US3168282A - All metal valve with particular head and seat construction - Google Patents

Description

.1965 D. w. LATSHAW, JR ETAL 3,168,

ALL METAL VALVE WITH PARTICULAR HEAD AND SEAT CONSTRUCTION Filed Sept. 13, 1961 AAA mun:

rm 5 1 n INVENTOR. Donald W. Lafshavg-Tr: BY Russell E. Bosrwick .Afiorney United States Patent ()fiice 3,168,282 Patented Feb. 2, 1965 3,168,282 ALL METAL VALVE WITH PARTICULAR HEAD AND SEAT CONSTRUCTION Donald W. Latshaw, Jr., Los Altos, and Russell E. Bostwick, Mountain View, Calif, assiguors to Kane Engineering Laboratories, Palo Alto, Calif, a corporation of California Filed Sept. 13, 1961, Ser. No. 137,352 2 Claims. (Cl. 251333) This invention relates to an all metal valve construction and more particularly to an all metal valve construction for use in vacuum systems.

In copending application Serial No. 132,965, filed August 21, 1961, there is disclosed an all metal valve utilizing indium as a seating material. In the use of such a valve, it was found that it was difiicult to obtain the required reliability in such a valve because pipes or small passages occurred in the indium upon heating and cooling of the same which made it difiicult to obtain a reliable seal. In particular, it was found that these pipes or microscopic pass-ages were formed during initial manufacture of the valve when the valve was raised to a high temperature such as 1100 C. to obtain a wetting of the indium to the stainless steel walls forming the recess for the indium seating material. By actually heating the valve up to such an elevated temperature in a hydrogen furnace, the hydrogen reduces the oxide on the stainless steel to present a pure metal surface to the indium seating material so that a good bond is obtained between the indium and the stainless steel. However, after such a vacuum firing, it was found that these microscopic passages or pipes were formed in the indium seating material which made it difficult to obtain the proper type seal re quired. In addition to this problem, it was found that some times relatively large contraction cavities would be formed within the indium during cooling of the indium. For example, it was found that one cavity would form at the last spot to solidify in the seating material.

In addition, it was found that the knife edge configura tion utilized in the copending application Serial No. 132,-

provide an all metal valve construction which will over 7 come the above named difiiculties.

Another object of the invention is to provide an all metal valve construction of the above character which utilizes a seating material in which contraction cavities do not form and in which passages or pipes do not form.

Another object of the invention is to provide a valve construction of the above character having a valve member with a seat engaging surface of -a particular configuration to obtain a good sealing contact with the seating material.

Another object of the invention is to provide a valve construction of the above character having a particularly novel seating material.

Additional objects and features of the invention will appear from the following description in which the preferred embodiment is set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

FIGURE 1 is a cross-sectional view of an all metal valve incorporating our invention.

FIGURE 2 is an enlarged cross-sectional view of the seating material and the lower extremity of the valve member.

In general, our valve construction consists of a body having a passageway and inlet and outlet ports connected to the passageway. An annular recess is formed in the body and encircles the passageway. A relatively soft metallic seating material having a relatively low melting point is disposed in the recess. A valve member movable into and out of engagement with the seating material is utilized for closing the passageway. The valve member is provided with a depending annular flange which is formed with an annular knife edge-like portion which is adapted to engage the seating material. The knife edge-like portion is formed with concave surfaces on opposite sides of the annular knife edge-like portion extending away from the extremity of the knife edge portion to minimize pushing the seating material away from the extremity of the knife edge as it enters the seating material. A new and improved seating material is utilized and consists of an indium copper alloy in which contraction cavities and microscopic pipes or passageways are not formed.

As shown in the drawing, our valve consists of a valve body 11 which is formed to provide afluid passageway 12 and withports 13 and 14 connected to the passageway. The body of the valve is of a conventional T-type construction and is formed'of suitable material such as stainless steel. The body 11, as shown, is substantially cylindrical and is provided with atubular extension 16 which defines theport 14 and acap 18 provided with acylindrical extension 19 which defines theport 13. Anannular recess 21 is formed in thecap 18 as shown and is positioned in such a manner that the walls defining the inner side of the recess define a portion of the passageway. The inner wall of the recess is formed by an extension of thecylindrical member 19 which has its upper surface provided with an inwardly and upwardly extendingtaper 22 as shown.

Aseating material 23 is disposed within theannular recess 21. It is preferably an indium alloy. By way of example, we found that an alloy consisting of 5% copper and indium works very satisfactorily. However, we found that, if desired, a range of 1% to 10% of copper can be utilized with the remainder being indium.

Avalve member 24 is movable into and out of engagement with theseating material 23. As shown, the valve member is substantially cup-shaped and is provided with an annular depending flange 26 which has an annular knife edge-like portion 27 on its lower extremity. The

fannul-ar knife edge-like portion 27 has its outer and inner surfaces radiused to provide concave surfaces which extend upwardly from the lower extremity of the knife edge-like portion. This radiusing of the inner and outer walls of the valve member gives a somewhat tapered effect. The knife edge-like portion terminates in an annularflat surface 29 parallel to the upper surface of the seating material which is adapted to engage the seating material as shown particularly in FIGURE 2. It will be noted that the width of this annularflat surface 29 is relatively small and much less than the width of the upper surface of the seating material so that there is substantially a knife edge provided on the lower extremity of the valve member.

It has been found that this particudar configuration of the knife edge-like portion facilitates the obtaining of consistently good seals with the seating material. For example, in one embodiment of our invention, we have found that an annularflat surface 29 of 7 mils in width for a 1 inch valve operated very satisfactorily. The particular configuration of theradiused surfaces 28 provided on theportion 27 were also found helpful to obtain a better seal because they minimized the pushing aside of the seating material so that the surface. 29 always engaged a substantial amount of seating material.

Means is provided for moving thevalve member 24 between open and closed positions and consists of alead screw 31 threaded into a nut 32. The nut 32 is provided withtool recesses 33 and is affixed to acap 34 by suitable means such as welding Thecap 34 is afiixed to the body 11 of the valve also by suitable means such as welding; Astem 36 is formed on thetlower end of thelead screw 31 and is mounted within astem seat 37 which is' an integral part'of thevalve member 24. Awasher 38 is afiixed to the stem seat and engages agroove 39 provided in the stem to mount the valve member on the stem. Means is provided for establishing 'a vacuum-tight Seal between thevalve member 24 and the body and consists I of a bellows 41 which has its lower extremity in sealing engagement with the valve member 24and its upper extremity in sealing engagement with the side wall of the p a body 11 as shown. 1

Alead screw 31 is provided with asquared portion 42 which is adapted to be engaged by a suitable tool for rotating the lead screw as, for example, a knob '43 which has incorporated in it a conventional slip clutch such as the one built by the Snap-On Tool Corp. As is well known to those skilled in the art, such a knob is adjustable .so that upon the application of a predetermined amount of torque, the clutch built into the knob will slip to prevent additional tightening of thevalve member 24. As hereinafter described, this prevents running thevalve member 24 further down into the seating material than is required to establish a good vacuum seal.

Although other materials may be utilized, we have found it desirable to utilize stainless steel for all the parts of the valve except for theseating material 23.

Thecap 18 has such a configuration so that a heater 7 such as thatdescribed in copending application Serial No. 132,965, filed August 21, 1961, can be mounted on.

the cap to melt theseating material 23 to thereby reflow the seating material to remove any indentations which have been placed in the seating material by thevalve member 24. Thus, when the valve has been opened and closed a sufficient number of times so that the valve memwhich serves as a mechanical stop. The seating material should then be reflowed to provide a new seating surface in the valve. However, when this is accomplished, the valve seat should be in a horizontal position so that the seating material will not flow from therecess 21. As explained in the copending application Serial No. 132,965, filed August 21, 1961, this is advantageous because the valve need not be removed for this purpose.

It is apparent from the foregoing that we have provided a new and improved all metal valve with which it is pos sible to perform a large number of openings and closings of the valve while at the same time obtaining a good vacuum seal each time the valve is closed. The slip clutch provided controls the depth of penetration of the knife edge into the seating alloy so that a large number of closures can be obtained before the seating material must be reflowed. By way of example, We have found that unifom closing of the valves can be obtained which has a leakage conductance at the seat which is not more than 10* liters per second. The valve isconstucted in such a manner that the conductance of the valve can be easily and smoothly varied between maximum and minimum limits, The construction is such that the valve member can be moved to a-full open position to provide full porting and maximum conductance.

We claim:

1. In a valve construction, a body having a passageway and inlet and outlet ports connected to the passageway, an annular recess formedin the body, a relatively soft metallic seating material having a relatively low melting point disposed in the recess, said seating material being an alloy of indium and copper with the'copper ranging in percentage from one percent to 10 percent, and a valve member movable into and out of engagement with the seating material for opening and closing said passageway, the member having an annular depending flange formed with an annular knife edge-like portion on the lower extremity of the same adapted to engage the seating material, the knife edge-like portion being formed with only one annular surface lying in a plane substantially parallel to the plane of the seating material and adapted to engage the seating material, said knife edge-like portion also being formed with substantiallyconcave radiused surfaces on the opposite inner and outer sides of the annular knife edge-like portion and extending upwardly and outwardly away from said one annular surface ofthe knife edge-like portion, the configuration of the'knife edge-like portion being such as to minimize the pushing away of the seating material as the knife edge-like portion enters the seating material to thereby obtain a good seating engagement with the seating material. I V

2. In a valve construction, a body having a passageway and inlet and outlet ports connected to the passageway, an annular recess formed in the body, a relatively soft metallic seating material having a relatively low melting point disposed in the recess formed in the body, said seating material being formed of an alloy of indium and copper with the copper ranging in percentage from one percent to 10 percent, and a valve member movable into and out of engagement with the seat.

References Cited in the file of this patent UNITED STATES PATENTS 668,012 Locke Feb. 12, 1901 2,942,615 Dayton June 28, 1960 FOREIGN PATENTS 1,196,263 France May 25, 1959 849,253 Great Britain Sept. 21, 1960

Claims (1)

1. 2. IN A VALVE CONSTRUCTION, A BODY HAVING A PASSAGEWAY AND INLET AND OUTLET PORTS CONNECTED TO THE PASSAGEWAY, AN ANNULAR RECESS FORMED IN THE BODY, A RELATIVELY SOFT METALLIC SEATING MATERIAL HAVING A RELATIVELY LOW MELTING POINT DISPOSED IN THE RECESS FORMED IN THE BODY, SAID SEATING MATERIAL BEING FORMED OF AN ALLOY IN INDIUM AND COPPER WITH THE COPPER RANGING IN PERCENTAGE FROM ONE PERCENT TO 10 PERCENT, AND A VALVE MEMBER MOVABLE INTO AND OUT OF ENGAGEMENT WITH THE SEAT.

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