US3036807A

US3036807A - Valve apparatus

Info

Publication number: US3036807A
Application number: US690836A
Authority: US
Inventors: Maurice C Lucky; Robert C Brooks
Original assignee: Cameron Iron Works Inc
Current assignee: Cooper Industries LLC
Priority date: 1957-10-17
Filing date: 1957-10-17
Publication date: 1962-05-29
Anticipated expiration: 1979-05-29

Description

May 29, 1962 M- c. LUCKY ET AL 3,036,807

VALVE APPARATUS I Filed Oct. 17, 1957 A D 3 Sheets-Sheet 1 Maur/c C. lac/(q Robe/f C. Brooks INVENTORS May 29, 1962 M. c. LUCKY ET AL 3,036,807

- VALVE APPARATUS Filed 001;. 17, 1957. s Sheets-Sheet 2 Maur/ce C LUCA y fPobe/v C. Brooks INVENTORS May 29, 1962 M. c. LUCKY ETAL I 3,036,807

VALVE APPARATUS Fild Oct. 1'7, 195? Y 3 Sheets-Sheet 3 Ai/VI/ Mau/vce C. Lucky 7 Robe/f C. Brae/rs INVENTORJ- 3,036,807 VALVE APPARATUS Maurice C. Lucky and Robert C. Brooks, Houston, Tex., assignors to Cameron Iron Works, linc., Houston, Tex. Filed Get. 17, 1957, Ser. No. 690,836 11 Claims. (Cl. 251-48) This invention relates to valve apparatus of the type in which line fluid assists in operating the closure member. More particularly, it relates to improvements in valve apparatus of the type in which line fluid is used as an assist in opening as well as closing the closure member.

It is conventional, in the case of blowout preventers disposable at the heads of petroleum wells, to admit well pressure to an area on the rear end of the rams which is greater than the area on the front end of the rams which is exposed to well pressure when the rams are closed. As a result, well pressure provides a force which assists the operators for the rams in maintaining them closed. However, this force, as well as that due to frictional engagement of each ram with the preventer body, must be overcome in opening the rams so that, when the well pressure is high, the power requirements of the operator are very large.

Although apparatus has heretofore been proposed for relieving as well as creating this force by the provision of means for selectively venting as well as admitting well pressure from and to the aforementioned area on the rear end of each ram, respectively, such apparatus has been complicated of construction and has required the manipulation of a large number of controls.

An object of this invention is to provide valve apparatus of this general type in which such power requirements for opening the closure member are materially lessened without the need for manipulating a large number of controls.

Still another object is to provide a valve apparatus of this general type which is especially well adapted for handling line fluids having solid particles therein, such as the mud commonly employed in the drilling of petroleum wells.

A further object is to provide such valve apparatus having a minimum of outside connections and inside connections which are short and direct.

These and other objects are accomplished by means of valve apparatus which comprises a body having a bore therethrough and an opening therein intersecting the bore. A closure member is movable within said opening to open and close said bore and an operator is provided for moving the closure member between opened and closed positions. In accordance with the present invention, a pressure chamber is for-med in part by a pressure responsive surface on the ram arranged to urge the ram closed upon the admission to the chamber of fluid from the bore of the body on one side of the closure member, and means are provided for automatically admitting such fluid to said-chamber, in response to actuation of the operator for closing the closure member, and venting said fluid from said chamber, in response to actuation of the operator for opening the closure member.

More particularly, the automatically operable means comprises passages connecting the pressure chamber with the bore of the body on one side of the closure member and a point removed from said one side, respectively, and valve means automatically operable, in response to the aforementioned actuation of the operator for closing the closure member, to open said first-named passage and close said other passage and, in response to the aforementioned actuation thereof for opening said closure member, to close said first-named passage and open said other passage. Thus, with the closure member in closed position and the first-named passage connecting with the bore on the upstream side thereof, high pressure line fluid will be admitted to the pressure chamber and act upon the pressure responsive surface of the closure member to provide a force which assists in maintaining it closed. On the other hand, when the operator is actuated to .open the closure member and line fluid is vented from said chamber, the force which the operator has to overcome is reduced and well pressure acting on the front end of the closure member provides an oppositely directed force which assists the operator in opening the closure member.

In the preferred form of the invention, the valve means is contained within the closure member, and the passages are formed within the closure member, so that the valve apparatus has no outside connections. Thus, the closure member is provided with a valve chamber, first and second conduits connecting the valve chamber with the bore of the body on the both sides of the closure member, respectively, and a third conduit connecting said valve chamber with the pressure chamber. The valve member is automatically movable, in response to actuation of the operator for closing the closure member, to a position connecting said first and third conduits and disconnecting said second and third conduits and, in response to actuation of the operator for opening the closure member, to a position connecting said second and third conduits and disconnecting said first and third conduits.

According to a still further preferred form of the invention, the aforementioned conduits connect with the sides of the valve chamber and the valve member is loosely received between said sides. More particularly, the second and third conduits connect with the same side of the valve chamber and the valve member is resiliently urged toward said one side. This construction is especially well adapted for the handling of line fluids containing solids and other gritty material, such as drilling mud, as it reduces the tendency of such fluids to clog the valve apparatus.

It is contemplated that the body of the closure member will be sealably slidable within its opening and that such opening will be closed so as to form the aforementioned pressure chamber at the rear end of the closure member.

In the drawings wherein like reference characters indicate like parts:

FIG. 1 is a longitudinal sectional view of one side of a blowout preventer constructed in accordance with the present invention;

FIG. 2 is a similar View of another embodiment of a blowout preventer constructed in accordance with the present invention;

FIG. 3 is a longitudinal sectional view of a gate valve constructed in accordance with this invention; and

FIGS. 4, 5 and 6 are longitudinal sectional views of a conduit type gate valve in its opened, and intermediate and its closed positions, respectively.

Referring now to the above described figures, the blowout preventer illustrated in FIG. 1 comprises a body It connectable at its opposite ends to suitable wellhead members and having a bore 11 therethrough. An opening 12 in the preventer body intersects the bore 11 at its inner end and is closed at its outer end 'by a cap 13. A ram 1'5 is disposed within the opening 12 for reciprocation between an open position (not shown) and a position (FIG. 1) closing the bore. As well known in the art, the preventer 1t} ordinarily will be provided with another ram facing oppositely to the ram of FIG. 1 such that, in the closed position of the preventer, the

inner ends of the rams will engage with one another and, when a pipe P is disposed within the well, about the pipe.

The body of the ram 15 is provided with seal means including a ring =16 about a portion intermediate its opposite ends and a packing 15' which extends across the inner end of the body and along the opposite sides thereof to connect with the ring 16. As shown in FIG. 1, the front packing 15 protrudes from the inner end of the ram body, so as to energize the packing and seal ring into sealing engagement about the pipe and with the opening 12 in the preventer body. Also, the packing 15 extends across only an intermediate portion of the inner end of the ram body to define a surface beneath it against which well fluid will act to urge the ram open.

The seal ring 16 forms a variable capacity pressure chamber 17 between the body of the ram and the cap 13, such that the rear end surface of the ram is responsive to pressure fluid contained within the chamber for urging the ram toward a closed position. As can be seen from FIG. 1, this surface is larger than that above-mentioned on the inner end of the ram body so that when both such surfaces are exposed to well fluid, the resulting force urges the ram closed.

Well fluid at high pressure is admitted to the pressure chamber 17 through a passage in the ram which includes a conduit 18 connecting the high pressure side of the packing on the ram with a valve chamber 19 within the ram body, and a conduit 21 connecting such valve chamber with the pressure chamber. The well pressure so admitted to the pressure chamber 17 is vented therefrom by means of a second passage which includes the conduit 21 and valve chamber '19 as well as another conduit 22 which connects the valve chamber with the inner end of the ram body on the low pressure side of the packing 15'. Obviously, this arrangement of the connecting passages entirely within the body of the ram 15 enables the line fluid to pass quickly from one location to another so that there is minimum opportunity for clogging the passages. Furthermore, with the passages disposed within the ram body, there is less danger of freezing and breakage which might otherwise occur with similar connections on the preventer body 10. Still further, if such a passage should become clogged or the mechanism to be described below should require replacement for any reason, it is only necessary to replace the ram itself.

The alternate admission and venting of line fluid is controlled by a valve member 23 mounted for longitudinal reciprocation within the valve chamber 19. This valve member 23 is provided with an opening 24 extending laterally therethrough so as to connect conduit 18 with conduit 21 when the valve member is in one position (FIG. 1), and a longitudinal slot 25 for connecting the conduit 21 with the conduit 22 in another position of the valve member (not shown). As can be seen from FIG. 1, when the valve member is in the first of these positions, it covers one end of conduit 22 so as to close the passage between the pressure chamber 17 and the low pressure side of the inner end of the ram. On the other hand, in the other of the valve member positions, the valve member 23 will prevent communication between conduit 18 and either of conduits 2/1 and 22 so as to disconnect the passage between said pressure chamber and the high pressure side of the inner end of the ram.

The operator for the ram comprises a stem 28 extending through the rear end of the ram body and mechanically connected at its inner end to the valve member 23 by means of a T-slot 29 or the like. This stem is reciprocable, in a manner to be described hereinafter, inwardly to move the ram to its closed position and outwardly to move the ram. to its open position. Thus, upon movement of the operator in a direction to close the ram, the inner end of the valve member will engage the inner end of the valve chamber so as to move the ram toward closed position. At the same time, conduit 18 is connected with conduit 21, so that when the ram reaches the closed position, well fluid will act upon the rear end of the ram to assist the operator in maintaining it in its closed position.

On the other hand, upon movement of the operator in a direction to open the ram, the rear end of the valve member will engage with the rear end of the valve chamber and the conduit 21 will be connected with conduit 22 so as to vent such well pressure to the bore 11 of the preventer body above the packing 15, which, of course, is an area of low pressure. Thus, the force urging the ram to closed position is relieved so that less power is required on the part of the operator in opening the ram. Also, as previously mentioned, the operator is assisted by a force due to well pressure acting on the inner end of the ram beneath the packing 15'. It is contemplated that this pressure responsive surface on the inner end of the ram will be of such size as to overcome the force due to frictional engagement between the upper side of the ram and the adjacent portion of the body opening 12 at the time the opening movement of the ram is initiated.

Viewing now the overall operation of the preventer, when the operator 2% is actuated to open the ram and the well pressure within chamber 17 is vented, the ram packing 15 will be pulled away from the pipe P due to one or both of the force of the operator and Well fluid acting on the inner end of the ram beneath such packing. The ram may move rearwardly at a faster rate than the valve member 23 to which the operating stem 28 is connected. in such a case, however, the conduit 21 would be covered by the valve member and thus slow up the movement of the ram body so as to return the valve member to its

position connecting conduits

21 and 22. Obviously, a similar situation prevails when the operator is actuated to close the ram. Thus, in the event of overtravel of the closure member, the valve member is automatically operable to prevent either the venting or the admission of fluid with respect to the pressure chamber during opening and closing movement of the closure member. It will also be understood that this process may be repeated during opening and closing of the ram such that the rate of movement of the ram body is maintained substantially the same as that of the valve member 23 and the operator.

From the foregoing, it will also be seen that when there is no differential pressure across the closed ram, it will be reciprocated solely by the operator. When such pressure differential is low, the above described admission and venting of line fluid will supplement the operator in reciprocating the ram. However, when such pressure diflerential is high, the operator merely reciprocates the valve member and the ram is reciprccated entirely by the pressure assists.

For the purposes previously described, the valve memer 23 fits loosely between the opposite sides of the valve chamber 19 and is urged toward the side of said chamber with which

conduits

21 and 22 connect by means of a leaf spring 26 or the like. Along this same line, it is contemplated that each of the chamber 19 and the valve member 23 may be rectangular. Furthermore, in the interest of minimizing the cutting effect of abrasives in the line fluid, the side of the chamber toward which the valve member is urged is provided with a wear plate 27 of very hard material, such as tungsten carbide. It will be understood that this surface is the one which will be the most subject to wear.

As previously described, the movement of the valve member 23, and thus the alternate admission and venting of line fluid with respect to the pressure chamber 17, is responsive to movement of the operator so that the ram is assisted in its opening and closing movements without the necessity of manipulating controls other than that for the operator.

As shown in the embodiment of FIG. 1, the stem 28 is sealably received through the cap 13 and provided with a piston 33 exteriorly of the cap for reciprocation within a motor cylinder 14 secured to the outer end of the cap by any suitable means. This construction provides a variable capacity pressure chamber on each side of the piston 33, both of which are connected to an hydraulic system 31 including a reservoir, a pump and a four-way valve 32, as shown in FIG. 1. In the position of the valve 32 shown in FIG. 1, hydraulic fluid from the reservoir is supplied under pressure to the rear side of the piston 33 so as to urge the operator in a direction for closing the ram. Upon reversal of the valve 32, the operator is retracted in a direction to open the ram. The outer end of the stem 28 may be sealably received within a boss on the cylinder 14, and the stem may be provided with a longitudinal port therethrough for venting the chamber within the boss. Obviously, other types of operators may be employed, if desired.

The embodiment of the blowout preventer shown in FIG. 2 corresponds in many respects to that above described in connection with FIG. 1. Thus, similar parts of the blowout preventer of FIG. 2 are designated by the same reference characters as the blowout preventer of FIG. 1, with the addition thereto of the letter a.

The principal difference between the blowout preventer of FIG. 1 and the blowout preventer of FIG. 2. lies in the construction of the valve member contained within the ram 15a for alternately admitting and venting well pressure to and from the pressure chamber 17a, as well as in the connection of the operator to the valve member for moving it between its alternate positions. Thus, as distinguished from the mechanical connection of FIG. 1, a valve member 34 and an operator comprising a reciprocating stem 28a are connected to one another by means of the fluid used in reciprocating the piston 33a of the operator within the motor cylinder 14a connected to body a of the preventer.

The valve member 34 comprises three longitudinally spaced apart discs 34a, 34b, and 340 which are sealably reciprocable within a cylindrical valve chamber 19a. The annular spaces surrounding the stem connecting the discs provide

passages

35 and 37 for connecting the conduits in the ram body in a manner to admit and vent well pressure to and from the chamber 17a. Thus, when the valve member 34 is retracted to the position of FIG. 2 wherein disc 34c engages the rear end of valve chamber 1%, the annular passage 35 connects conduits 21a and 22a so as to vent the Well fluid within pressure chamber ll7ato the inner end of the ram body above the packing a. When, on the other hand, the valve member 34 is moved forwardly, so that the disc 34w engages with the inner end of valve chamber 1%, the fiowway 37 will connect conduit 21a with conduit 18a so as to admit line fluid from beneath the packing on the inner end of the ram body to the pressure chamber 17a. In the first of these positions (FIG. 2), disc 3412 will seal off conduit 18a so as to disconnect the passage connecting the line fluid beneath the packing with the pressure chamber 17a. On the other hand, with the valve member in the other position (not shown), the disc 3412 will be disposed over and thus seal off the connection of conduit 22a with the Valve chamber 19a so as to disconnect the passage connecting the pressure chamber 17a with the bore of the preventer above the front packing.

As shown in FIG. 2, the operating stem 28a is provided with a first passageway 38 therethrough connecting the pressure chamber 39 on the rear side of piston 33a with the valve chamber 19a rearwardly of disc 340. Another passageway 41 is provided through the operating stem as well as the body of the ram 1501 so as to connect the pressure chamber 42 on the front side of the piston 33a with the portion 36 of the valve chamber in front of the disc 34a. Thus, pressure fluid supplied to the chamber 42 from an hydraulic system such as shown in FIG. 1 will be conducted through the passageway 41 to the portion 36 of the valve chamber so as to urge the valve member rearwardly to the position shown in FIG. 2 and thereby fluidly connect the operator to the valve member for moving the ram to its open position. This, in turn, will connect conduits 21a and 22a so as to vent the chamber 17a and thus assist the operator in opening the ram, in a manner previously described in connection with the blowout preventer of FIG. 1. It will be noted that while pressure fluid is admitted through the passageway 41, it will be exhausted from the valve chamber rearwardly of the disc 34c and returned to the hydraulic system through the passageway 33 and rear pressure chamber 39;

When it is desired to move the ram to closed position, pressure fluid is admitted to the chamber 39 to move the piston 33a and operating stem 28a forwardly and fluid is admitted to the valve chamber through passageway 41 to move disc 3441 into engagement With the inner end of valve chamber 1% and thereby fluidly connect the operator to the ram for moving the ram to such position. At the same time, conduit 18a is connected to conduit 21a so that when the ram moves into closed position, well pressure beneath the packing will be admitted to the chamber 1% to assist the operator in maintaining the ram closed. Of course, during such movement of the ram, pressure fluid within the portion 36 of valve chamber 19a is returned to the hydraulic system, through the a passageway 41 and chamber 42.

Additional characteristics of this embodiment of a lowout preventer will be obvious from the description of the PEG. 1 embodiment.

he gate valve shown in FIG. 3 includes a body 43 having a bore 44 therethrough and an opening 45 therein intersecting the bore. The opposite ends of the valve body 43 may be connected in any suitable manner within a flow line. A gate 45 is mounted within the opening 45 of the body for movement between an open position (FIG. 3) and a position (not shown) in which it closes the bore 44. As distinguished from the blowout preventers of FIGSv l and 2, this valve is provided with only one closure member or gate which is seatable in its closed position upon a side of the bore opposite the opening 45.

However, similarly to such earlier described blowout preventers, the gate 46 is provided with seal means which includes an annular ring 47 about a portion of its body intermediate the inner and outer ends thereof, and a packing 48 across an intermediate portion of the inner end of the gate body and extending along opposite sides thereof so as to cooperate with the seal ring in providing a continuous seal with the opening 45 in both the opened and closed positions of the gate. As shown in FIG. 3, the packing 48 is engageable with a raised portion 49 on the aforementioned opposite side of the bore of the body when moved into closed position.

The opening 45 in the valve body is closed by means of a cap 5% so as to form a pressure chamber 51 at the rear of the gate. This pressure chamber is connectable to the downstream, or low pressure, side of the packing on the inner end of the gate body by means of a passage made up of

conduits

52 and 53 in the gate body intersecting with a Valve chamber 54 therein. The pressure chamber 51 is connectable with the upstream, or high pressure, side of the packing on the inner end of the gate by means of another passage made up of the conduit 52, the valve chamber 54 and another conduit 55 formed in the gate body and intersecting with a side of the valve chamber opposite the side with which the

conduits

52 and 53 intersect. As shown in FIG. 3, the inner ends of the

conduits

53 and 55 are turned outwardly so as to intersect with opposite sides of the gate body close to the inner ends thereof.

Line fluid from the upstream, or high pressure, side of the packing 48 is alternately admitted to and vented from the pressure chamber 51 by means of a valve member 56 longitudinally reciprocal within the valve chamber 54 between a position (FIG. 3) opening the passage connect- 3,03e,so?

ing the pressure chamber and the downstream side of the packing and closing the other passage connecting the pressure chamber and the upstream side of the packing, and another position (not shown) opening said other passage and closing said first mentioned passage. More particularly, the valve member 56 is provided with a slot 57 on one side for connecting

conduits

52 and 53 while disconnecting

conduits

52 and 55 in said first position. In the second position of the valve member 56, its rear end will be moved forwardly of the intersection of conduit 52 with valve chamber 54 so as to connect the

conduits

52 and 55, and the solid portion of said valve member adjacent the rear end of the slot 57 therein will be disposed over the intersection of conduit 53 with the valve chamber 58 so as to disconnect

conduits

53 and 55.

The gate 46 will thus be found to be very similar in construction to the ram of the blowout preventer illustrated in FIG. 1. Along this same line, the valve member 56 is, similarly to the valve member 23 of the blowout preventer of FIG. 1, loosely received between the opposite sides of the valve chamber 54 and urged by means of a spring 58 toward the side of such chamber with which

conduits

52 and 53 intersect.

The operator for the gate includes a stem 59 which is connected at its inner end to the valve member 56 and extends through the rear end of the gate 46 and the cover 50 for movement inwardly to close the gate and outwardly to open same. Upon such inward movement of the stem, the inner end of valve member 56 abuts with the inner end of valve chamber 54 and conduit 55 is connected with conduit 52, in a manner previously described. As the gate is thus moved into a position abutting packing 48 with body portion 49, high pressure line fluid is admitted to the pressure chamber 51 for assisting the operator in maintaining the gate closed. On the other hand, as the operating stem 59 is moved outwardly, the rear end of valve member 56 abuts with the rear end of valve chamber 54 and conduit 53 is connected with conduit 52 so that the line fluid within pressure chamber 51 will be vented to the low pressure side of the packing 48. Thus, the force due to high pressure line fluid acting upon the surface of the inner end of the gate to the left (in FIG. 3) of the packing 48 assists the operator in opening the gate.

The conduit type gate valve shown in FIGS. 4 to 6 comprises a body 60 having a bore 61 therethrough and an opening 62 therein intersecting the bore. As in the case of the blowout preventer and the gate valve previously described, the opposite ends of the body 66 may be connected with a flow line in any suitable fashion. A gate 63 movea-ble within the opening 62 is provided with a conduit 64 therethrough for alignment in its open position (FIG. 4) with the bore 61 of the body. In the closed position of the gate 63, the conduit 64 is disposed within a well 65 formed in the valve body 60 opposite the opening 62 therein, and a solid portion of the gate is disposed across the bore 61.

Seal rings 67 and 68 are carried within the body opening and well respectively, to provide a sliding seal about the solid portion of the gate in both its open (FIG. 4) and closed (FIG. 6) positions as well as intermediate such position (FIG. With the end of the Well closed and a cover 66 disposed over the outer end of the opening 62, the seal ring 67 defines a pressure chamber 69 at one end of the gate and the seal ring 68 defines another such chamber 70 at the opposite end thereof. If desired, the seal rings may be carried by removable liners, as shown in FIGS. 4, 5 and 6.

The pressure chamber 69 is connectable to the downstream, or low pressure, side of the gate by means of a passage made up of

conduits

71 and 72 formed in the gate intermediate such pressure chamber and the conduit 64 and intersecting with a valve chamber 73. This same pressure chamber is also connectable with the upstream, or high pressure, side of the gate by means of another pas- 0 sage which includes conduit 74 as well as the conduit 71 and valve chamber 73. A valve member is longitudinally reciprocable within the valve chamber 73 between a position (FIG. 4) connecting

conduits

71 and 72 so as to open the first-named passage for venting pressure chamber 69, and disconnecting

conduits

71 and 74 so as to close the second-named passage, and another position (FIG. 6) connecting

conduits

71 and 74 so as to admit line fluid on the upstream, or high pressure, side of the gate to the pressure chamber 69, and disconnecting

conduits

71 and 72 so that the first-named passage is closed.

Additionally, the gate is provided with a conduit 80 which connects the valve chamber 73 with the pressure chamber 70 and is so arranged that, as the operator is actuated to close the gate, the conduit 80 will be connected to conduit 72 for venting the fluid within the chamber 70 to the low pressure side of the gate. This, of course, relieves any force which might otherwise prevent easy movement of the gate into closed position. On the other hand, as the operator is actuated to open the gate and the valve member moves into abutment with the rear end of the valve chamber, the conduits 7'4 and 84) are connected so as to admit high pressure fluid from the upstream side of the closed gate into the pressure chamber 70. The force thus applied to the end of the gate within chamber 70 assists the operator in opening the gate. In this respect, it will be noted that the surface of the valve body surrounding the conduit 61 on both sides of the gate may be slightly dished out, as shown at 81, to facilitate access of high pressure fluid into the

conduits

74 and 72.

For the purposes above described, the valve member 75 is provided with a first slot 76 for connecting conduit 72 with either conduit 71 or conduit 86 and a second slot 77 separated from the first slot and arranged to connect and disconnect

conduits

71 and 74. As in the case of the ram of the blowout preventer of FIG. 1 and the gate of the valve of FIG. 3, the valve member 75 is loosely received between opposite sides of the valve chamber 73 and urged by a spring 78 into engagement with the side of the valve chamber with which

conduits

71 and 72 intersect.

The operator for the gate 63 includes a stem 79 connected at its inner end to the valve member 75 and reciprocable within the end of the gate adjacent valve chamber 9 and the cover 66. Upon inward movement of the stem 79, the inner end of valve member 75 will abut with the inner end of valve chamber 73 and conduit 74 will be connected by slot 77 with conduit 71 and conduit '72 with conduit 89 by means of slot 76. As the gate is thus moved into its closed position, high pressure line fluid will be admitted to the pressure chamber 69 for assisting the operator in maintaining the gate in closed position, and fluid within chamber 70 will be vented to the low pressure side of the valve. On the other hand, upon outward movement of the operating stem, the rear end of the valve member 75 will abut with the rear end of valve chamber 73 to connect conduit 71 with conduit 72 through slot 76 and conduit 74 with conduit 86. Thus, as the operator is actuated to open the gate, the high pressure line fluid Within pressure chamber 69 will be vented to the low pressure side of the gate so as to relieve the force urging the gate closed and thereby lessen the power required of the operator in opening the gate.

When the bore is to be closed, the operator 79 is moved inwardly so as to bring the inner end of the valve member 75 into engagement with the inner end of the valve chamber 73, as shown in FIG. 6. In this manner, the gate 63 is moved toward closed position by the mechanical force of the operator as well as the force due to fluid pressure acting upon the surface of the gate within chamber 69. If this latter force is sufficient, without the assistance of the mechanical force provided by the operator 79, to overcome all frictional and fluid pressure forces which oppose closing movement of the gate, the gate will move at a faster rate than the operator and thus lead the valve member, as shown in FIG. 5. If allowed to persist, such a condition would tend to destroy the valve by impact. However, as indicated in FIG. 5, this overtravel of the gate relative to the valve member '73 will seal the fluid pressures within

chambers

69 and 70 so that the gate is slowed down until the valve member catches up with it. This cycle may be repeated several times, in accordance with well known servo principles, until closing is finally achieved, as shown in FIG. 6. Of course, a similar sequence may occur upon opening of the bore.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matters herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1s:

1. Valve apparatus, comprising a body having a bore therethrough and an opening therein intersecting the bore, a closure member moveable within said opening to open and close the bore, an operator for moving the closure member between opened and closed positions, a pressure chamber formed in part by a pressure responsive surface on the closure member arranged to urge it closed upon the admission to the pressure chamber of fluid from the bore on one side of the closure member, and means including a lost-motion connection between the operator and closure member and automatically operable, in response to actuation of the operator for closing the closure member, to admit said fluid to said chamber, in response to actuation of the operator for opening the closure member, to vent said fluid from said chamber, and, in response to overtravel of the closure member during opening and closing movement, to neither so vent nor admit said fluid.

2. Valve apparatus of the character defined in claim 1, wherein said automatically operable means includes valve means carried by said closure member and mechanically connected to said operator.

3. Valve apparatus of the character defined in claim 1, wherein said automatically operable means includes valve means carried by the closure member and fluidly connected to said operator.

4. Valve apparatus, comprising a body having a bore therethrough and an opening therein intersecting the bore, a closure member moveable within said opening to open and close the bore, an operator for moving the closure member between opened and closed position, a pressure chamber formed in part by a pressure responsive surface on the closure member arranged to urge it closed upon the admission to the pressure chamber of fluid from the bore on one side of the closure member, passages connecting the pressure chamber with the bore of the body on both sides of the closure member, respectively, and valve means providing a lost-motion connection between the operator and closure member and automatically operable, in response to actuation of the operator for closing the closure member, to open said first-named passage and close said other passage, in response to actuation of the operator for opening said closure member, to close said first-named passage and open said other passage, and, in response to overtravel of lb the closure member during its opening and closing movement, to neither so vent nor admit said fluid.

5. Valve apparatus of the character defined in claim 4, wherein said valve means is carried by said closure member and connected to said operator.

6. Valve apparatus, comprising a body having a bore therethrough and an opening therein intersecting the bore, a closure member sealably slidable within said opening to open and close the bore, an operator for moving the closure member between opened and closed positions, means closing the opening to provide a pressure chamber at the rear of the closure member, passages in the closure member connecting the bore of the body on opposite sides of said closure member with the pressure chamber, and valve means contained within said closure member providing a lost-motion connection between the closure member and operator and automatically operable, in response to actuation of the operator for closing the closure member, to open one of said passages and close said other passage, in response to actuation of the operator for opening the closure member, to close said one and open said other passage, and, in response to overtravel of the closure member during opening and closing movement, to neither so vent nor admit said fluid.

7. Valve apparatus, comprising a body having a bore therethrough and an opening therein intersecting the bore, a closure member moveable within said opening to open and close the bore, an operator for moving the closure member between opened and closed positions, a pressure chamber formed in part by a pressure responsive surface on the closure member arranged to urge it closed upon the admission of pressure fluid to said chamber, a valve chamber in the closure member, first and second conduits connecting the valve chamber with the bore of the body on opposite sides of the closure member, respectively, and a third conduit connecting said valve chamber with the pressure chamber, and a valve member within said chamber providing a lost-motion connection between the closure member and operator and automatically moveable to a position connecting said first and third conduits and disconnecting said second and third conduits, in response to actuation of the operator for closing the closure member, to a position connecting said second and third conduits and disconnecting said first and third conduits, in response to actuation of the operator for opening the closure member, and, in response to overtravel of the closure member during its opening and closing movement, to neither so vent nor admit said fluid.

8. Valve apparatus of the character defined in claim 7, wherein said conduits connect with the sides of the valve chamber and the valve member is loosely received between said sides.

9. Valve apparatus of the character defined in claim 8, wherein said second and third conduits connect with the same side of the valve chamber and said valve member is resiliently urged toward said one side.

10. A closure member for valve apparatus, comprising a body having seal means thereabout intermediate its opposite ends and across an intermediate portion of its inner end for extension along the opposite sides of the body to connect with the seal means thereabout, a valve chamber within the body, first and second conduits connecting the valve chamber with the inner end of the body on opposite sides of said seal means thereacross, respectively, and a third conduit connecting said valve chamber with the outer end of the body, a valve member reciprocable longitudinally within said valve chamber between a first position connecting said first and third conduits and disconnecting said second and third conduits, a second position connecting said second and third conduits and disconnecting said first and third conduits, and a third position disconnecting said third conduit with respect to both of said first and second conduits, and

1 '1 means for reciprocating said valve member between said positions, said valve member having oppositely facing surfaces thereon engageable With opposite ends of the valve chamber in the limits of its reciprocation.

11. A gate for a conduit type valve, comprising a body having a conduit extending laterally therethrough, a valve chamber Within the body, first and second conduits connecting the valve chamber with opposite sides of the body, third and fourth conduits connecting the valve chamber with opposite ends of the body, a valve member reciprocable longitudinally within said valve chamber between a position connecting said first with said third connection, and said second with said fourth connection, While disconnecting said first and third connections from said second and fourth connections, and another position connecting said first with said fourth connection and said second With said third connection, while disconnecting said first and fourth connections from said second and third connections, and means for reciprocating said valve member between said positions.

References Cited in the file of this patent UNITED STATES PATENTS 347,856 Wiedling Aug. 24, 1886 1,834,063 King Dec. 1, 1931 2,337,841 Shafer Dec. 28, 1943 2,690,192 Dannhardt Sept. 28, 1954 2,729,242 Olson Jan. 3, 1956 2,795,391 Krone June 11, 1957 2,828,767 Barusch Apr. 1, 1958 FOREIGN PATENTS 186,668 Great Britain Sept. 25, 1921