valve parts Archives

Types of valve accessories

September 25, 2020

Types of valve accessories: The valve itself is composed of a valve body and various operating mechanisms, which also contain many parts and accessories, including manual, pneumatic, electric and so on. The components assembled in different ways of use are also different.
Valve accessories mainly include:
1. Pneumatic actuator: It is mainly divided into single-acting and double-acting. Single-acting is a spring-return

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

structure, and double-acting is the principle of air opening and closing. Generally, double-acting pneumatic actuators are used for adjustment types. 2. Electric actuators: the common ones are linear, angular, compact and explosion-proof. The structure of the electric actuator is relatively complex and the cost is high, but its performance is stable, open and close quickly, and it is suitable for remote control systems.
3. Hydraulic actuator: A hydraulic actuator is a device that converts hydraulic energy into mechanical energy. There are mainly linear and rotary types. The cost is relatively high and the structure is relatively complex. It is a product with special working conditions and high requirements, and the market generalization rate is low.
4. Gas-liquid linkage actuator: The gas-liquid linkage actuator uses pipeline natural gas or nitrogen as power and hydraulic oil as the transmission medium to drive the opening and closing of pipeline valves. It is mainly used as a multifunctional driving device in natural gas, liquefied gas, nitrogen, gas liquid tank, gas, etc.
5. Electro-hydraulic linkage actuator: The electro-hydraulic linkage actuator is composed of a control module and a power module. The intelligent controllable motor accepts the function commands of the control module, controls the power module, and outputs the large distance in line or angular displacement, pneumatic control The object, at the same time, completes the adjustment process through its own displacement feedback, and realizes various functional controls.
6. Manual actuator: The manual actuator is to perfect the manual control when the current is unstable and the air pressure is insufficient. When the air pressure and current cannot be controlled under special circumstances or there is no current and air pressure for installation and maintenance, the manual feedback device can be turned on, which can be carried out quickly Manual control.

Valve components:
Handle, handwheel, worm gear, valve body, valve core, valve stem, valve cover, valve silencer, blank, bolt and nut, clamp, spring, diaphragm, packing, packing, O-ring, PTFE products Gaskets, flanges, non-standard solid parts, etc.
Positioner and accessories:
Pneumatic valve positioner, electric valve positioner, intelligent valve positioner, electro-hydraulic server, servo amplifier, electric converter, filter pressure reducing valve, valve position transmitter, position valve, solenoid valve, limit switch, pneumatic Amplifier, smart module, electro-hydraulic server, servo amplifier, alarm, explosion-proof coil, quick exhaust valve
Other valve accessories:
Valve testing machine Handle Handwheel Worm gear valve Body Valve core Valve cover Valve silencer Signal generator Rough mold bolts and nuts Clamps Springs Diaphragm Packing O-rings Flow juice Polytetrafluoroethylene products Gaskets Flanges Fast elbows Joint expander Flow meter Filter non-standard solid parts

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

Valve material and valve standards-(9)- general valve & parts materials

September 9, 2020

General valve material
The internal material combination specified by API600 for general valve material:

Stem material types	hardness	sealing surface
Stem material types	hardness	seal part no.,	material type	hardness
13Cr	200-275	1	13Cr	≥HB250
		4	13Cr	≥HB750
		5 or 5A	HF	≥HB350
		6	13Cr/NiCu	≥HB750/≥HB175
		7	13Cr/13Cr	≥HB250/≥HB750
		8-8A	13Cr/HF	≥HB250/≥HB350
18Cr-8Ni	no require	2	18Cr-8Ni	no require
25Cr-20Ni		3	25Cr-20Ni
Nickel copper alloy		9	Nickel copper alloy
Nickel copper alloy		11 or 11A	Nickel copper alloy/HF	no require/≥HB350
18Cr-8Ni-Mo		10	18Cr-8Ni-Mo	no require
18Cr-8Ni-Mo		12 or 12A	18Cr-8Ni-Mo/HF	no require/≥HB350
19Cr-29Ni		13	19Cr-29Ni/HF	no require
19Cr-29Ni		14 or 14A	19Cr-29Ni/HF	no require/≥HB350

Commonly used valve trim material combination:

valve stem	sealing surface	valve stem	sealing surface
13Cr	13Cr/13Cr	321	321/321
13Cr	13Cr/STL	321	321/STL
13Cr	STL/STL	321	STL/STL
13Cr	13ZCr/Monel	1Cr18Ni9Ti	1Cr18Ni9Ti/1Cr18Ni9Ti
17-4PH	STL/STL	1Cr18Ni9Ti	1Cr18Ni9Ti/STL
17-4PH	17-4PH/17-4PH	1Cr18Ni9Ti	STL/STL
Monel	Monel/Monel	1Cr18Ni12Mo2Ti	1Cr18Ni12Mo2Ti/1Cr18Ni12Mo2Ti
304	304/304	1Cr18Ni12Mo2Ti	1Cr18Ni12Mo2Ti/STL
304	304/STL	1Cr18Ni12Mo2Ti	STL/STL
304	STL/STL	20 Alloy	20alloy/20alloy
316	316/316	Hastelloy B	Hastelloy B/Hastelloy B
316	316/STL	Hastelloy C	Hastelloy C/Hastelloy C
316	STL/STL	F51	F51/F51
304L	304L/304L	F51	F51/STL
304L	304L/STL	38CrMoALA	STL/STL
304L	STL/STL	25Cr2MoIV A	STL/STL
316L	316L/316L	4Cr10Si2Mo	STL/STL
316L	316L/STL	4Cr14Ni14W2Mo	STL/STL
316L	STL/STL	Inconel	Inconel/Inconel

Commonly used fastener material:

Bolts	Nuts	Max temp °C
35	25	425
35CrMo	35, 45	425
35CrMo	30CrMo	500
25Cr2MoVA	30CrMo	550
0Cr18Ni9	0Cr18Ni9	600
0Cr17Ni12Mo2	0Cr17Ni12Mo2	600
25Cr2Mo1VA	25Cr2Mo1VA	600
25Cr2MoVA	25Cr2MoVA	600

Matching materials of bolts and nuts for American standard valves:

Bolts		nuts		application temp
standard	grade name	standard	grade name	application temp
ASTM A193	B7	ASTM A194	2H	-29/425°C
	B7M		2HM	-29/425°C NACE standard, anti-sulfer valve
	B16		7	-29/593°C
	B8		8	-196/700°C
	B8M		8M	-196/700°C
ASTM A320	L7		4	-46/101°C Cryogenic valve

Chemical composition and mechanical properties of commonly used bolts and nuts for American standard valves:

Chemical composition and mechanical properties of commonly used bolts and nuts for American standard valves

Conditions of use of metal gaskets:

material	HB max	Pressure Mpa(lb)	suitable temp °C
10/08	120	2.0-42(150-2500)	450
0Cr13	170	2.0-15(150-900)	540
0Cr18Ni9	160		600
0Cr17Ni12Mo2	160		600

Spiral wound gasket service conditions:

metal belt material	Non-metallic belt material	Pressure grade Mpa (lb)	suitable temp °C
0Cr18Ni9	flexible graphite	2.0-26(150-1500)	650
0Cr17Ni12Mo2	flexible graphite		650
00Cr17Ni14Mo2	PTFE		200

Conditions for use of metal-clad gasket:

Cladding metal material	HB	filling material	pressure Mpa(lb)	suitable temp °C
Al L3	40	asbestos	2.0-15(150-900)	200
Co T3	60			300
Galvanized steel sheet	90			400
Galvanized steel sheet 08F	90			400
0Cr18Ni9	187			500
00Cr19Ni10
00Cr17Ni14Mo2

Use conditions of flexible graphite composite gasket:

Core board and edging material	pressure grade Mpa (lb)	suitable temp °C
low-carbon steel	2.0-11(150-600)	450
0Cr18Ni9	2.0-11(150-600)	650

Non-metallic gasket usage conditions:

material name	code name	pressure Mpa	suitable temperature °C
natural rubber	NR	2.0	-50/90
Neoprene	CR	2.0	-40/100
NBR	NBR	2.0	-30/110
Ethylbenzene rubber	SBR	2.0	-30/110
EPDM rubber	EPDM	2.0	-40/130
fluororubber	Viton	2.0	-50/200
Asbestos Rubber Sheet	XB350 XB450 NY400	2.0 ≤300 P.T≤650 Mpa °C
Oil-resistant asbestos rubber sheet	XB350 XB450 NY400	2.0 ≤300 P.T≤650 Mpa °C
Modified or filled with PTFE		5.0	-196/260

Comparison table of common metal materials specified by Chinese, Japanese, German, British, American and international standards:

Comparison table of common metal materials specified by Chinese, Japanese, German, British, American and international standards

WC carbon steel +A/B/C –WCA,WCB,WCC

WC carbon steel +ABC –WCA,WCB,WCC

Please see the Full documentation at this link: https://www.tanghaivalve.com/wp-content/uploads/2020/09/valve-material-and-valve-standards-Detailed-version.pdf

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

Valve material and valve standards-(2)-body stem bonnet material

August 27, 2020

Selection of valve material:
There are many materials for manufacturing valve parts, including various types of ferrous and non-ferrous metals and their alloys, and various non-metallic materials. The materials for manufacturing valve parts are selected

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

according to the following factors:
1. The pressure, temperature and characteristics of the working medium.
2. The force of the part and its function in the valve structure.
3. Have better manufacturability.
4. If the above conditions are met, there must be a lower cost.

Section one: the material of the valve body, bonnet and valve plate
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°C–200°C. The commonly used grades of gray cast iron are: HT200, HT250, HT300, HT500.

2.. Malleable cast iron: suitable for water, steam, air and oil media with a nominal pressure of PN≤2.5Mpa and a temperature of -30-300°C. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.

3. Nodular cast iron: suitable for water, steam, air and oil with PN≤4.0Mpa and temperature of -30-350°C. Commonly used grades are: QT400-15, QT450-10, QT500-7.

4. Carbon steel (WCA, WCB, WCC): Suitable for nominal pressure PN≤32MPa, suitable for medium and high pressure valves with operating temperature between -29°C and +425°C. Among them, 16Mn and 30Mn work at -29-595°C, and are often used to replace ASTM A105. Commonly used grades are WC1, WCB, ZG25 and high-quality steel 20, 25, 30 and low-alloy structural steel 16Mn.

5. Low temperature carbon steel (LCB): suitable for ethylene, propylene, liquid natural gas, liquid nitrogen and other media with nominal pressure PN≤6.4MPa and temperature ≥-196°C. Commonly used grades are ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.

6. Alloy steel (WC6, WC9), suitable for high temperature and high pressure valves with non-corrosive medium working temperature between -29-595°C; WC5, WC9 are suitable for working temperature between -29-659°C High temperature and high pressure valves for corrosive media.

7. Austenitic stainless steel, suitable for valves with corrosive media with working temperature between -196-600°C.
Eight. Monel alloy: mainly suitable for valves with hydrofluoric medium.
nine. Cast copper alloy: Mainly suitable for valves for oxygen pipelines whose operating temperature is between -29 and 595°C

Fig.1-1 Commonly used valve body material:

valve body material	standard	temp	PN/Mpa	medium
Grey cast Iron		-15/200	≤1.6	water,gas
Black Heart Malleable Cast Iron		-15/300	≤2.5	water, seawater, gas, Ammonia
ductile cast iron		-30/350	≤4.0	water,seawater,gas,air,steam
carbon steel (WCA,WCB,WCC)	ASTM A216	-29/425	≤32	non-corrosive water, oil, gas
Low temp carbon steel (LCB,LCC)	ASTM A352	-46/345	≤32	low temp application
Alloy（WC6，WC9，C5，C12）	ASTM A217	-29/595 -29/650	High pressure	non-corrosive corrosive medium
Austenitic stainless steel	ASTM A351	-196/600		corrosive medium
Monel alloy	ASTM A494	400		Hydrofluoric acid medium
Hastelloy	ASTM A494	649		Strong corrosive medium such as dilute sulfuric acid
Titanium alloy				Various strong corrosive media
Cast copper alloy		-273/200		Oxygen, sea water
Plastic, Ceramic		-60	≤1.6	corrosive medium

Name	material	standard	temp range °C	application
WCB	carbon steel	ASTM A216	-29/425	non-corrosive water, oil and gas
LCB	low temp carbon steel	ASTM A352	-46/345	low temp applicaion
LC3	3.5% nickel steel	ASTM A352	-101/340	low temp applicaion
WC6	1.25% chromium, 0.5% molybdenum	ASTM A217	-30/593	non-corrosive water, oil and gas
WC9	2.25% chromium	ASTM A217	-30/593	non-corrosive water, oil and gas
C5	5% chromium,0.5% molybdenum	ASTM A217	-30/649	light or non-corrosive application
C12	9% chromium 1% molybdenum	ASTM A217	-30/649	light or non-corrosive application
CA15(4)	12% chromium	ASTM A217	704	corrosive application
CA6NM(4)	12% chromium	ASTM A487	-30/482	corrosive application
CF8M	stainless steel 316	ASTM A351	-268/649 when <425, need C=0.04% info	corrosive,ultra low/high temp with no corrosive application
CF8C	stainless steel 347	ASTM A351	-268/649 when <425, need C=0.04% info	high temp, corrosive application
CF8	stainless steel 304	ASTM A351	-268/649 when <425, need C=0.04% info	corrosive,ultra low/high temp with no corrosive application
CF3	stainless steel 304L	ASTM A351	425	corrosive or non-corrosive
CF3M	stainless steel 316L	ASTM A351	454	corrosive or non-corrosive
CN7M	alloy	ASTM A351	425	Good resistance to hot sulfuric acid corrosion
M35-1	monel	ASTM A494	400	Weldable grade, good resistance to common organic acid and salt water corrosion, resistance to most alkaline solutions
N7M	Hastelloy B	ASTM A494	649	Suitable for treating various concentrations and temperatures of hydrofluoric acid, with good resistance to corrosion by sulfuric acid and phosphoric acid
CW6M	Hastelloy C	ASTM A494	649	Very good resistance to strong oxidation, resistance to phosphoric acid, sulfurous acid and sulfuric acid at high temperatures
CY40	Inconel alloy	ASTM A494		Resistant to strong corrosive fluids at high temperatures

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

Classification of valves

August 18, 2020

Valve classification by function and purpose:

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

(1) Cut-off type: such as gate valve, globe valve, plug valve, ball valve, butterfly valve, needle valve, diaphragm valve, etc. The cut-off valve is also called a closed-circuit valve or a cut-off valve, whose function is to connect or cut off the medium in the pipeline.

Check valve, also known as one-way valve or check valve, check valve is an automatic valve, its function is to prevent the back flow of the medium in the pipeline, prevent the pump and drive motor from reversing, and the leakage of the container medium . The bottom valve of the pump to close the water is also a check valve.

Explosion-proof valves, emergency valves, etc. The role of safety valves is to prevent the pressure of the medium in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

Regulating valve, throttle valve and pressure reducing valve, its role is to adjust the pressure, flow and other parameters of the medium.

(2) Vacuum: such as vacuum ball valve, vacuum baffle valve, vacuum charging valve, pneumatic vacuum valve, etc. Its role is in the vacuum system to change

The vacuum system components that adjust the air flow direction, cut off or connect the pipeline are called vacuum valves.

(3) Special purpose categories: such as pigging valve, vent valve, drain valve, exhaust valve, filter, etc. The exhaust valve is an indispensable auxiliary component in the pipeline system, which is widely used in boilers, air conditioners, oil and gas, and water supply and drainage pipelines. It is often installed at high points or elbows to remove excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption.

According to the main parameters:

According to the nominal pressure:

lug type butterfly valve, ductile iron, center lined,

(1) Vacuum valve: refers to a valve whose working pressure is lower than the standard atmospheric pressure.
(2) Low pressure valve: refers to the valve with a nominal pressure PN ≤ 1.6Mpa.
(3) Medium pressure valve: refers to valves with nominal pressure PN of 2.5Mpa, 4.0Mpa, 6.4Mpa.
(4) High-pressure valve: refers to the valve whose nominal pressure PN is 10.0Mpa~80.0Mpa.
(5) Ultra-high pressure valve: refers to a valve with a nominal pressure PN≥100.0Mpa.
(6) Filter: Refers to the nominal pressure PN is 1.0Mpa, 1.6Mpa

According to working temperature

(1) Ultra-low temperature valve: used for valves with medium working temperature t<-101℃.
(2) Normal temperature valve: used for valves with medium working temperature -29℃<t<120℃.
(3) Medium temperature valve: used for valves with a working temperature of 120℃<t<425℃.
(4) High temperature valve: used for valves with medium working temperature t>425℃.

By driving method:

According to the driving mode, it is divided into automatic valves, power-driven valves and manual valves

Valves driven by compressed air. Hydraulic valve: A valve driven by the pressure of liquids such as oil.

In addition, there are combinations of the above several driving methods, such as pneumatic-electric valves.

According to the nominal diameter:

(1) Small diameter valve: Valve with nominal diameter DN≤40mm.
(2) Middle diameter valve: a valve whose nominal diameter DN is 50~300mm.
(3) Large diameter valve: a valve with a nominal valve DN of 350~1200mm.
(4) Extra large diameter valves: valves with nominal diameter DN ≥ 1400mm

6. According to structural characteristics:

Valve structure characteristics:

The structural features of the valve can be divided into:

(1) Sectional gate shape: The closing part moves along the center of the valve seat; such as a globe valve
(2) Cock and ball: The closing part is a plunger or a ball, which rotates around its own centerline; such as a plug valve, a ball valve
(3) Gate shape: The closing part moves along the center of the vertical valve seat; such as gate valve, gate, etc.
(4) Swing shape: The closing part rotates around the axis outside the valve seat; such as swing check valve, etc.
(5) Butterfly shape: the disc of the closing part, which rotates around the axis in the valve seat; such as butterfly valve, butterfly check valve, etc.
(6) Slide valve shape: The closing piece slides in a direction perpendicular to the channel. Slippery

Press connection method:

(1) Threaded connection valve: The valve body has an internal thread or an external thread, which is connected with the pipe thread…
(2) Flange connection valve: The valve body has a flange and is connected to the pipeline flange.
(3) Welding connection valve: The valve body has a welding groove and is welded to the pipeline.
(4) Clamp connection valve: The valve body has a clamp, which is connected with the pipe clamp.
(5) Ferrule connection valve: the ferrule is connected to the pipeline.
(6) Wafer connection valve: a connection form in which the valve and two pipes are directly clamped together with bolts.

According to the body material

(1) Metal material valve: its valve body and other parts are made of metal material. Such as cast iron valves, cast steel valves, alloy steel valves, copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves, etc.
(2) Non-metallic material valve: its valve body and other parts are made of non-metallic material. Such as plastic valves, enamel valves, ceramic valves, FRP valves, etc.

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

Basic knowledge of valve

August 18, 2020

A valve is a device used to control the direction, pressure and flow of fluid in a fluid system. A valve is a device that allows the medium (liquid, gas, powder) in the piping and equipment to flow or stop and can control its flow.

lug type butterfly valve, ductile iron, center lined,

The valve is a control component in the pipeline fluid conveying system. It is used to change the passage section and the flow direction of the medium. It has the functions of diversion, cutoff, throttling, check, diversion or overflow pressure relief. Valves used for fluid control, from the simplest shut-off valves to the various valves used in extremely complex automatic control systems, have a wide range of varieties and specifications. The nominal diameter of the valve ranges from extremely small instrument valves to large diameters of 10m. Valves for industrial pipelines. The valve can be used to control the flow of various types of fluids such as water, steam, oil, gas, mud, various corrosive media, liquid metals, and radioactive fluids. The working pressure of the valve can be from 0.0013MPa to 1000MPa ultra-high pressure and working temperature From the ultra-low temperature of -270℃ to the high temperature of 1430℃. The valve can be controlled by a variety of transmission methods, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic hydraulic,

Electro-hydraulic, pneumatic-hydraulic, spur gear, bevel gear drive, etc.; it can act according to predetermined requirements under the action of pressure, temperature or other forms of sensing signals, or simply open or close without relying on sensing signals , The valve relies on the drive or automatic mechanism to make the opening and closing parts move up, down, sliding, swinging or rotating, thereby changing the size of the flow channel area to achieve its control function.

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

Fasteners, fillers and gasket materials of valves

August 17, 2020

There are many other valves parts and 1. Fastener material of valves:

valve bonnets

Fasteners mainly include bolts, studs and nuts. The fastener directly bears the pressure on the valve, which plays an important role in preventing the outflow of the medium. Therefore, the selected material must ensure sufficient strength and impact toughness at the operating temperature. When selecting fastener materials according to medium pressure and temperature, you can choose according to Table 5-1. Name Nominal Pressure Pg (Mpa) Medium Temperature (℃) 300 350 400 425 450 530 Bolt Stud Bolt 1.6-2.5 A3 35 30CrMoA _4.0-10.0 35 35CrMoA 25Cr2MoVA16.0-20.0 30CrMoA 35CrMoA 25Cr2MoVA Nut 1.6-2.5 A3 30 35 _4.0-10.0 30 35 35CrMoA16.0-20.2 35 35CrMoA Table 5-1 must undergo heat treatment when selecting alloy steel materials. When there are special corrosion resistance requirements for tight-return parts, stainless and acid-resistant steels such as Cr17Ni2, 2Cr13, 1Cr18Ni9 can be selected.

2. Filler material of valves:
On the valve, the packing is used to fill the space of the valve cover packing chamber to prevent the medium from leaking through the valve stem and the valve cover packing chamber space.

1. Requirements for packing 1) Good corrosion resistance, the packing must be able to withstand the corrosion of the medium in contact with the medium. 2) The sealing is good, and the packing will not leak under the action of the medium and working temperature. 3) The friction coefficient is small to reduce the friction torque between the valve stem and the packing.

2. Types of fillers Fillers can be divided into two types: soft fillers and hard fillers: 1) Soft fillers: are made of plant materials, namely hemp, flax, cotton, jute, etc., or are made of minerals, that is, asbestos fibers, or Wire ropes braided by asbestos fibers with metal wires inside and graphite powder coated on the outside, as well as pressed shaped fillers, and flexible graphite filler materials newly developed in recent years. Plant-based packing is cheaper, and is often used for low-pressure valves below 100°C; mineral packing can be used for valves with 450-500°C. In recent years, the structure of using rubber O-rings as packing has been gradually promoted, but the temperature of the medium is generally limited to below 60℃. The packing on the high temperature and high pressure valve is also compacted with pure asbestos and flake graphite powder. 2) Hard filler: that is, filler made of metal or metal mixed with asbestos and graphite and filler formed by pressing and sintering of polytetrafluoroethylene. Metal filler is used less.

3. The choice of packing The packing should be selected according to the medium, temperature and pressure. Commonly used materials are as follows: 1) Oil-impregnated asbestos rope, which can be selected according to Table 5-2. 2) Rubber asbestos rope: can be selected according to Table 5-3. 3) Graphite asbestos rope: The asbestos rope is coated with graphite powder. The usable temperature is above 450℃ and the pressure can reach 16Mpa. It is generally suitable for high-pressure steam. Lately, it gradually adopts the compression-shaped packing, which is placed in a single circle and has good sealing performance. 4) Polytetrafluoroethylene: This is a filler that is currently widely used. Especially suitable for corrosive media, but the temperature should not exceed 200℃. It is generally made by pressing or bar stock, and its shape is shown in Figure 5-1. Name, brand, shape and specification (diameter or square side length) Applicable ultimate pressure kgf/cm2 Applicable ultimate temperature (℃) Purpose Oil-impregnated asbestos rope YS450 F 3.4.5.6.8.10 13.16.19.22.25 60 450 For water vapor, air, petroleum Product Y 5.6.8.10.13 16.19.22.25N 3.5.6.8.10.13 16.19.22.25 YS350 F, Y, N 3.5.6.8.10.13 16.19.22.25. 45 350 YS250 F, Y, N 3.5.6.8.10.13. 16.19.22.25 45 250 Table 5-2 Note: The shape code F means square, through the core or one to multi-layer braid; Y means round, with a twisted core in the middle, and one to multi-layer braid on the outside; N means twisted. Name, grade and specification (straight formula or square side length) Applicable ultimate pressure kgf/cm2 Applicable ultimate temperature (℃) Purpose Rubber asbestos packing XS450 3.4.5.6.8 10.13.16.19 22.25.28 60 450 Used for steam and petroleum products XS350 45 350 XS250 45 250 Table 5-3

3. Gasket material:
The gasket is used to fill all the unevenness between the two joint surfaces (such as the sealing surface between the valve body and the valve cover) to prevent the medium from leaking between the joint surfaces. 1. Requirements for gaskets The gasket material has a certain degree of elasticity, plasticity and sufficient strength at working temperature to ensure sealing. At the same time, it must have good corrosion resistance. 2. Types and selection of gasket materials Gaskets can be divided into two types: soft and hard. The soft is generally non-metallic materials, such as cardboard, rubber, asbestos rubber sheet, and polytetrafluoroethylene. Hardness is generally metal material or metal-coated asbestos, metal and asbestos entangled, etc. There are many shapes of gaskets, including flat, round, oval, tooth-shaped, lens-shaped and other special shapes. Metal gaskets are generally made of 08, 10, 20 high-quality carbon steel and 1Cr13, 1Cr18Ni9 stainless steel, which require high machining accuracy and surface finish, and are suitable for high temperature and high pressure valves. Non-metallic gasket materials generally have good plasticity and can be sealed with less pressure. Suitable for low temperature and low pressure valves. The gasket material can be selected according to Table 5-4. Gasket material medium application range Pressure (Mpa) Temperature (℃) Thick cardboard water, oil ≤10 40 Oil-immersed cardboard water, oil ≤10 40 Rubber sheet water, air ≤6 50 Asbestos board steam, gas ≤6 450 poly Tetrafluoroethylene corrosive medium≤25 200 Rubber asbestos board XB-450 Water vapor, air, gas≤60 450XB-350 Water vapor, air, gas≤40 350XB-200 Water vapor, air, gas≤15 200 Oil-resistant rubber asbestos board oil Class 160 3008 steel and XB-450 filling steam 100 45008 steel and XB-350 filling steam 40 3501Cr13, 0Cr13 asbestos filling steam 100 60008 steel and oil-resistant rubber asbestos filling oil 100 350 copper water vapor, air 100 250 aluminum water vapor, air 64 35010 steel, 20 steel water steam, oil 200 4501Cr13 steam 200 5501Cr13Ni9 steam 200 600

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