KR200274149Y1 - cryogenic service butterfly valve for lng ship - Google Patents

Abstract

The present invention relates to a cryogenic butterfly valve for LNG carriers, and the body and the bonnet constituting the valve by a casting method, and the FEM (Finite) for the disc, body, shaft, and bonnet which are the main parts of the valve. Element Method-Finite element analysis-) Structural analysis ensures durability and low temperature confidentiality, which can be used as valves for refrigeration and low temperature facilities such as LNG carriers, LNG take-up and transport unloading facilities, heat-resistant power generation, and liquefied gas industry It is designed to use a valve that ensures the safe use of the valve when the valve contact temperature is -196 ° low temperature.

Description

Cryogenic butterfly valve for lng carrier {cryogenic service butterfly valve for lng ship}

The present invention relates to an ultra low temperature butterfly valve for LNG carriers. Specifically, the valve is used for refrigeration and low temperature facilities such as LNG carriers, LENG take-up water and transport unloading facilities, heat-resistant power generation, and liquefied gas industry. At temperatures close to -196 °, the valve can be used to ensure safe use of the valve.

In general, in order to block or maintain the flow of various fluids such as water, oil or sea water for industrial plants, a number of butterfly valves which are lighter than general valves and have a smooth opening and closing operation are installed and used. .

The butterfly valves used in this way have a sealing function that blocks or opens the fluid. The butterfly valve is provided with a sealing function by contacting a sheet of rubber formed on the disk with a metal valve flange or a metal disk with a valve seat formed with a rubber sheet. In this configuration, the disk of the valve is formed axially on the flange of the valve, and in the process of joining the disk to the valve flange, through the rubber seat formed on the disk or the valve flange, the airtightness of the valve flange and the disk It is to use as a valve for transferring the fluid through the pipeline in such a way that the fluid to be moved to the pipeline is blocked or opened by joining the sheets to be in close contact with each other.

The use of such a valve does not maintain the ultra low temperature even if the temperature of the fluid passing through the pipeline of the valve is low, so it is not difficult to use it as a valve for general fluid transfer. There is a problem that the valve does not withstand the temperature of the fluid.

With the development and expansion of natural gas, the demand for clean fuel (LNG) is increasing rapidly, but the transportation method is sporadically existing except for land connection and extremely pipelines. Ships are the only means of transport from natural gas fields.

However, due to the characteristics of LENGG, it is stored and transported in a liquid state maintained at high pressure and ultra low temperature of -160 ° C or lower, and there are no butterfly valves having good physical and chemical characteristics under these environmental conditions. There was a problem that can not be transferred to the pipe using a butterfly valve.

The present invention, in view of the above problems, in order to ensure the stable use of the valve at -196 ℃ low temperature state, the body of the valve and the configuration of the bonnet by the casting method, the main parts of the valve disk, body 'FEM' (Finite Element Method-finite element analysis-) structural analysis for the, shaft, bonnet to maintain durability and low temperature, as described in detail by the accompanying drawings as follows.

1 is a block diagram of the subject innovation

Figure 2 is a longitudinal cross-sectional view of the present invention

3 is an enlarged view of part (A) of FIG.

Explanation of symbols for main parts of the drawings

1; stainless steel casting body 2; stainless steel casting bonnet

3; disk 4; stem 5; primary metal sheet 6; secondary PTFE

7; butterfly valve

The above-mentioned disk 3 connected to the shaft 4 formed by eccentricity, which comprises the body 1 and the bonnet 2 by casting stainless steel, connects the disk 3 to the body 1, and is formed eccentrically. The shape of the structure is composed of a double eccentric structure in which the occlusal surface is spherical processed, and the structure of the sheet formed on the disk 3 is formed of the primary metal sheet 5 and the secondary PTFE 6, and the disk 3 The packing chamber of the valve generated in) is composed of graphite designed with an extension structure.

If the present invention described in detail described in detail,

In the present invention, the structure of the body 1 and the bonnet 2 should be less deformed by the pressure and temperature of the fluid in the line, and should have sufficient strength to withstand the internal pressure and temperature, and the flange can be fastened with the mating flange. As a type it provides space for assembling the stem 4 and the seats 5 and 6 and other parts such as actuators, while at the same time the body 1 or the bonnet ( 2) has a structure that can be tightened with a bolt, and also formed an expansion bonnet (2) to prevent freezing even if the temperature drops below -196 ℃, the body (1) inside because it is in direct contact with the fluid The most reliable cryogenic cast stainless steel withstands extreme conditions.

In the present invention, the structure of the disk 3 is a disk 3 which serves to control or block the flow of the fluid in a state fixed to a body inner diameter of a size substantially similar to that of the pipeline. A range in which the amount of deformation of the disk 3 can sufficiently cope with a certain load so that it must have sufficient strength to withstand and maintain the airtightness of the shaft 4 assembled to the body 1 or the disk 3. It is configured to listen to.

In addition, by repeating the opening and closing of the valve (7) to eliminate unnecessary contact with the shaft (4) to improve the durability, and to the structure that obstructs the flow of fluid in the pipeline, to minimize the generation of vortex and vacuum, the fluid It is designed to reduce the head loss caused when passing through.

In the present invention, the cryogenic disk 3 uses a double eccentric assembly on the shaft 4 where it is moved from the center of the disk 3, so that the disk 3 moves when the disk 3 is opened. This eliminates unnecessary contact with the shaft 4 and prevents abrasion from the surface of the disk 3 by cobalt alloy, and improves the service life due to such structural characteristics, thereby extending the durability. .

In addition, the occlusal surface of the disk 3 in contact with the primary metal sheet 5 is spherical processed so that the amount of interference with the primary metal sheet 5 can be uniformly ensured.

In the present invention, the stem 4 connects the body 1 and the disk 3 of the valve 7 to transmit the rotational motion to the disk 3 so that the disk 4 can be operated and the flow of fluid in the tube. And the torsional moment generated when the position of the disc 3 changes, and is configured to have sufficient strength in the case of delivery to the actuator or vice versa.

In particular, the cryogenic butterfly valve 7 is composed of a single body, and the shaft 4 and the disk 3 are firmly connected to prevent fluid leakage during use, and the material used may be sufficiently formed in the cryogenic polar acid state. It is composed of stainless steel, and the position of the shaft used for the valve 7 is composed of an eccentric shaft which is moved from the center, thereby enabling uninterrupted contact with the primary metal sheet 5 and the secondary PTFE 6. .

In the present invention, the primary metal seat (5) and the secondary PTFE (6) are configured to maintain perfect airtightness in both directions, and are characterized by high pressure and -196 ° C or less due to the characteristics of the cryogenic butterfly valve (7). The primary metal sheet 5 is made of stainless steel so that the secondary sheet is made of PTFE (6), which is reliable in the cryogenic state, and the amount of interference with the disk (3). It is composed of a structure that can be minimized and free from unnecessary deformation before the airtight state.

In the present invention, the seal is formed in the expansion structure so that the packing gland may relieve the pressure in preparation for the extremely low temperature extreme, and the packing part is capable of exchanging the seal without removing the shaft from the valve. The material is composed of graphite in consideration of temperature, pressure conditions, etc. The 'FEM' used in the present invention is the 'Finite Element Method', which uses a computer program to design the structure and strength of the valve. 'PTFE' is an abbreviation of 'Poly Tetra Flouord Ethyline' and describes TOW-COAT type fluorine resin (highest use temperature) among DUPONT's fluoride carbide-based trademarks. .

As described in detail above, the valve 7 made of cast stainless steel can maintain safety in transporting fluid even in an ultra low temperature state, and is excellent in durability and airtightness, and together with the gate valve. There is an effect that the butterfly valve 7 can be used as a valve for LENG carrier.

Claims (1)

The above-mentioned disk 3 connected to the shaft 4 formed by eccentricity, which comprises the body 1 and the bonnet 2 by casting stainless steel, connects the disk 3 to the body 1, and is formed eccentrically. The shape of the structure is composed of a double eccentric structure in which the occlusal surface is spherical processed, and the structure of the sheet formed on the disk 3 is formed of the primary metal sheet 5 and the secondary PTFE 6, and the disk 3 The packing chamber of the valve generated in the) is composed of graphite (graphit) designed in an expansion structure, cryogenic butterfly valve for an LG carrier.