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What is the material of Bolts and nuts of Valve Stem?

August 17, 2020

bolts and nuts for butterfly valve

The stem nut directly bears the axial force of the stem during the opening and closing of the valve, so it must have a certain strength. At the same time, it and the valve stem are threaded transmission, which requires a small friction coefficient, no rust and avoid seizure.

1. Copper alloy Copper alloy has a small friction coefficient and does not rust. It is one of the commonly used materials. For low pressure valves with Pg<1.6Mpa, ZHMn58-2-2 cast brass can be used. ZQAL9-4 Wuxi bronze can be used for Pg16-6.4Mpa medium pressure valve. For high-pressure valves, ZHAL66-6-3-2 cast brass can be used.

2. Steel When the working conditions do not allow the use of copper alloys, high-quality carbon steels such as 35 and 40 can be selected, and stainless acid-resistant steels such as 2Cr13, 1Cr18Ni9, and Cr17Ni2 can be used. Working conditions are not allowed to refer to the following situations.

1. For electric valves, stem nuts with melon clutches need heat treatment to obtain high hardness or surface hardness.

2. When the working medium or the surrounding environment is not suitable for copper alloy, such as ammonia medium that corrodes copper. When selecting steel stem nuts, pay special attention to thread seizure.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest valve bolts and nuts manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

What is the material of the butterfly valve stem?

August 17, 2020

Stem material classification:
During the opening and closing of the butterfly valve, the valve stem bears the forces of tension, pressure and

buttefly valve stem shaft parts (6)

torsion, and is in direct contact with the medium. At the same time, there is relative frictional movement with the packing. Therefore, the valve stem material must ensure that there is enough at the specified temperature Strength and impact toughness, a certain degree of corrosion resistance and scratch resistance, and good manufacturability. The commonly used stem materials are as follows.

1. When carbon steel is used in water and steam medium with low pressure and medium temperature not exceeding 300℃, A5 ordinary carbon steel is generally used. When used in water and steam medium with medium pressure and medium temperature not exceeding 450℃, 35 high-quality carbon steel is generally used.

2. When alloy steel is used for medium pressure and high pressure, and the medium temperature does not exceed 450 ℃ water, steam, petroleum and other media, 40Cr (chromium steel) is generally used. 38CrMoALA nitriding steel can be used when it is used in water, steam and other media with high pressure and medium temperature not exceeding 540℃. 25Cr2MoVA chromium molybdenum vanadium steel is generally used when used in high pressure steam medium with medium temperature not exceeding 570℃.

3. Stainless acid-resistant steel S is used for non-corrosive and weakly corrosive media with medium and high pressure and medium temperature not exceeding 450℃. 1Cr13, 2Cr13, 3Cr13 chromium stainless steel can be selected. When used in corrosive media, stainless acid-resistant steel such as Cr17Ni2, 1Cr18Ni9Ti, Cr18Ni12Mo2Ti, Cr18Ni12Mo3Ti, and PH15-7Mo precipitation hardening steel can be selected.

4. When heat-resistant steel is used for high-temperature valves whose medium temperature does not exceed 600℃, 4Cr10Si2Mo martensitic heat-resistant steel and 4Cr14Ni14W2Mo austenitic heat-resistant steel can be selected.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest valve stem/shaft manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

What is the material of the main parts of the butterfly valve?-(2)

August 17, 2020

Selection of valve sealing material:

Sealing surface material: The sealing surface is the most critical working surface of the valve. The quality of the

marine valve seat

sealing surface is related to the service life of the valve. Generally, the sealing surface material should consider factors such as corrosion resistance, scratch resistance, erosion resistance, and oxidation resistance. Usually divided into two categories:

(1) Soft materials of butterfly valve:

Rubber (including nitrile rubber, fluorine rubber, etc.)
Plastics (polytetrafluoroethylene, nylon, etc.)

(2) Hard sealing material of butterfly valve:

Copper alloy (used for low pressure valves)
Chrome stainless steel (used for ordinary high and medium pressure valves)
Stellite alloy (used for high temperature and high pressure valves and strong corrosion valves)
Nickel-based alloy (used for corrosive media)

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

What is the material of the main parts of the butterfly valve?-(1)

August 17, 2020

Selection of butterfly valve parts materials:
There are many materials for manufacturing butterfly valves, including ferrous and non-ferrous metals and their

16 U-type-flange-butterfly-vlave-body

alloys of different brands, and various non-metallic materials. The materials for manufacturing valve parts should be selected based on the following factors:

1. Pressure, temperature and characteristics of working medium.

2. The force of the part and its function in the valve structure.

3. It has better manufacturability.

4. If the above conditions are met, there must be a lower cost.

The material of the valve body, bonnet and disc (disc) The body, bonnet and gate (disc) are one of the main parts of the valve, which directly bear the pressure of the medium, and the material used must meet the “pressure and temperature rating of the valve” Provisions.

Commonly used material types for butterfly valves:

1. Gray cast iron: Gray cast iron is suitable for water, steam, air, gas, oil and other media with a nominal pressure of PN≤1.0MPa and a temperature of -10℃~200℃. The commonly used grades of gray cast iron are: HT200, HT250, HT300, HT350.

2. Malleable cast iron: Suitable for water, steam, air and oil media with a nominal pressure

17 center-line-butterfly-valve-plate-disc-parts-4

of PN≤2.5MPa and a temperature of -30~300℃. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.

3. Ductile iron: suitable for water, steam, air and oil with PN≤4.0MPa and temperature of -30~350℃. Commonly used grades are: QT400-15, QT450-10, QT500-7. In view of the current level of domestic technology, the plants are uneven, and users are often not easy to inspect. According to experience, it is recommended that PN≤2.5MPa, and the valve should be made of steel for safety.

4. Acid-resistant high-silicon ductile iron: suitable for corrosive media with nominal pressure PN≤0.25MPa and temperature below 120℃.

5. Carbon steel: suitable for water, steam, air, hydrogen, ammonia, nitrogen and petroleum products with a nominal pressure of PN≤32.0MPa and a temperature of -30~425℃. Commonly used grades are WC1, WCB, ZG25 and high-quality steel 20, 25, 30 and low-alloy structural steel 16Mn. Six, copper alloy: suitable for water, sea water, oxygen, air, oil and other media with PN ≤ 2.5MPa, and steam media with a temperature of -40 to 250 ℃, commonly used brands are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (Brass), QAZ19-2, QA19-4 (aluminum bronze).

18 buttefly-valve-stem-shaft-parts-1

7. High temperature steel: suitable for steam and petroleum products with nominal pressure PN≤17.0MPA and temperature≤570℃. Commonly used grades are ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9, etc. The specific selection must be in accordance with the valve pressure and temperature specifications. 8. Low temperature steel, suitable for nominal pressure PN≤6.4Mpa, temperature≥—196℃ ethylene, propylene, liquid natural gas, liquid nitrogen and other media, commonly used grades) ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.

9. Stainless acid-resistant steel, suitable for nitric acid, acetic acid and other media with nominal pressure PN≤6.4Mpa and temperature≤200℃. Commonly used grades are ZG0Cr18Ni9Ti, ZG0Cr18Ni10<nitric acid>, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti<acid and urea>.

Strainer valve introduction and its features

August 17, 2020

STRAINER VALVE, also known as filter: a device for filtering pretreatment. The filter valve is the filter equipment necessary for the use of hydraulic control valves and precise and easy-to-clog mechanical products.

Strainer valve Introduction:
STRAINER VALVE, also known as filter: a device for filtering pretreatment. The filter valve is the filter equipment necessary for the use of hydraulic control valves and precise and easy-to-clog

15 Y-type-strainer-filter-valve-7

Y type strainer filter valve (11)

mechanical products. It is an indispensable device in the pipeline series that transports the medium. It is usually installed at the inlet of hydraulic control valves, pressure relief valves, pressure relief valves, fixed water level valves and other equipment to eliminate impurities in the medium and prevent particulate impurities from entering The channel causes wall plugs to protect the fittings on the equipment pipeline from wear and blockage. When cleaning is needed, just take out the detachable filter cartridge and reinstall it after treatment. Therefore, the use and maintenance are extremely convenient.

Features of filter valve:
The filter valve mesh adopts a stainless steel double-layer mesh structure, which is sturdy and durable. It has the characteristics of advanced structure, low flow resistance, and convenient sewage discharge. It can be used for water, steam, oil, nitric acid, urea, oxidizing media and other media. The mesh number of the filter screen should be set according to the user’s needs. Generally, the water network is 18-30 mesh, the ventilation network is 40-100 mesh, and the oil network is 100-480 mesh. The Y-type filter can also be combined with the telescopic joint to form a Y-type pull rod telescopic filter with adjustable installation length. The filter screen can be made according to user requirements.

Filter valve performance parameters:
Connection method: flange, butt welding, thread
Nominal pressure/MPa: 1.0-2.5
Pressure test pressure/MPa: 1.1-2.75
Working pressure/MPa 1.0 -2.5
Shell material: gray cast iron. ductile iron. carbon steel. stainless steel
Filter material: stainless steel
Total mesh area: 3～4DN

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Daily maintenance and precautions of ball valves

August 14, 2020

Daily maintenance of ball valve:
Long service life and maintenance-free period will depend on the following factors: normal working conditions, maintaining a harmonious temperature/pressure ratio, and reasonable corrosion data.

14 ball-valve-6

When the ball valve is closed, there is still pressurized fluid inside the valve body.

Before maintenance: relieve the pipeline pressure and leave the valve in the open position; disconnect the power or air source; separate the actuator from the bracket.

It is necessary to find out that the upstream and downstream pipelines of the ball valve have indeed been relieved of pressure before disassembling.

Care must be taken to prevent damage to the sealing surface of parts, especially non-metal parts, when disassembling and reassembling. Special tools should be used when removing O-rings.

The bolts on the flange must be tightened symmetrically, gradually and evenly during assembly.

The cleaning agent should be compatible with the rubber parts, plastic parts, metal parts and working medium (such as gas) in the ball valve. When the working medium is gas, gasoline (GB484-89) can be used to clean metal parts. Clean non-metal parts with pure water or alcohol.

Non-metal parts should be taken out of the cleaning agent immediately after cleaning, and should not be soaked for a long time.

After cleaning, it needs to be assembled after the cleaning agent of the wall surface to be washed evaporates (can be wiped with silk cloth not soaked in cleaning agent), but it should not be left for a long time, otherwise it will rust and be contaminated by dust.

New parts also need to be cleaned before assembly.

When assembling, it should not be allowed to have metal chips, fibers, grease (except those specified for use), dust, other impurities, foreign objects, etc., to contaminate, adhere or stay on the surface of the parts or enter the cavity. Then tighten the stem nut.

Note: Don’t lock it too tightly, usually lock 1/4 turn to 1 turn, the leakage will stop.

A), disassembly

Keep the valve in a half-open position to flush and remove dangerous substances that may exist inside and outside the valve.

Close the ball valve, remove the connecting bolts and nuts on both flanges, and then completely remove the valve from the pipeline.

Disassemble the drive device-actuator, connecting bracket, lock washer, stem nut, butterfly shrapnel, glam, wear-resistant piece, stem packing in order.

Remove the body cover connecting bolts and nuts, separate the valve cover from the valve body, and remove the valve cover gasket.

Make sure that the valve ball is in the “off” position. This will make it easier to take it out of the valve body, and then take out the valve seat.

Gently push the stem down from the hole in the valve body until it is completely taken out, and then take out the O-ring and the lower packing of the stem.

Note: Please operate carefully to avoid scratching the surface of the valve stem and the sealing part of the valve body stuffing box.

B), reassembly

Clean and inspect the removed parts. It is strongly recommended to replace the valve seat and valve cover gasket with spare parts kit.

Assemble in the reverse order of disassembly.

Use the specified torque to tighten the flange connecting bolts crosswise.

Tighten the stem nut with the specified torque.

After installing the actuator, input the corresponding signal to drive the valve core to rotate by rotating the valve stem to make the valve open and close.

If possible, please perform pressure seal test and performance test on the valve according to relevant standards before reinstalling the pipeline.

Applicable occasions and operation method of ball valve

August 14, 2020

Applicable occasions of ball valve:
Since the ball valve usually uses rubber, nylon and polytetrafluoroethylene as the seat sealing ring material, its use temperature is limited by the seat sealing ring material. The cut-off effect of the ball valve is accomplished by

14 ball-valve-6

pressing the metal ball against each other between the plastic valve seats under the action of the medium (floating ball valve). Under the action of certain contact pressure, the seat sealing ring has elastic-plastic deformation in some areas. This deformation can compensate the manufacturing accuracy and surface roughness of the ball, and ensure the sealing performance of the ball valve.

In addition, since the seat sealing ring of the ball valve is usually made of plastic, when selecting the structure and performance of the ball valve, the fire resistance and fire resistance of the ball valve must be considered, especially in the petroleum, chemical, metallurgical and other sectors, in the flammable and explosive media Ball valves are used in the equipment and piping systems, and more attention should be paid to fire and fire resistance.

Generally, in two-position adjustment, strict sealing performance, mud, wear, necking channel, rapid opening and closing action (1/4 turn opening and closing), high pressure cut-off (large pressure difference), low noise, cavitation and vaporization, In piping systems with a small amount of leakage to the atmosphere, small operating torque and low fluid resistance, ball valves are recommended.

Ball valves are also suitable for piping systems with light structure, low pressure cut-off (small pressure difference), and corrosive media. Ball valves can also be used in cryogenic (cryogenic) devices and pipeline systems. In the oxygen pipeline system of the metallurgical industry, ball valves that have undergone strict degreasing treatment are required. When the main line in the oil pipeline and gas pipeline needs to be buried underground, full-diameter welded ball valves are required. When the adjustment performance is required, a ball valve with a special structure with a V-shaped opening should be selected. In petroleum, petrochemical, chemical, electric power, and urban construction, metal-to-metal sealed ball valves can be used for pipeline systems with operating temperatures above 200 degrees.

Operation method of ball valve:
1) Before operation, make sure that the pipeline and valve have been flushed.

2) The operation of the valve drives the valve stem to complete rotation according to the size of the input signal of the actuator: when it rotates 1/4 turn (90°) in the forward direction, the valve is closed. When reverse rotation is 1/4 turn (90°), the valve opens.

3) When the actuator direction indicator arrow is parallel to the pipeline, the valve is open; when the indicator arrow is perpendicular to the pipeline, the valve is closed.

Hard seal installation method of ball valve

August 14, 2020

Hard seal installation method of ball valve:

1) Remove the protective covers on both sides of the flange, and rinse and clean with the valve fully opened.

ball valve (6)

2) Before installation, the whole machine should be tested according to the specified signal (electrical or pneumatic) (to prevent vibration caused by transportation from affecting the performance), and then it can be installed online (wiring according to the electric actuator circuit diagram).
3) Before preparing to connect with the pipeline, flush and remove the remaining impurities in the pipeline (these substances may damage the valve seat and ball).
4) During installation, please do not use the actuator part of the valve as a lifting point to avoid damage to the actuator and accessories.
5) This type of valve should be installed in the horizontal or vertical direction of the pipeline.
6) The pipeline near the installation point should not be drooping or bear external force. Pipe supports or supports can be used to eliminate pipeline deviation.
7) After connecting with the pipeline, please cross-tighten the flange connecting bolts with the specified torque.

Tianjin Tanghai Valve Manufacturing Co., Ltd. is one of the largest ball valve manufacturers in China, main products are butterfly valves, check valves, gate valve and globe valves. Key words: butterfly valve, lug type butterfly valve, wafer type butterfly valve, U-type butterfly valve, double flange butterfly valve, gate valves, check valves, globe valves, valve parts (Valve body, Valve disc, Valve shaft, Valve seat…)

Installation instructions for ball valves

August 14, 2020

Installation instructions for ball valves:

1. Indoor devices or outdoor applications with protective methods;

ball valve (7)

2. Outdoor installations are corroded by wind, sand, rain, dew, and sunlight;
3. Have flammable, explosive gas or dust environment;
4. Humid tropical and dry tropical environment;
5. The temperature of the pipeline medium is as high as 450℃;
6. The ambient temperature is lower than -20℃;
7. Easy to be flooded or immersed in water;
8. Possess a radioactive material (nuclear power plant and radioactive material test device) environment;
9.The environment on the ship or dock (with salt spray, mold, humidity);
10.Occasions with severe vibration; occasions prone to fire;

For the electric ball valve in the above environment, the electric device structure, material and protection method are different. Therefore, the corresponding valve electric device should be selected according to the above-mentioned obligation environment. According to engineering control requirements, for electric ball valves, their control functions are completed by electric devices. The purpose of applying electric ball valves is to complete non-manual electrical control or computer control of valve opening, closing and adjustment linkage. The application of electric devices is not just for diligence and labor saving. Since the functions and quality of products from different manufacturers are quite different, the selection of electric devices and the selection of valves are equally important to the project. As the requirements of industrial automation level are constantly improving, on the one hand, the application of electric valves is increasing, and on the other hand, the control requirements for electric valves are getting higher and higher and more complicated. Therefore, the design of electric valves in electrical control is always updated. With the continuous improvement of use requirements and the popularization and application of computers, new and diverse electrical control methods will always appear. Regarding the overall control of the electric valve, attention should be paid to the selection of the control method of the electric valve. For example, depending on the needs of the project, whether to use a centralized control method or a single control method, whether to link with other equipment, sequence control or application computer sequence control, etc., the control principles are different. The sample of valve electric device manufacturers only gives standard electric control principles, so the application department should make technical clarifications with the electric device consumer to understand the technical requirements.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

The parameter and troubleshooting of the ball valve

August 14, 2020

The parameter level of the ball valve:

1. Nominal pressure or pressure level: PN1.0-32.0MPa, ANSI CLASS 150-900, JIS10-20K;

14 ball-valve-6

2. Nominal diameter or caliber: DN6～900, NPS 1/4 ～36;

3. Connection method: flange, butt welding, thread, socket welding, etc.;

4. Applicable temperature: -196℃～540℃;

5. Drive mode: manual, worm gear drive, pneumatic, electric, hydraulic, gas-liquid linkage, electro-hydraulic linkage;

6. Valve body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. Different materials are used, which can be applied to various media such as water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea, etc.

Pressure limit of ball valve:
The nameplate shows the maximum allowable operating pressure of the ball valve at the maximum and minimum operating temperatures.

Seats and seals made of PTFE or RTFE are used. The operating temperature of other types of seat and seals should be checked by the KI factory.

The nominal pressure rating (PN) of the valve can indicate the maximum working pressure of the valve under normal temperature conditions. (For example: PN4.0, indicating that the maximum working pressure is 40 Bar (4.0MPa) when the operating temperature is between -190C and 380C).

For the precautions of electric or pneumatic actuators, refer to their corresponding instructions.

Troubleshooting of the ball valve:
The ball valve has been scoured by the material for a long time, causing friction, causing severe impact and abrasion, which cannot meet the normal production, and at the same time, the equipment life is shortened. At present, wear-resistant materials, such as ceramic materials and polymer composite materials, are mostly used for the wear of ball valves, and there are more technical systems used. The polymer material has superior adhesion performance, super wear resistance, and safely solves the disadvantages of frequent metal wear and ensures the normal production of enterprise equipment. Moreover, the unique ceramic material and special surface strengthening agent in the material make it better than any steel or even ceramic tile in wear resistance and physical impact resistance in the harshest dry grinding environment. The incompatibility of the product with coal is to prevent Ideal material for coal deposits.

What is the material of Bolts and nuts of Valve Stem?

What is the material of the butterfly valve stem?

What is the material of the main parts of the butterfly valve?-(2)

What is the material of the main parts of the butterfly valve?-(1)

Strainer valve introduction and its features

Daily maintenance and precautions of ball valves

Applicable occasions and operation method of ball valve

Hard seal installation method of ball valve

Installation instructions for ball valves

The parameter and troubleshooting of the ball valve

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