RU2740327C1 - Pipeline gate - Google Patents

Abstract

FIELD: pipelines.SUBSTANCE: pipeline shutter comprises a body, a shutoff member, two seats, a shutoff member drive, a lubricant fluid between the shutoff member and seats, a lubricant supply union, a lubricating fluid injector, wherein the seat on the surface in contact with the shut-off member has an annular groove, a channel extending from the annular groove to the outer surface of the seat, the pipe-type gate includes a tube located inside the body of the gate, wherein saddle, tube, nozzle, injector are rigidly connected, and cavity, limited by shut-off element, annular groove, channel in seat, tube, nozzle and injector forms sealed closed space, filled with lubricating liquid with constant properties during operation, wherein tube design allows tube end adjacent to seat to freely move with seat, wherein forcing device creates pressure within 1.5–5.0 of process medium pressure in inlet branch pipe, and the tube is made of chrome-nickel stainless steel, which is well elastic and plastic deformation.EFFECT: invention provides tightness and multiple reduction of opening forces at whatever characteristics and directions of process medium.8 cl, 4 dwg

Description

FIELD OF TECHNOLOGY

The technical solution relates to the field of pipeline valves (gate valves, wedge, ball valves) and can be used in pipelines designed to shut off and control various liquid and gaseous flows, incl. and containing solid particles with pressures, preferably above 10 MPa.

In gates, opening or closing is carried out by moving the gate (gate, wedge or ball) relative to the seats pressed against it and ensuring tightness in the gate. The clamping force in the gate is created constructively due to the sealing block, which includes elastic elements. In the closed state, the process fluid pressure additionally presses the valve against the seat, increasing the clamping force and the frictional force in the valve. An increase in the friction force leads to an increase in the force required to open the shutter, gradual wear of the rubbing surfaces, leakage and failure of the shutter. With a bore size of more than 20 mm and a pressure drop on opposite sides of more than 10 MPa, such a force acts on the shut-off element of the gate that it is difficult or even impossible to open it due to high friction forces in the seal, leading to accelerated wear of rubbing surfaces or their breakage.

LEVEL OF TECHNOLOGY

Known designs and methods provide for the use in the seats of seals made of polymeric materials, for example, Teflon, which has a low coefficient of friction (about 0.05) relative to metallic materials. However, such seals at pressures above 10 MPa quickly lose their performance due to the low yield point, not exceeding 20 MPa, and material creep.

There are known methods where hard metal coatings, for example, chromium, nickel, etc. are applied to the rubbing surfaces of the shutter working bodies. and ceramics such as titanium, chromium or aluminum nitrides, etc. with subsequent polishing, providing some reduction in the coefficient of friction, which does not completely lead to the desired result.

Known gate valve [RU 2538993, 2015]. The gate consists of two outer and one inner wall, rigidly connected by pins. The inner wall has a window in which an unloading gate is located, which can be moved by the drive for a certain distance in the vertical direction inside the window and then carry the entire gate with it. The joints are sealed with Teflon plates. In the walls of the gate and the discharge gate there are discharge channels in the form of holes, which can both be combined and overlapped by the walls of these elements. When the gate valve is opened, the discharge gate rises upward by the amount of clearance, the holes are aligned with each other, as a result of which a discharge channel is formed, through which the process medium flows from the delivery side to the injection side of the gate valve, the inlet and outlet pressures are equalized, the forces on the gate drive decrease and the valve opens completely. The drive is equipped with discharge ports, with which the discharge gate has a movable contact with a tight fit.

The disadvantages of the device are the complexity of the design, the need for precision execution of all elements and the limitation of the pressure of the process medium due to the use of Teflon in the sealing plates, which has a low yield stress. In addition, such a valve can only operate in process media that do not contain solid particles, because the control channels are gradually clogged and do not ensure the reliability of the shutter.

Known ball valve [RU 2005243, 1993], in which a bypass channel with a valve departs from the inlet pipe, which is connected through the outlet saddle with the outlet pipe. Before turning the ball, open the valve and equalize the pressure between the inlet and outlet nozzles, reducing the forces on the actuator and the wear of the friction surfaces of the valve. Also known is a ball valve, in which the bypass channel is controlled by pressing the lever of the drive shaft [RU 2031294, 1995]. In the hole of the drive shaft there is a rod that controls the opening and closing of the valve and the communication of the inlet and outlet branch pipes of the valve. Before turning the ball, the drive shaft lever first presses the stem and only after bypassing the process and equalizing the pressure does it turn the ball to open the valve. The disadvantage of such ball valves is the unreliability of working with process fluids containing solid particles.

Known ball valves [SU 1639437, 1991; RU 17602224, 1992; RU 2011087, 1994], which also solves the problem of equalizing the pressure in the inlet and outlet nozzles using a very complex system of control and executive pneumatic and hydraulic drives, magnets, membranes, levers, spools, etc., which cannot provide reliable the operation of the shutter, especially in production conditions.

Known ball valves with a rising stem [companies CAMERON, https://www.products.slb.com/valves and CALVARY Valve, http://calvaryvalve.com], in which before turning the ball half-wedge shut-off body is removed from the seats, which provides low rod torque. The disadvantage of such gates is the rapid wear of the retraction and rotation mechanism of the ball valve and the loss of tightness due to high contact stresses. At pressures of the process medium of more than 10 MPa, such ball valves are inoperative due to increased wear and the risk of breakage of valve elements and joints.

Known slide gate, which contains a housing with inlet and outlet pipes and two seats with movable elements, between which there is a shut-off element in the form of a ball plug or gate, equipped with a drive for movement [RU 2355933, 2009]. The saddles are rigidly fixed in the body. The movable elements of the seats are arranged with the possibility of reciprocating movement along the longitudinal axis of the valve body and are equipped with annular cylinders, which are connected to the multiplier cylinders placed in the valve body, controlled by individual drives. The side wall of each annular cylinder is made in the form of two bellows of different diameters, located concentrically relative to the longitudinal axis of the valve body. The walls of each multiplier are made in the form of corrugated shells. The internal cavities of the annular cylinders and the corresponding multipliers are interconnected by a tube and form sealed cavities filled with a liquid that does not change its properties under operating conditions. The device allows you to control the pressing force of the seats against the shut-off element and ensure tightness in the shutter.

Shutter Disadvantages:

- the fundamental impossibility of a significant reduction in the friction force and wear in the valve due to the presence of the pressure of the process medium pressing the valve against the seat; an increase in the pressure of the process medium and the dimensions of the valve complicate the situation;

- an increase in the pressure of the process fluid requires an increase in the wall thickness, the rigidity of the bellows and shells, which also increases the pressing forces of the seats against the shut-off element and significantly complicates the design.

Known designs of pipeline gates, in which between the shut-off member and the seats is preliminarily placed or in the gap between them periodically during operation, a supercharger is supplied with a lubricating fluid that reduces the coefficient of friction and the force of opening the valve [for example, RU 2059137, 1996].

Disadvantages of such closures:

- squeezing out the lubricating fluid from the gap between the shut-off element and the seat into the valve cavity by pressing the shut-off element against the seat, created by the pressure of the process medium, low efficiency, especially at pressures of more than 10 MPa, due to the absence of a sealed enclosed space with sufficient rigidity;

- low pressures and difficulties in supplying the lubricating fluid by the blower before each opening of the shutter into the gap between the shut-off element and the seat.

DISCLOSURE OF THE INVENTION

The technical objective of the invention is a pipeline valve (slide, wedge or ball), devoid of the above disadvantages, ensuring tightness and multiple reduction of opening forces for any characteristics (pressure, composition, etc.) and directions of the process medium.

To solve the technical problem, a pipeline valve is proposed containing a body with inlet and outlet nozzles, a shut-off element (gate, wedge or ball), two seats adjacent to the shut-off element with through channels, the seats through elastic sealing rings contact the body, the shut-off valve drive, lubricating liquid between the shut-off element and the seats, a fitting for supplying lubricant liquid, a lubricant pump, characterized in that the seat on the surface in contact with the shut-off element has an annular groove, a channel extending from the annular groove to the outer surface of the seat, the pipeline shutter contains a tube , located inside the valve body, while the seat, tube, fitting, and blower are rigidly connected, and the cavity bounded by the shut-off element, an annular groove, a channel in the seat, a tube, a union and a blower forms a sealed closed space filled with a lubricating fluid with constant properties during operation , moreover, the design of the pipes ki allows the end face adjacent to the saddle to move freely with the saddle.

The depth of the annular groove is in the range of 0.05-1.0 mm.

The area of the annular groove adjacent to the shut-off element is determined by the formula Skk = (0.5-1.0) ⋅ (Spatr. ⋅ Pts) / Pszh [m ² ], where Spatr. - the area of the inner diameter of the branch pipe (the area on which the technological environment acts), m ² ; Ртс - pressure of the process medium, MPa; Рсж - lubricating fluid pressure, MPa.

The saddle has a second annular groove on the surface in contact with the shut-off element, made concentrically to the first one.

The shut-off body (gate, wedge or ball) and seats are made of infiltrated ceramic-metal material based on titanium carbide with bonds of nickel alloys or steels with a hardness of HRC in the range of 45-70 units according to patent RU 2525965 C2, 2014.

The supercharger provides pressure in the range of 1.5-5.0 of the pressure of the process medium in the inlet pipe.

A check valve is installed in front of the channel outlet into the annular groove.

The tube is made of chromium-nickel stainless steel, with a chromium content in the range of 9-20% and nickel in the range of 8-12%.

The tube is made in one layer.

The tube is made of multilayer.

The tube with the seat is permanently connected.

The tube with the seat and the union is detachably connected.

The connection between the blower and the union is bayonet.

The blower has a manual drive.

The blower is an integral part of the pipeline valve.

The second saddle of the pipeline valve is additionally equipped with a force reduction unit when changing the direction of the process fluid flow.

As a lubricant, oil heat carriers NeoSK-OIL170 with an operating temperature from (-80) to (+250) ° C or Termolan H200 with an operating temperature from (-20) to (+330) ° C or their analogues were used.

In open sources, information on the declared design of the pipeline valve (gate, wedge or ball) was not found.

DESCRIPTION OF DRAWINGS

The essence of the proposed technical solution is illustrated by the figures:

FIG. 1 - Slide gate scheme - option.

FIG. 2 - View A in Fig. 1 (enlarged).

FIG. 3 - Scheme of a ball valve - option.

FIG. 4 - View A in Fig. 3 (enlarged).

1 - Shut-off body (gate); 2 - Saddle; 3 - Annular groove; 4 - Tube; 5 - Fitting; 6 - lubricating fluid; 7 - Housing; 8 - Supercharger; 9 - Seal; 10 - Shutter drive; 11 - channel; 12 - Check valve; 13 - The first layer of the tube; 14 - the second layer of the tube; 15 - The second annular groove.

d is the average diameter of the annular groove; h is the depth of the annular groove; b is the width of the annular groove; δ - the amount of movement of the saddle and the end of the tube.

View B in Fig. 1 and FIG. 3 - additional unit for reducing the drive forces of the shut-off element.

CARRYING OUT THE INVENTION

The gate valve (Fig. 1) consists of a shut-off element (1), a seat (2) with an annular groove (3), a tube (4), a union (5), a lubricating fluid (6), a body (7), a blower (8 ), seals (9), valve drive (10). The saddle (figure 2) contains a channel (11) extending from the annular groove to the outer surface of the saddle.

A check valve (12) is installed in the seat channel, which prevents the lubricant from flowing out of the channel in the seat in the absence of pressure in the compressor (8), and a two-layer tube is rigidly connected to the channel outlet, which has an inner (13) and an outer layer (14). The inner and outer layers of the tube in the end zone are permanently connected, for example, by hard copper-silver solder. Lubricating fluid is constantly present inside the tube (6).

As a lubricant, you can use NeoSK-OIL170 heat transfer oils with an operating temperature from (-80) to (+250) ° С or Termolan H200 with an operating temperature from (-20) to (+330) ° С or their analogues.

The slide gate works as follows.

The flow of the process fluid moves, for example, from left to right (Fig. 1). In this case (with the exclusion of a slight influence of the viscosity of the lubricating fluid and the stiffness of the mating elements), the pressure of the process medium presses the shut-off element (1) against the right seat (2) with a clamping force equal to Ft = Pt ⋅ St, [MN],

where Pt is the pressure of the process medium, MPa;

St is the area of action of the technological medium on the shut-off element, m ² .

To open the slide gate, the drive of the gate valve is turned on and a certain force is applied to open the gate. After that, the lubricating fluid is injected into the cavity of the annular groove (3) through one or more movements of the hand pump handle (8) under pressure up to 300 MPa through the fitting (6), the tube (4) and the channel in the seat (11). This creates an opening force (Fo), which seeks to move the gate away from the seat, equal to Fo = Sкк ⋅ Рсж, where Sкк is the area of the annular groove (Sкк = b ⋅ 3.14 ⋅ d), Рсж is the pressure of the lubricating fluid. At the same time, the force of pressing the gate to the seat is overcome and a gap is formed between the gate and the seat, where a film of lubricating fluid penetrates and the coefficient of friction between them decreases, as well as the force required to drive the shut-off element, practically, up to 10 times. After that, the slide gate moves and the gate opens.

At the same time, in most cases, to significantly reduce the required efforts to open the pipeline valve, it is sufficient to pump a film of lubricating fluid not over the entire, but on a small area of the contact surface of the valve.

The second saddle of the pipeline valve can be additionally equipped with a unit for reducing the efforts of the drive of the shut-off member in the event that the flow direction of the process medium periodically changes to the opposite (Fig. 1, view "B", shown by dashed lines).

Lubricating fluid is only required to fill the annular groove in the seat and create an oil film between the elements each time the pipeline valve is opened. For example, for a valve with a nominal bore of 50 mm, the volume of the required lubricating fluid will be:

Vczh = Vp + Vk + Vpot. [cm ³ ], where

Vp is the volume of the required oil film, it is equal to the product of the contact area of the seat and the film thickness, i.e. = 28.26 cm ² (3.14 ⋅ 6 cm ⋅ 1.5 cm) ⋅ 0.01 cm = 0.2826 cm ³ .

Vk - volume of the channel in the saddle with a diameter of 0.3 cm and a length of 2.5 cm is: 3,14 ⋅ (0,3sm ^2/4) ⋅ 2,5 cm = 0.1766 cm ^3.

Vpot. - the volume of losses, which we will take equal to 100% of the sum Vп + Vк: (0.2826 + 0.1766) ⋅ 1 = 0.625.

Then the consumption of the lubricant for one cycle of opening the shutter:

Vczh = 0.2826 + 0.1766 + 0.625 = 1.25 cm ³ or approximately 1.25 ml.

For 1000 cycles of opening the pipeline valve, the lubricant consumption will be 1.25 ⋅ 1000 = 1.25 liters.

The minimum depth of the annular groove of 0.05 mm is selected based on the viscosity of widely used heat transfer oils at temperatures up to minus 40 and the possibility of their injection into the annular groove, and a depth of more than 1.0 mm is impractical, because requires an increased consumption of lubricant.

The area of the annular groove adjacent to the shut-off element is determined by the formula:

Sкк = k ⋅ (Spatr. ⋅ Рts) / Рсж [m ² ],

where k = 0.5-1.0 is a dimensionless coefficient taking into account the design features of the pipeline valve;

Spatr. - the area of the inner diameter of the nozzle, which is affected by the technological environment, m ² ;

Ртс - pressure of the process medium, MPa;

Рсж - lubricating fluid pressure, MPa.

For example, with DN = 50 mm, Spatr. = 3,14 ⋅ 0,05 ^2/4 = 0.00196 m ^2, Rtc = 100 MPa, p cortl p = 200MPa, SKK = (0,5-1,0) ⋅ (0,000196 ⋅ 100/200) = ( 0.5-1.0) ⋅ 0.000982 m ² or (0.5-1.0) ⋅ 9.82 cm ² .

With the coefficient k = 0.5, Skc = 0.5 ⋅ 9.82 cm ² = 4.91 cm ² .

With an average diameter of the annular groove of 60 mm, the width of the annular groove b = 2.6 mm.

In this case, a force is created to separate the right seat and gate, which is 50% of the force required for complete separation. Due to some asymmetry of the annular groove relative to the inner diameter of the nozzle, disconnection occurs only on one half of the seat.

With complete separation due to the creation of a continuous oil film, the coefficient of friction between the shut-off element and the seat and, accordingly, the forces on the drive, decrease approximately by 10 times, and with 50% disconnection, the decrease in the forces on the drive will be approximately 5 times ...

With the coefficient k = 1.0, the width of the annular groove is b = 5.2 mm.

In this case, the force required for complete separation over the entire surface of the right seat and gate is created.

It is recommended to add a second annular groove (15) concentrically to the first one (Fig. 2) to increase the reliability of the unit for reducing the drive forces. In the initial state, the pipeline valve is equipped with well-adjoining shut-off elements to ensure tightness and absence of leaks. At the same time, the drive force reduction unit operates with 100% efficiency. In the absence of solid abrasive particles in the technological environment, wear of the shut-off element elements due to friction is unlikely due to the presence of an oil film of the working fluid between them. In the presence of solid particles, wear of the elements of the shut-off element and leakage in the shutter may occur. In this case, the second annular groove becomes a "storage" of particles, drastically reducing wear and the likelihood of leakage. In addition, the presence of the second annular groove facilitates the process of grinding shutter elements to each other during manufacture and operation. An insignificant tightness in the valve will lead to the same decrease in the efficiency of the unit for reducing the drive forces, and with a significant loss of tightness, the use of a pipeline valve is lost.

It is recommended that the shut-off element (gate, wedge or ball) and the seats be made of infiltrated ceramic-metal material based on titanium carbide with bonds of nickel alloys or steels with a hardness of HRC in the range of 45-70 units according to patent RU 2525965 C2, 2014. a medium containing solid abrasive particles with dimensions of more than 0.1 mm and pressures of more than 10 MPa, as well as frequent “opening-closing” cycles of the gate, its intensive wear can occur with a significant loss of tightness and a decrease in the efficiency of the unit for reducing forces in the drive. The use of a high-hardness and wear-resistant material in the shut-off element can significantly reduce wear in the presence of a unit for reducing drive forces, and achieve a higher synergistic effect in terms of reliability, durability and resource. At a hardness less than 45 HRC, the effect is insignificant, and at a hardness of more than 70 HRC, the thermal shock resistance of cermet decreases, which limits the area of use of a pipeline valve.

It is recommended to select a blower that provides a working fluid pressure in the range of 1.5-5.0 of the process fluid pressure in the inlet. At pressures of the working fluid of 1.5 times the pressure of the process medium, the dimensions of the seat increase, and at pressures above 5.0, there is no practical need and the cost of the compressor unnecessarily increases.

It is recommended that a check valve be installed before the channel exits into the annular groove of the seat to prevent the lubricant from flowing out of the tube cavity when there is no compressor pressure in it and air enters the closed cavity. In addition, the check valve prevents the process medium from entering the cavity of the drive force reduction unit.

It is recommended that the tube be made of chromium-nickel stainless steel with a chromium content of 9-20%, nickel 8-12%, for example, grade 12X18H10T. Such steels lend themselves well to plastic deformation and can be used in chemically aggressive environments at temperatures up to 600 ° C when significant mechanical loads are applied.

It is recommended that the tube be made in a single layer with relatively small movements of the seat during operation.

It is recommended that the tube be made two-layer or multi-layer with increasing seat travel with a corresponding decrease in the thickness of each layer while maintaining the overall wall thickness. Reducing the thickness for the same tube length proportionally increases the range of displacement for elastic deformation, reliability and durability of the tube. In this case, the composite multilayer tube is made by tightly inserting one tube into the other, followed by brazing or welding the end portions to simultaneously bear the mechanical load caused by the pressure of the pumped lubricating fluid.

It is recommended to connect the tube with the saddle permanently, for example, by brazing to reduce the size of the connection area, provided that the valve can be installed. This increases the reliability of the connection, and the installation of the seat with the tube in the valve is simplified.

It is recommended to connect the tube with the saddle detachably, for example, on the thread for cases of need for disassembly, both to ensure the quality of the connected elements, and during operation. In this case, the dimensions of the connection zone increase slightly.

It is recommended that the connection of the blower to the union be made using a bayonet connection, since in this case, one and the same blower can be used for a group of pipeline valves due to the promptness of installation and dismantling.

It is recommended to use the blower with a manual drive to simplify the design, because a small amount of lubricant supplied by 1-2 movements of the blower handle is sufficient to separate the shut-off element and the seat. For example, a hand pump GHE-HP2800-1980 (for pressures up to 280 MPa), simplified and adapted for a pipeline valve, can serve as a blower. This eliminates the need for expensive mechanized injection devices.

It is recommended that the blower be made as an integral part of the pipeline valve, especially with its large dimensions, when the cost of the blower is insignificant relative to the cost of the valve.

It is recommended to additionally equip the second saddle of the pipeline valve with a unit for reducing the drive forces during periodic changes in the directions of the process medium. In this case, the left and right units of the reduction of efforts of the drive are included in the work as needed.

It is recommended to use heat transfer oil NeoSK-OIL170 with an operating temperature from (-80) to (+250) ° C or Termolan H200 with an operating temperature from (-20) to (+330) ° C, depending on the process temperature and environments or their analogues.

The offered brands of lubricant are available and not expensive.

As it is consumed, the lubricating fluid is subject to periodic replenishment.

The remoteness of the location of the friction force reduction unit from the process medium with a minimum consumption of lubricating fluid provides the ability to operate the valve at temperatures of the process medium up to 600 ° C and above.

FIG. 3 shows an embodiment of a ball valve equipped with a unit for reducing the efforts of the drive of the ball valve according to the claimed invention, and FIG. 4 - the same unit for reducing efforts in an enlarged form.

The presented figures show the well-known and proven by practice design of connections of the seat, tube, fittings and a blower for slide and ball valves, which ensure tightness at ultrahigh pressures up to 300 MPa. These figures provide a complete understanding of the design and eliminate the need for further detail.

Existing designs of slide, wedge and ball valves can be equipped with the declared units for reducing the drive forces with minor modifications and costs.

The effectiveness of the application of the declared pipeline valve grows with an increase in the dimensions and pressures of the process medium, because the cost of redesigning the design is reduced relative to the total cost of the shutter.

Thus, the claimed technical solution is novel and ensures the achievement of the set goal with the greatest efficiency.

Claims (9)

1. A pipeline valve containing a body with inlet and outlet nozzles, shut-off element, two seats adjacent to the shut-off element with bore channels, the seats contact the body through elastic sealing rings, the shut-off element drive, lubricant between the shut-off element and the seats, a fitting for supplying lubricating fluid, a lubricating fluid blower, with the seat on the surface, in contact with the shut-off body, has an annular groove, the channel extending from the annular groove to the outer surface of the seat, the pipeline shutter contains a tube located inside the valve body, while the seat, tube, fitting, blower are rigidly connected, and the cavity bounded by the shut-off body is annular a groove, a channel in the seat, a tube, a union and a blower forms a sealed closed space filled with a lubricating fluid with constant properties during operation, and the design of the tube allows the end of the tube adjacent to the seat to move freely with the seat, characterized in that the blower creates a pressure within 1.5-5.0 from ve the pressure of the process medium in the inlet pipe, and the tube is made of chromium-nickel stainless steel, which lends itself well to elastic and plastic deformation. 2. A pipeline valve according to claim 1, characterized in that the depth of the annular groove is in the range of 0.05-1.0 mm. 3. A pipeline valve according to claim 1, characterized in that the area of the annular groove adjacent to the shut-off member is determined by the formula Skk = (0.5-1.0) ⋅ (Spatr. ⋅ Pts) / Pszh [m ² ], where Spatr. - the area of the inner diameter of the inlet pipe (the area on which the technological medium acts), m ² ; Ртс - pressure of the process medium, MPa; Рсж - lubricating fluid pressure, MPa. 4. A pipeline valve according to claim 1, characterized in that the saddle has a second annular groove on the surface in contact with the shut-off member, made concentrically to the first one. 5. A pipeline valve according to claim 1, characterized in that the tube is made of chromium-nickel stainless steel, with a chromium content in the range of 9-20% and nickel in the range of 8-12%. 6. A pipeline valve according to claim 1, characterized in that a check valve is installed before the lubricant exits into the annular groove of the seat. 7. A pipeline valve according to claim 1, characterized in that the connection of the blower with the union is bayonet. 8. A pipeline valve according to claim 1, characterized in that the blower has a manual drive.

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