Patent ID: 12215797

Description of parts is as follows:

1is left connecting pipe;2is left nut;3is left sealing gasket;4is valve seat gland;5is valve seat;6is valve stem;7is ball core;8is valve body;9is right nut;10is right sealing gasket;11is right connecting pipe;13is pipeline; and14is through hole.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following examples are intended to illustrate the present invention, but are not intended to limit the scope of the present invention.

Referring toFIGS.1,2A-2B, and3-4, the present invention provides an internally-sealed one-piece external thread ball valve, in which the ball core7is connected with the pipelines13by welding type loose joints without reducing the diameter. The valve seat gland4and the left sealing gasket3thereout enter the valve body8, and the left sealing gasket3is an inverted trapezoidal ring. The specific structure is described as follows.

The internally-sealed one-piece external thread ball valve includes connecting pipes, a left sealing gasket3, a valve seat gland4, nuts2and a valve body8, wherein the left sealing gasket3is arranged in the valve body8, the contact part of the valve body8and the valve seat gland4is an internal thread, the contact part of the valve body8and the left sealing gasket3is a smooth inner circular surface, the left sealing gasket3is an inverted trapezoidal ring, the left sealing gasket3expands outwards under an action of pressure formed by tightening the nuts2during valve assembly, and the outer circular surface of the left sealing gasket3and the inner circular surface of the valve body8form sealing.

In some embodiments, the internally-sealed one-piece external thread ball valve further includes the pipelines13, the connecting pipes and the ball core7, wherein the valve is in movable connection with the pipelines13, outer walls of two ends of the valve body8are threads, loose joint parts connected with the two ends of the valve body8include the left sealing gasket3, the connecting pipes and the nuts, the left sealing gasket is made of a non-rubber plastic material, a through hole14is formed in the ball core7, and a diameter of the through hole14is equal to an inner diameter of the pipelines13. Specifically, the connecting pipes include a left connecting pipe1and a right connecting pipe11, wherein the left connecting pipe1enters one side of the ball core7from the valve body8, and the right connecting pipe11is positioned on the right side of the valve body8. The nuts include a left nut and a right nut9, wherein the left nut is used to fix the left connecting pipe1, and the right nut9is used to fix the right connecting pipe11. The sealing gaskets include a left sealing gasket3and a right sealing gasket10, wherein the left sealing gasket3is positioned between the valve seat gland4and the left connecting pipe1, and the right sealing gasket10is positioned between the valve body8and the right connecting pipe11.

The contact surfaces of the valve seat gland4and the connecting pipes15with the left sealing gasket between the valve seat gland4and the connecting pipes15are all external conical surfaces, and an included angle between a radial cross section of each of the valve seat gland4and the connecting pipes15and the corresponding external conical surface is 5-30°, and preferably 5-15°. The front and back surfaces of the left sealing gasket3between the valve and the left connecting pipe1are both internal conical shapes with its cross section being in an inverted trapezoidal shape, with a thin inner part and a thick outer part, and the included angle (bevel angle) a between a radial cross section of each of the valve seat gland4and the connecting pipes15and the corresponding internal conical surface is 5-30°, and preferably 5-15°. The left sealing gasket3is made of a plastic filler such as polytetrafluoroethylene (PTFE), carbon fiber reinforced polytetrafluoroethylene (CFRP), or para-polyphenyl (PPL). The pore size of the left sealing gasket is equal to the diameter of the ball core7, with the diameter of the ball core7being not reduced, a through hole14is formed in the ball core, and the diameter of the through hole14is equal to the inner diameter of the pipelines13.

The valve seat gland4is arranged in the valve body8, the inside of the valve seat gland4is in contact with the valve seat5, and the outside of the valve seat gland4is in contact with the left sealing gasket3. The contact surface of the valve seat gland4and the left sealing gasket3is an external conical surface, and the included angle (bevel angle) a between a radial cross section of the valve seat gland4and the external conical surface is 5-30°, and preferably 5-15°. The hole of the valve seat gland4is an inner hexagon, an inner octagon or an inner decagon.

Referring toFIG.3, the sealing surface of the flange of the left connecting pipe1is an external conical shape, and the included angle (bevel angle) a between the radial cross section of the left connecting pipe1and the external conical surface is 5-30°, and preferably 5-15°. The bevel angle between the valve seat gland4and the left sealing gasket3is equal to the bevel angle between the flange of the left connecting pipe1and the left sealing gasket3, and the internal conical surfaces and the external conical surfaces are completely attached after the valve assembly.

One half of the inside of the left side (close to the ball core during mounting) of the valve body8is a smooth inner circular surface (close to the outside), and the other half thereof is an internal thread (close to the inside). The clearance (difference in radius) between the left sealing gasket3and the valve body8is 0.05 mm to 0.5 mm, and preferably 0.1 mm to 0.3 mm.

During the valve assembly, after the valve seat gland4is mounted, the left sealing gasket3and the left connecting pipe1are sequentially placed into the valve body8, and then the left nut is mounted. Tightening the left nut will make the left connecting pipe1move inwards, and the left sealing gasket3, due to its special structure of an inverted trapezoidal shape, expands outwards after being extruded, and is close to the smooth inner circular surface of the valve body8, and when the nuts are tightened, the outer circular surface of the left sealing gasket3is attached to the smooth inner circular surface of the valve body8, forming sealing. At the moment, the valve seat gland4, the left sealing gasket3and the left connecting pipe1are also attached together to form sealing. When in use, under the action of the internal pressure, the left sealing gasket3expands outwards, making the sealing strengthened.

In some embodiments, the valve body8is connected to the pipeline13by a loose joint, the internally-sealed one-piece external thread ball valve and the pipeline have a nominal diameter of a caliber of 8 mm to 65 mm, and preferably 10 mm to 50 mm.

In another embodiment, the valve body8is in flange connection or inclined-plane clamp connection (CN 106439313 B, WO 2018/024174 A1) with the pipelines13, and the internally-sealed one-piece external thread ball valve has a nominal diameter of a caliber of 50 mm to 200 mm.

The internally-sealed one-piece external thread ball valve according to one embodiment has the advantages of easiness in machining, low manufacturing cost, reliability in sealing and high pressure resistance. In the present invention, the valve body8and the valve seat gland4can be respectively manufactured according to the normal valve production procedure, with simplified production process and reduced cost, and in addition, the universality of parts of the valve is good.

In some embodiments, the internally-sealed one-piece external thread ball valve has a lower manufacturing cost than the externally-sealed ball valve. Specifically, firstly, the left sealing gasket3are small in size, so that the using amount of sealing materials is small; secondly, the thickness of the valve body8can be thinned, for low-pressure external thread ball valve, on the basis of meeting the standard thickness of the valve body, the thickness of the externally-sealed external thread valve needs to be increased in order to ensure sealing surfaces with enough size (on the valve body, the width is 3-4 mm), and however, the internally-sealed one-piece external thread ball valve in this embodiment does not need to do the same; and thirdly, the machining process is simplified during manufacturing, so that the procedures are less. When the externally-sealed external thread ball valve is subjected to a very high pressure, the trapezoidal sealing gaskets may be deformed and then extruded into the threads of the nuts, so that the sealing gaskets cannot reuse, while the internally-sealed one-piece external thread ball valve in this embodiment does not have this problem.

The test result shows that the sealing material adopts carbon fiber reinforced polytetrafluoroethylene with certain elasticity, the usable fit tolerance of the left sealing gasket3and the valve body8is 0.2-0.8 mm (difference in diameter), the loose joints are disassembled after pressure test, clearances are formed between the left sealing gasket3and the valve body8, the left sealing gasket3are easy to take out, and the left sealing gasket3can be used repeatedly.

The right side of the valve is connected with the pipelines13by using welding type loose joints, and the right sealing gasket10is a metal triangular ring (CN 204717181 U) or a metal bow-shaped ring (CN 106352181 A, WO 2018/072522A1), and other sealing gaskets may also be adopted.

The valves currently used in industry have a nominal diameter of a minimum caliber of 15 mm, which is mainly due to the fact that the pipeline is unmatched with the flange of a large size. After the loose joints are popularized in industry, the valve having a nominal diameter of 10 may also be popularized, and therefore, the internally-sealed one-piece external thread ball valve is designed to have a nominal diameter of a caliber of 10 mm to 50 mm. In the prior art, a method for changing the diameter of the valve stem is adopted, the height of a packing box of a screw thread type ball valve is doubled, the packing box is designed according to the standard of a petrochemical ball valve, and a gland is provided with a pressure ring, so that the defect that the packing box of the screw thread type ball valve is not in accordance with chemical and petrochemical requirements is overcome; however, the improvement is designed for a two-piece external thread ball valve, and the valve stem6of the internally-sealed one-piece external thread ball valve is more difficult to mount. During design, the problem cannot be overcome by using the internally-sealed one-piece external thread ball valve having a nominal diameter of a caliber of 20 or below and adopting the method for changing the diameter of the valve stem6, namely, when a packing box is designed according to the standard of petrochemical and industrial ball valves, the valve stem6is too long to mount. In order to solve the problem, the valve stem6of the ball valves DN20, DN15 and DN10 in this embodiment is designed into two sections, with the two sections being in keyway connection with each other.

The internally-sealed one-piece external thread ball valve in this embodiment may also be used for manufacturing a large-caliber one-piece ball valve. Most of the large-caliber ball valves commercially available in the market at present are two-piece type, and one-piece type is rare. In recent years, an Italian one-piece ball valve appears in the Chinese market, with a nominal diameter of a caliber being 65 mm to 150 mm and the weight being much lighter than a two-piece ball valve, which is popular with chemical plants. If the large-caliber one-piece ball valve is the internally-sealed one-piece external thread ball valve in this embodiment, the manufacture is easier than the sealing of the existing asbestos plate (or stainless steel-graphite wound) flat gasket, and the weight of the valve is lightened. If the inclined-plane clamp connection with the pipelines proposed by the inventor is adopted (CN 106439313 B), compared with the existing two-piece flange ball valve, the weight will be reduced by 50-70%, and the price will be reduced by more than half.

In some embodiments, the internally-sealed one-piece external thread ball valve can be used for low-pressure, medium-pressure and high-pressure inflammable and explosive media. The internally-sealed one-piece external thread ball valve can replace a small-caliber flange ball valve in the chemical industry, with the manufacturing cost of the valve being reduced by 70-80% and the price being reduced by times, so that the internally-sealed one-piece external thread ball valve has great significance in popularization in the chemical industry. Compared with a flange ball valve, the internally-sealed one-piece external thread ball valve is convenient to mount, so that the mounting cost of chemical manufacturing is saved, and the steel is saved, with the steel for valve manufacturing being reduced by 70-80%, which contributes greatly to environmental protection, energy conservation and emission reduction. The internally-sealed one-piece external thread ball valve can be applied in the industries of general chemical industry, petroleum, petrochemical industry, power generation, steel making and the like, and used for process pipelines of heavy industry.

In some embodiments, the sealing material of the DN25 internally-sealed one-piece external thread ball valve is carbon fiber reinforced polytetrafluoroethylene, with the bevel angle α=7.5°. A common integral valve stem has a diameter of 9 mm with threads M8 at the upper end. The sealing gasket in movable connection with the right side (connected with the loose joint side) of the valve is a metal bow-shaped ring, with the specification of the nuts of M42×2. The length of the valve body is 75 mm, and the total length of the valve with loose joints mounted at two ends thereof is 183 mm, and the weight of the valve is 1.7 kg. The left side (close to the ball core) of the valve body8has an specification of external threads of M52×2 and an specification of internal threads of M44×2, and an inner diameter of the smooth surface of 44 mm. Three types of left sealing gasket3are made, the outer diameters thereof are 43.2 mm, 43.5 mm and 43.8 mm respectively, and the clearances between the left sealing gasket3and the valve body8are 0.4 mm, 0.25 mm and 0.1 mm respectively. After the valve assembly, the valve is tested on a special pressure testing machine for a loose-joint ball valve; the valve is immersed in water, the air pressure is 0.8 MPa, and no bubbles are generated. The valve is taken out from the pressure testing machine and disassembled for observation, wherein there are clearances between the left sealing gasket3and the valve body8, which proves that the sealing gaskets have certain elasticity and can be used repeatedly.

For a stainless steel DN25PN16 flange ball valve in the prior art, flanges are mounted at two ends thereof, bolts are mounted, and the weight is 6.97 kg. The weight of the flange ball valve is 4.1 times of that of the loose-joint ball valve.

In some embodiments, the sealing gasket of the DN15 internally-sealed one-piece external thread ball valve is made of carbon fiber reinforced polytetrafluoroethylene. The valve stem6is of an upper-lower segmented structure, the diameter of the valve stem6is 9 mm, and the upper-segmented structure is provided with threads M8 at the upper end. The sealing gasket in movable connection with the right side of the valve is a metal bow-shaped ring, with the specification of the nuts of M28×2. The length of the valve body8is 40 mm, and the total length of the valve with loose joints mounted at two ends thereof is 154 mm, and the weight of the valve is 1.0 kg. The specification of external threads on the left side of the valve body8is M42×2 and the specification of internal threads thereon is M32×2, and the inner diameter of the smooth surface is 32 mm. The outer diameter of the left sealing gasket3is 31.5 mm, and the clearance between each left sealing gasket3and the valve body8is 0.25 mm. After the valve assembly, the valve is tested on a special pressure testing machine for a loose-joint ball valve; the valve is immersed in water, the air pressure is 0.8 MPa, and no bubbles are generated. The valve is taken out from the pressure testing machine and disassembled for observation, wherein there are clearances between the left sealing gasket3and the valve body8, and thus the sealing gaskets can be used repeatedly.

For a stainless steel DN15PN16 flange ball valve in the prior art, flanges are mounted at two ends thereof, bolts are mounted, and the weight is 4.38 kg. The weight of the flange ball valve is 4.3 times of that of the loose-joint ball valve.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. All equivalent structural changes made from the specification and the drawings of the present invention, or direct/indirect application of the content of the present invention in other related technical fields under the inventive concept of the present invention, are included in the protection scope of the present invention.