applications Archives

The chemical composition, characteristics and applications of rubbers

December 30, 2020

Here we will introduce Rubber variety (abbreviated symbol) with their Chemical composition, Performance characteristics and Main application.

1. Natural rubber (NR) is mainly rubber hydrocarbon (polyisoprene), containing a small amount of protein, moisture, resin acid, sugar and inorganic salt. Large elasticity, high tensile strength, excellent tear resistance and electrical insulation, good wear resistance and drought resistance, good processability, easy to bond with other materials, and superior to most synthetic rubbers in comprehensive performance. Disadvantages are poor resistance to oxygen and ozone, easy to aging and deterioration; poor resistance to oil and solvents, low resistance to acid and alkali, and low heat resistance. Operating temperature range: about -60℃~+80℃. Production of tires, rubber shoes, hoses, tapes, insulation layers and sheaths of wires and cables, and other general products. It is especially suitable for manufacturing torsional vibration eliminators, engine shock absorbers, machine supports, rubber-metal

lug type butterfly valve-ductile iron

suspension components, diaphragms, and molded products.

2. Styrene butadiene rubber (SBR) is a copolymer of butadiene and styrene.
The performance is close to natural rubber, and it is currently the largest output of general-purpose synthetic rubber. It is characterized by abrasion resistance, aging resistance and heat resistance exceeding natural rubber, and its texture is more uniform than natural rubber. The disadvantages are: low elasticity, poor flex resistance and tear resistance; poor processing performance, especially poor self-adhesiveness and low green rubber strength. Operating temperature range: about -50℃~＋100℃.
Mainly used to replace natural rubber to make tires, rubber sheets, hoses, rubber shoes and other general products.

3. Butadiene rubber (BR)
It is a cis-structure rubber formed by polymerization of butadiene. The advantages are: excellent elasticity and wear resistance, good aging resistance, excellent low temperature resistance, low heat generation under dynamic load, and easy metal bonding. The disadvantages are low strength, poor tear resistance, poor processing performance and self-adhesiveness. Operating temperature range: about -60℃~＋100℃.
Generally used together with natural rubber or styrene-butadiene rubber, mainly to make tire treads, conveyor belts and special cold-resistant products.

4. Isoprene rubber (IR) is a kind of cis structure rubber made by polymerization of isoprene monomer. The che

Wafer butterfly valve-PN20-WCB-ANSI-150 (4)

mical composition and three-dimensional structure are similar to natural rubber, and the performance is very close to natural rubber, so it is called synthetic natural rubber. It has most of the advantages of natural rubber. Due to its aging resistance, natural rubber has slightly lower elasticity and strength than natural rubber, poor processing performance and higher cost. Operating temperature range: about -50℃~+100℃ It can replace natural rubber to make tires, rubber shoes, hoses, tapes and other general products.

5. Chloroprene rubber (CR) is a polymer formed by emulsion polymerization of chloroprene as monomer.
This kind of rubber contains chlorine atoms in its molecule, so compared with other general rubbers: it has excellent antioxidant, ozone resistance, non-flammable, self-extinguishing after fire, oil resistance, solvent resistance, acid and alkali resistance, aging and gas resistance. Advantages such as good tightness;
Its physical and mechanical properties are also better than natural rubber, so it can be used as general-purpose rubber as well as special rubber. The main disadvantages are poor cold resistance, large specific gravity, high relative cost, poor electrical insulation, and easy sticking, scorching, and mold sticking during processing. In addition, the raw rubber has poor stability and is not easy to store. Operating temperature range: about -45℃~＋100℃. It is mainly used to manufacture cable sheaths and various protective covers and protective covers that require high ozone resistance and high aging resistance; oil and chemical resistance hoses, tapes and chemical linings; flame-resistant rubber products for underground mining, and various moldings Products, sealing rings, gaskets, adhesives, etc.

6. Butyl rubber (IIR) is a copolymer of isobutylene and a small amount of isoprene or butadiene. The biggest feature is good air tightness, good ozone resistance, good aging resistance, high heat resistance, long-term working temperature can be below 130 ℃; resistance to strong inorganic acids (such as sulfuric acid, nitric acid, etc.) and general organic solvents, vibration absorption and damping characteristics Good and very good electrical insulation. The disadvantages are poor elasticity, poor processing performance, slow vulcanization speed, and poor adhesion and oil resistance. Operating temperature range: about -40℃~+120℃. Mainly used as inner tube, water tyre, balloon, wire and cable insulation layer, chemical equipment lining and shockproof products, heat-resistant conveyor belt, heat-resistant aging tape products.

7. Butadiene rubber (NBR) Copolymer of butadiene and acrylonitrile. It is characterized by its excellent resistance to gasoline and aliphatic hydrocarbon oils, second only to polysulfide rubber, acrylic ester and fluorine rubber, but better than other general rubbers. Good heat resistance, good air tightness, abrasion resistance and water resistance, and strong adhesion. The disadvantages are poor cold resistance and ozone resistance, low strength and elasticity, poor acid resistance, poor electrical insulation, and poor resistance to polar solvents. Operating temperature range: about -30℃~＋100℃. Mainly used to manufacture various oil-resistant products, such as hoses, sealing products, etc.

8. Hydrogenated butadiene rubber (HNBR) is a copolymer of butadiene and acrylonitrile. It is obtained by fully or partially hydrogenating the double bonds in the butadiene of NBR.
It is characterized by high mechanical strength and abrasion resistance, and its heat resistance is better than NBR when crosslinked with peroxide
Good, other properties are the same as nitrile rubber. The disadvantage is that the price is higher. Operating temperature range: about -30℃~+150℃. Mainly used for oil and high temperature resistant sealing products.

9. Ethylene propylene rubber (EPM\\EPDM)
The copolymer of ethylene and propylene is generally divided into two yuan ethylene propylene rubber and three yuan ethylene propylene rubber.
It is characterized by excellent ozone resistance, ultraviolet resistance, weather resistance and aging resistance, ranking first in general rubber. Electrical insulation, chemical resistance, impact elasticity, acid and alkali resistance, low specific gravity, high filling compounding is possible. Heat resistance up to 150°C, resistance to polar solvents-ketones, esters, etc., but not to aliphatic and aromatic hydrocarbons. Other physical and mechanical properties are slightly inferior to natural rubber and superior to styrene butadiene rubber. The disadvantage is that the self-adhesion and mutual adhesion are very poor, and it is not easy to bond. Operating temperature range: about -50℃~+150℃. Mainly used as chemical equipment lining, wire and cable sheathing, steam hose, heat-resistant conveyor belt, rubber products for automobiles and other industrial products.

10. Silicone rubber (Q)
It is a special rubber with silicon and oxygen atoms in the main chain, of which silicon element plays a major role. Its main feature is high temperature resistance (maximum 300℃) and low temperature resistance (minimum -100℃). It is currently the best high temperature resistant rubber. It has excellent electrical insulation and high stability to thermal oxidation and ozone. , Chemically inert. The disadvantage is that the mechanical strength is low, oil resistance, solvent resistance, acid and alkali resistance are poor, it is difficult to vulcanize, and the price is more expensive. Operating temperature: -60℃~+200℃.

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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…)

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Email: harry@tanghaivalve.com

Uses and characteristics of manual butterfly valve (4)

July 21, 2020

Installation and maintenance of manual butterfly valve:
During installation, the disc should stop in the closed position. The opening position should be determined according to the rotation angle of the butterfly plate. For

wafer type butterfly valve, with handle (13)

the butterfly valve with bypass valve, the bypass valve should be opened before opening, and the installation should be carried out according to the manufacturer’s installation instructions. The heavy butterfly valve should be set with a firm foundation.

Comparison of ordinary butterfly valve and gate valve:

Which of the ordinary butterfly valve or gate valve with the same nominal pressure and nominal diameter has better tightness and is not easy to leak?

The airtightness of the gate valve is better than that of the butterfly valve, but there are also manufacturers’ butterfly valves that have better airtightness. This type of valve should generally be installed horizontally in the pipeline.

The gate valve is large in size and takes up a lot of space.

The butterfly valve is small in size and takes up little space.

When selecting, the temperature of the medium, the sealing of the valve and the packing must also be considered.

The specification stipulates that butterfly valves with a nominal diameter greater than 50 are used.

The elastic metal sealing butterfly valve is a national key new product. The high-performance manual butterfly valve adopts a double eccentric and a special oblique cone oval sealing structure. It solves the shortcoming of the traditional eccentric butterfly valve that the sealing surface is still in sliding contact friction at the moment of opening and closing 0°～10°, and the sealing surface of the butterfly plate is separated at the moment of opening, and the effect of sealing when the contact is closed is achieved. Good purpose.

Material of manual butterfly valve:
1. Valve body material: gray cast iron, ductile iron, cast steel, aluminum alloy, stainless steel, etc.;

2. Valve plate material: duplex stainless steel, nylon 11 plate, galvanized plate, aluminum bronze;

3. Valve seat material: nitrile rubber, EPDM, fluorine rubber, silicone rubber, PTFE.

Ranges of application for manual butterfly valve:
It is widely used in the pipelines of petroleum, chemical, food, medicine, papermaking, hydropower, shipbuilding, water supply and drainage, metallurgy, oil, energy and other systems. It is suitable for a variety of corrosive gases, liquids, semi-liquid and solid powder media.

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

Uses and characteristics of manual butterfly valve (3)

July 21, 2020

Features of manual butterfly valve:
The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve opening and closing or adjustment of the valve is called a butterfly valve. The butterfly valve is usually less than 900 from fully open to fully closed. The butterfly valve and the butterfly rod

Double flange butterfly valve (7)

themselves are not self-locking. For the positioning of the butterfly plate, a worm gear reducer must be installed on the valve rod. The use of worm gear reducer can not only make the butterfly plate have self-locking ability, make the butterfly plate stop at any position, but also improve the operation performance of the valve. Industrial-specific butterfly valves are characterized by high temperature resistance, high applicable pressure range, large nominal diameter of the valve, the valve body is made of carbon steel, and the sealing ring of the valve plate uses a metal ring instead of a rubber ring. Large high-temperature butterfly valves are manufactured by welding steel plates, and are mainly used for flue ducts and gas pipes for high-temperature media.

Advantages of manual butterfly valve:
The opening and closing is convenient and rapid, labor-saving, low fluid resistance, and can be operated frequently. Simple structure, small size and light weight. Mud can be transported, with the least accumulation of liquid at the pipe mouth. Under low pressure, good sealing can be achieved. Good adjustment performance.

Disadvantages of manual butterfly valves:
1. Use pressure and working temperature range are small.
2. Poor airtightness.

Classification of manufal butterfly valve:
According to the structure, it can be divided into offset plate type, vertical plate type, inclined plate type and lever type. According to the sealing form, it can be divided into two types: soft sealing type and hard sealing type. The soft seal type generally uses a rubber ring seal, and the hard seal type generally uses a metal ring seal. According to the connection type, it can be divided into flange connection and wafer connection; according to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.

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

Uses and characteristics of manual butterfly valve (2)

July 21, 2020

Uses/application of manual butterfly valve:
Used in the gas pipeline in the sulfuric acid industry: the inlet and outlet of the blower in front of the furnace, the inlet and outlet of the relay fan, the electric demisting series and the connecting valve, the inlet and outlet of the S02 main blower, the adjustment of the converter, the inlet and outlet of the preheater, etc. and

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

the use of cut-off gas.

It is used in the sulfur burning, conversion and dry absorption sections of the sulfur-burning sulphuric acid plant. It is the preferred brand of valves for the sulphur-burning sulphuric acid plant. It is regarded by the majority of users as: good sealing performance, light operation, secondary corrosion, high temperature resistance, convenient operation, The flexible, safe and reliable butterfly valve has been widely used.

It is also widely used in: SO2, steam, air, gas, ammonia, CO2, oil, water, brine, lye, seawater, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid in the chemical, petrochemical, smelting, pharmaceutical, food and other industries It is used as a regulating and intercepting device on the pipeline of other medium.

Structural features of manual butterfly valve:

The unique design of three-way eccentricity enables frictionless transmission between the sealing surfaces and prolongs the service life of the valve.
Elastic seal is produced by torque.
The clever wedge-shaped design enables the valve to have an automatic sealing function that is tighter and tighter, and the sealing surfaces are compensated and leak-free.
Small size, light weight, light operation and easy installation.
Pneumatic and electric devices can be configured according to user requirements to meet the needs of remote control and program control.
The material of replacement parts can be applied to various media, and can be lining anti-corrosion (lining F46, GXPP, PO, etc.).
Diversified continuous structure: wafer, flange, butt welding.

Tianjin TanghaiDongyang Valve Co., Ltd. is one of the largest butterfly valve manufacturers in China, main products are butterfly valves, check valves.

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

Posts

The chemical composition, characteristics and applications of rubbers

Uses and characteristics of manual butterfly valve (4)

Uses and characteristics of manual butterfly valve (3)

Uses and characteristics of manual butterfly valve (2)

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