the invention is a valve which is especially adapted, constructed, and composed to facilitate the handling of high-purity chemicals which react with moisture or oxygen, and, by such reaction become contaminated. The valve 10 of this invention is best shown in Figure 1 to which reference is now made. The valve 10 comprises a body 12 which is composed of a polymer which is inert to the chemical to be handled by the valve, the body forming an inlet 14 and- an outlet 16. The valve body is composed of a polymer. A great many organic polymer≤ may be used. Polyethylene, nylon, polyvinylfluoride, etc., may be used, depending upon .the particular reagent to be handled. High density linear polyetheylene, polyetheylene terphthalate, and polyvinylidine chloride are preferred, although the invention is not limited to the use of these particular polymers. The valve body also forms the passage 18 for receiving valving means 20.

Means are provided for connecting the inlet of the valve to a conduit 100. . In the particular form shown in the exemplary embodiment, the conduit 100 is of glass or quartz, and has a groove 102 formed therein into which a keeper washer 22, which -is sufficiently resilient to slip over the end of the conduit, is received. A conical ferrule 24 is held in compression by a nut 26 which secures the conduit in place. It will be noted that the conduit 100 is closed by a seal 104 which may be a noble or other inert metal disc, or a frangible quartz or glass seal.

The seal butts against the shoulder 28 formed at the juncture of the passage and the inlet in the valve body.

The outlet conduit 106, which may also be of quartz or glass, is held in place in a similar manner, in this instance simply using a conical ferrule 30 and a nut

32 holding the outlet conduit in compression in the outlet of the valve.

The valving means 20 comprises, in the embodiment illustrated, which is merely exemplary, an elongate ^• shaft generally indicated at 34, and a handle generally indicated at 32, the shaft 34 being threaded and being shown at 38, and being threadably received for reciprocal movement in corresponding threads inside the passage of the valve body, the passage being shown at 18. In the particular example shown in Figure 1, the valving means includes a notch 40 into which an "0" ring or other sealing device 42 is received. In compression between the valving means and the wall of the passage in the valve body, a gas tight seal is formed therebetween. In the preferred embodiment, a means for breaking the seal, shown at 42, is attached to, or carried- on, or otherwise operably associated with the valving means. As will be seen in Figure 1, as the valving means is moved downwardly, thus closing the valve off and closing the passage which would otherwise permit fluid communication between the inlet and the outlet, the breaking means punctures the seal 104. When the valving means is moved upwardly, opening it to fluid communication between the inlet and the outlet, then the fluid is permitted to flow from the inlet^' to the outlet, thus permitting fluid communication between the conduit 100 and the conduit 106. The valving means is secured in a gas tight relationship with the passage of the valve body by ferrule 46 and the nut 48. It will be understood that this is simply an exemplary form of the valve, and many, many forms of the valve may be utilized without departing from the principles of this invention. To the extent heretofore described, the valve would function quite satisfactorily from the point of view of simply breaking the seal, opening and closing the passage to fluid flow. However, the problems which have plagued the industry for at least two decades would remain, namely that as the reagent flowed from the conduit 100 through the valve, and out the conduit 106, it would be contaminated with oxygen, moisture, or some other gas which permeated through the body of the valve. To cure ' this problem, a layer 50 of metal is formed over the outside of the valve body. The layer 50 may cover only the major portions of the valve body, since there is a diminished problem of gas permeation around the inlet and the outlet. However, as best shown in Figure 3, the metal area may also encompass the threads on the valve.

The metal may be any of a large number of inert, or relatively inert metals. The metal may, for example, be stainless steel, chromium, zinc, cadmium, tantalum, or the noble metals, although cost usually precludes use of the noble metals. The layer of metal may be formed by electrolytic coating, with appropriate pre-treatment and a molecular thin layer of copper, by sputtering or vapor deposition. The layer of metal is typically from 0.003 to 0.010 in thickness, and preferably around 0.006 of an inch in thickness.

The embodiment shown in Figure 2 is identical to that in Figure 1 with the exception that- this combination is a part of an article of manufacture which may be shipped. In this instance, the valve is secured, as part of the article of manufacture, and shipped in commerce, and the outlet is simply closed with a plug 108. Otherwise, the valve is identical as described before. This combination is particularly useful since the valve is already in place, and it is simply necessary for the recipient to remove the nut 32 and the plug 108, and replace the plug 108 with a suitable conduit going to the system to which the reagent is to be directed for use. Υh valve is, of course, shipped in the open position. Once it is connected to the system for use, and purged or evacuated, then the valving member is moved downward breaking the seal, not shown in Figure 2 but shown in Figure 1, Figure 2 being identical in this respect, thus 5 permitting fluid to flow from the conduit which forms part of the combination through the inlet, the valving passage, and of the valve at the outlet.

It is to be emphasized that this is a convenient kind of valve, but many kinds of valves, in many shapes ₁0 and configurations, could be made which would be in substance the same. Thus, the particular configuration of this valve is merely exemplary. Thus, these and other modifications may be made without departing from the spirit or the scope of the invention, or from the 15 following Claims which includes a reasonable scope of equivalence.

Industrial Application This invention finds application in the electronics, optics and semiconductor industry for the 20 storage, shipping and handling of ultra high-purity reagents.

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Claims

CLAIMSWHAT IS CLAIMED 1ST

1. A valve especially constructed and composed to facilitate the handling of high-purity chemicals which react with moisture or oxygen, comprising: a valve body composed of polymer which is inert to the chemical to be handled by the valve, the body forming an inlet and an outlet, and a passage for receiving a valving means; a layer of oxygen and moisture vapor impermeable metal bound to the external surface of the valve body; means for connecting inlet and outlet conduits to the valve body; and valving means movably received in the passage for being moved from an open position to a closed position for, respectively, permitting fluid communication between the inlet and the outlet, and closing off such fluid communication.

2. The valve of Claim 1 further comprising seal puncturing means on the valving member.

3. The valve of Claim 2 wherein the valve body __is composed of polyetheylene terphthalate or polyvinyli- dine chloride.

4. The valve of Claim 3 wherein the metal layer is chromium.

5. The valve of Claim 1 wherein the valve body is fluorinated after the passage and- inlet and outlet are formed.

6. The valve of Claim 1 wherein the valve body is composed of polyetheylene terphthalate or polyvinyli- dine chloride.

7. The valve of Claim 1 wherein the metal layer is chromium.

8. The valve of Claim 1 wherein the valve body is fluorinated after the passage and inlet and outlet are formed.

9. In combination, a conduit, a seal closing the end of the conduit, a valve body composed of polymer which is inert to the chemical to be handled by the valve, the body forming an inlet and an outlet, and a passage for receiving a valving means, a layer of oxygen and moisture vapor impermeable metal bound to the external surface of the valve body, means connecting the valve body to the conduit, valving means movably received in the passage for being moved from an open position to a closed position for, respectively, permitting fluid communication between the inlet and the outlet, and closing off such fluid communication, and seal puncturing means operably associated with the valving member for breaking the seal on the conduit by moving the valving member.

10. The combination of Claim 9 wherein the valve body is composed of polyetheylene terphthalate or polyvinylidine chloride.

11. The combination of Claim 9 wherein the metal layer is chromium.

12. The combination of Claim 9 wherein the valve body is fluorinated after the passage and inlet and outlet are formed.