valve manufacturer Archives

Principles of valve selection in the petroleum and chemical industry

September 14, 2020

Faced with so many valve classifications and such complex various working conditions, to choose the most suitable

lug type butterfly valve, ductile iron, center lined,

valve product for piping system installation, you should first understand the characteristics of the valve; secondly, you should master the steps and basis for selecting the valve; and then you should follow the choice of oil , The principle of valves used in the chemical industry. The principle of selecting valves in the petroleum and chemical industries: the flow path is a straight-through valve, and its flow resistance is small, and it is usually selected as a shut-off and open medium valve; a valve that is easy to adjust the flow is used as a control flow; a plug valve and a ball valve are more suitable Used for reversing and shunting; the sliding of the closing part along the sealing surface of the valve with wiping effect is most suitable for the medium with suspended particles.

1. Valves for shut-off and open media: The flow channel is a straight-through valve with low flow resistance. It is usually selected as a valve for shut-off and open media. The downward closing valve (stop valve, plunger valve) is less used because of its tortuous flow path and higher flow resistance than other valves. Where higher flow resistance is allowed, a closed valve can be used.

Globe valve (9)

2. Valves used for flow control: Generally, valves that are easy to adjust flow are selected as flow control valves. Downward closing valves (such as globe valves) are suitable for this purpose because the size of its seat is proportional to the stroke of the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and flex-body valves (pinch valves, diaphragm valves) can also be used for throttling control, but they are usually only applicable in a limited range of valve diameters. The gate valve uses a disc-shaped gate to cross-cut the circular valve seat port. It can only control the flow better when it is close to the closed position, so it is usually not used for flow control. 3. Valves for reversing and shunting According to the needs of reversing and shunting, this kind of valve can have three or more channels. Plug valves and ball valves are more suitable for this purpose. Therefore, most of the valves used for reversing and splitting use one of the plug valves and ball valves. However, in some cases, other types of valves can also be used for reversing and shunting as long as two or more valves are properly connected to each other.

4. Valves for medium with suspended particles When there are suspended particles in the medium, it is most suitable for valves with a wiping effect on the sliding of the closing part along the sealing surface. If the back and forth movement of the closing member to the valve seat is vertical, it may hold particles. Therefore, unless the sealing surface material allows particles to be embedded, this valve is only suitable for basic clean media. Ball valves, plug valves, and butterfly valves have a wiping effect on the sealing surface during opening and closing, so they are suitable for use in media with suspended particles.

At present, no matter in the pipeline system of petroleum, chemical industry, or other industries, valve applications, operating frequencies and services are ever-changing. To control or eliminate even low-level leakage, the most important and critical equipment is still valves. The ultimate control of the pipeline is the valve. The service and reliable performance of the valve in various industries are unique.

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

Description of valve pressure& installation direction requirements

September 14, 2020

As the name implies, the pressure of the valve refers to the pressure that the valve can withstand, that is, the

double-wing-check-valve-3

pressure level of the valve is not lower than the design pressure level of the pipeline. The pressure-bearing direction refers to the closed state of the valve after the valve is applied to the pipeline conditions. The arrow direction of the valve body is the recommended pressure-bearing direction. If it is installed incorrectly, the leakage failure of the valve may not be tightly closed. Generally, it is determined according to the use process or usage conditions. The same direction refers to the pressure-bearing direction (the side with high medium pressure on both sides of the valve gate) and the flow direction, and the opposite direction refers to the pressure-bearing direction (both sides of the valve gate) The side with high medium pressure) is opposite to the flow direction of the medium.

Many valves are directional, such as stop valves, throttle valves, pressure reducing valves, check valves, etc. If they are installed upside down, they will affect the use effect and life (such as throttle valves), or they will not work at all (such as Pressure reducing valve), or even cause danger (such as check valve). Normal valves have direction signs on the valve body; if not, they should be correctly identified according to the working principle of the valve.

The arrow marked on the valve body is the recommended pressure direction of the valve, not the flow direction of the pipeline medium. Valves with two-way sealing function may not be marked with an indicating arrow, or with an arrow, because the valve arrow refers to the recommended pressure direction. It is better to have one direction in the left and right or up and down directions. Usually used by the engineering installation company as the medium flow direction to mark the wrong installation, resulting in leakage or even pipeline accidents;

The valve cavity of the shut-off valve is asymmetrical left and right. The fluid must pass through the valve port from bottom to top, so that the fluid resistance is small (determined by the shape), and the opening is labor-saving (because the medium pressure is upward), and the medium does not press the packing after closing, which is convenient for maintenance . This is the reason why the globe valve cannot be reversed. Other valves also have their own characteristics. The location of the valve installation must be convenient for operation; even if the installation is temporarily difficult, it is necessary to consider the long-term work of the operator. It is best to keep the valve handwheel flush with the chest (usually 1.2 meters away from the operating floor), so that it is easier to open and close the valve. The hand wheel of the floor valve should be upward, not tilted, to avoid awkward operation. To

The valve of the wall machine and the equipment should also leave room for the operator to stand. It is necessary to avoid operating from the sky, especially acid and alkali, toxic media, etc., otherwise it is very unsafe. Do not install the gate valve upside down (that is, the handwheel is downward), otherwise the medium will remain in the valve cover space for a long time, which will easily corrode the valve stem, and it is contraindicated by certain process requirements. At the same time, it is extremely inconvenient to replace the packing. The exposed stem gate valve should not be installed underground, otherwise the exposed stem will be corroded due to moisture. When installing the lift check valve, ensure that its valve flap is vertical for flexible lifting. For the swing check valve, ensure that its pin shaft is level during installation to allow flexible swing. The pressure reducing valve should be installed upright on a horizontal pipe, and not inclined in all directions.

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

Valves’ sealing requirements and daily maintenance

August 18, 2020

The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent the leakage of the medium. It is the most important technical performance index of the valve. There are three sealing parts of the valve:

marine valve seat

the contact between the opening and closing parts and the two sealing surfaces of the valve seat; the matching place between the packing and the valve stem and the stuffing box; the connection between the valve body and the valve cover. One of the previous leakage is called internal leakage, which is commonly referred to as lax closure, which will affect the valve’s ability to cut off the medium. For shut-off valves, internal leakage is not allowed. The latter two leaks are called external leakage, that is, the medium leakage from the valve to the outside of the valve will cause material loss, pollute the environment, and cause accidents in severe cases. For flammable, explosive, toxic or radioactive media, leakage is not allowed, so the valve must have reliable sealing performance.

Daily maintenance of the valve:
1. Pay attention to the storage environment of the valve. It should be stored in a dry and ventilated room, and both ends of the passage should be blocked.

2. The valve should be inspected regularly, the dirt on it should be removed, and anti-rust oil should be applied to its surface.

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

3. The valve after installation and application should be overhauled regularly to ensure its normal operation.

4. Check whether the sealing surface of the valve is worn or not, and repair or replace it according to the situation.

5. Check the wear of the trapezoidal thread of the valve stem and the valve stem nut, whether the packing is out of date and invalid, etc., and replace it if necessary.

6. The sealing performance of the valve should be tested to ensure its performance.

7. The valve in operation should be intact, the bolts on the flange and the bracket are complete, the threads are not damaged, and there is no looseness.

8. If the handwheel is lost, it should be prepared in time and cannot be replaced with an adjustable wrench.

9. The packing gland is not allowed to be skewed or without pre-tightening clearance.

10. If the valve is used in a harsh environment and is easily contaminated by rain, snow, dust, sand and other dirt, a protective cover should be installed for the valve stem. 11. The ruler on the valve should be complete, accurate and clear, and the valve should be sealed and capped.

12. The insulation jacket should be free of dents and cracks.

13. Avoid hitting the valve during operation, or supporting heavy objects.

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

Installation attentions for valves

August 18, 2020

Precautions for valve installation:

Globe valves, throttle valves, pressure reducing valves, check valves and other valves are all directional. If the throttle valve is installed upside down, it will affect the use effect and life. If the pressure reducing valve does not work at all, if it is stopped The return valve can even cause danger.

lift-swing-check-valve-2

Generally, the valve has a direction mark on the valve body; if not, it should be correctly identified according to the working principle of the valve.

The valve cavity of the shut-off valve is asymmetrical left and right, and the fluid must pass through the valve port from bottom to top, so that the fluid resistance is small (determined by the shape), and the opening is labor-saving (due to the upward pressure of the medium), and the medium does not press the packing after closing, which is convenient for maintenance . This is the reason why the globe valve cannot be reversed. Other valves also have their own characteristics.

The valve installation location must be convenient for operation; even if the installation is temporarily difficult, it is necessary to consider the long-term work of the operator.

It is best to keep the valve hand wheel flush with the chest (usually 1.2 meters away from the operating floor), so that opening and closing the valve is easier. The hand wheel of the floor valve should be upward, do not tilt, to avoid

Globe valve (9)

awkward operation. The valve of the wall machine and the equipment should also leave room for the operator to stand. It is necessary to avoid operating from the sky, especially acid and alkali, toxic media, etc., otherwise it is very unsafe.

Do not install the gate valve upside down (that is, the handwheel is down), otherwise the medium will remain in the valve cover space for a long time, which will easily corrode the valve stem, and it is taboo for certain process requirements. At the same time, it is extremely inconvenient to replace the packing.

1. The pressure reducing valve should be installed upright on the horizontal pipeline, and not inclined in all directions.

2. As for the lift check valve, make sure its valve flap is vertical when installing it so that it can be lifted flexibly.

3. Swing check valve, ensure that its pin shaft is level when installing, so that it can swing flexibly.

4. Do not install the rising stem gate valve underground, otherwise the exposed stem will be corroded due to moisture.

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…)

Current status and development of Chinese valves

August 18, 2020

Domestic status: In terms of technical support for valve production and R&D, domestic valves are not lagging behind foreign valves. On the contrary, many products are comparable to international companies in terms of technology

lug type butterfly valve-ductile iron

and innovation. The development of the domestic valve industry should move towards high-end modernization.

Driven by the four major forces of industrialization, urbanization, reform and globalization, the prospects of my country’s valve equipment manufacturing industry are still broad. In the future, high-end, localization, and modernization of the valve industry will be the main development direction of the valve industry in the future. Pursuing continuous innovation and creating a new market for valve companies can enable companies to survive and develop in the increasingly competitive pump and valve industry.

With the continuous development of valve technology and the continuous expansion of valve application fields, corresponding valve standards are becoming more and more indispensable. The valve industry products have entered a period of innovation. Not only the product categories need to be updated, but the internal management of the enterprise also needs to deepen the reform according to the industry standards.

Therefore, it is necessary to make full use of existing standards while looking forward to the future, and to develop new standards and new systems that can be used in the future, so as to promote the higher-level development of valve technology. In the future, the valve industry will develop in two main directions: one is to develop from a single variety to multiple varieties and specifications; the other is to develop in the direction of energy saving.

According to industry insiders, pump and valve companies can only effectively and clearly understand the status quo of the industry, continuously strengthen and optimize their products, strengthen their awareness of danger, strengthen corporate culture and market service concepts, and only achieve fastness in stability, refinement in fastness, and stability in refinement. Only in this way can companies survive and develop in the increasingly competitive pump and valve industry.

The society is an era of information explosion. It is inevitable for companies to encounter competitors in products. There is competition in the industry, which is a good thing for some companies. Because of competition, enterprises have improved the quality of products and services, and consumers have obtained better or more consumption and services with less money. The market is a “screen”. While the industry is developing and progressing, the market is also surviving the fittest enterprises in the industry. Although the current status of the development of the butterfly valve industry is gaining momentum, the national support policies have been greatly improved, and the market demand has continued to increase. Due to the fierce competition in the industry, the pump and valve industry has also made domestic pump and valve related technologies to improve, but many interference factors indicate The development prospects of the pump valve industry are not optimistic.

For some large competitive enterprises, through competition, the scale of the enterprise has become larger and larger, and the popularity has become higher and higher. However, for some small and medium-sized enterprises that are not competitive, they may face the risk of being merged or going bankrupt. In the increasingly fierce valve market, only companies with core competitiveness can gain a foothold in the market, and innovation becomes a weapon for companies to win the market.

Valve cleaning steps and assembly requirements

August 18, 2020

Valve cleaning steps:

The valve parts must go through the following processes before assembly:

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

According to the processing requirements, some parts need to be polished, and the surface must not have processing burrs, etc.;
All parts are degreased;
After degreasing is completed, pickling passivation is carried out, and the cleaning agent does not contain phosphorus;
Rinse with pure water after pickling and purification, and there should be no residues of medicament, and this step is omitted for carbon steel parts;
Dry the parts one by one with a non-woven cloth, and do not leave the surface of the parts such as wire wool or dry with clean nitrogen;
Use non-woven fabric or precision filter paper dipped in analytical pure alcohol to wipe each part until there is no dirty color.

Valve assembly requirements:

The cleaned parts must be sealed and stored for installation. The requirements for the installation process are as follows:

The installation workshop must be clean, or set up a temporary clean area, such as newly purchased color striped cloth or plastic film, to prevent dust from entering during the installation process.
Assemblers must wear clean cotton overalls, cotton caps, no leakage of hair, clean shoes on feet, and plastic gloves on hands.
Assembly tools must be degreased and cleaned before assembly to ensure cleanliness.

other requirements:

1. Purge the assembled valve with nitrogen for at least 1 minute.
2. The air tightness test must use pure nitrogen.
3. After passing the air tightness test, encapsulate and seal with a clean polyethylene cap. The polyethylene cap should be soaked in organic solvent and wiped clean before use.
4. Then seal it with a vacuum bag.
5. Final packing.
6. Measures must be taken to ensure that the package is not damaged during transportation.
4. Acceptance requirements
The acceptance is followed. Before assembly, each component is wiped with clean precision filter paper. If the dead corner of the component is selected, the filter paper does not change color as qualified.

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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

What are the accessories for pneumatic valves?

August 18, 2020

Pneumatic valves have the advantages of fast switching and low price. Correct selection of pneumatic valves requires the use and characteristics of related accessories to achieve stable performance and long service life. In addition to improving the quality of the valve, it is also The matching of accessories is also very important. Here, I will introduce the characteristics and uses of several main accessories of pneumatic valves.

pnumatic actuator for butterfly valve

Accessory 1: Solenoid valve

The exact name of the solenoid valve should be the electromagnetic directional valve. The solenoid valve equipped with pneumatic valve mainly has two five-way and two-way three-way. The two-position five-way solenoid valve is usually used in conjunction with a double-acting pneumatic actuator, and the two-position three-way solenoid valve is used in conjunction with a single-acting pneumatic actuator. The pneumatic valve is used to switch the air intake and the air source through the solenoid valve. The air is discharged to achieve the function of opening and closing the valve. The solenoid valve has a single electric control solenoid valve and a double electric control solenoid valve. Explosion-proof solenoid valves should be used in special flammable and explosive occasions.

5 double-eccentric-butterfly-valve-2

Accessory 2: Limit switch

The limit switch is a long-distance transmission signal for opening or closing of the valve. The explosion-proof limit switch should be used in special flammable and explosive occasions.

Accessories 3: Air source treatment triple

Air source treatment triples include pressure reducer, filter, and oil mist device. The pressure reducer is mainly used to stabilize the air source and can adjust the pressure of the cylinder. The greater the pressure, the faster the valve opening and closing speed, which increases the friction of the valve and easily damages the sealing ring, thus affecting the service life of the valve; filter and The lubricator can filter the impurities in the air, clean and automatically add lubricant to the cylinder. Therefore, we recommend that the user is equipped with a three-piece valve for each valve, so that the pneumatic actuator can be better maintained and used for a longer time.

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.

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