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Concentric Type Butterfly valve with resilient seated

April 29, 2024

A concentric type butterfly valve with a resilient seat is a type of valve commonly used in various industries for flow control. Let’s break down its components:

Concentric Design: In this design, the centerline of the stem (the shaft that controls the opening and closing of the valve) is also the centerline of the disc (the “butterfly” part of the valve). This design allows for smooth flow regulation and minimal turbulence.

Butterfly Valve: This valve uses a disc as the flow control element. The disc is mounted on a shaft in the center of the valve’s body. When the valve is open, the disc is parallel to the flow, allowing fluid to pass through. When the valve is closed, the disc is perpendicular to the flow, blocking it.

Resilient Seat: The seat of the valve is the part where the disc makes contact when the valve is closed. Resilient seats are made from materials like EPDM (ethylene propylene diene monomer) or NBR (nitrile butadiene rubber). These materials are resilient, meaning they can deform slightly to ensure a tight seal when the valve is closed. Resilient seats also provide good resistance to wear and tear and are suitable for a wide range of operating temperatures.

wafer type double stems butterfly valve (2)

In practical terms, a concentric type butterfly valve with a resilient seat is often used in applications where a tight shut-off is required, such as in water treatment plants, HVAC systems, and various industrial processes. The resilient seat ensures a reliable seal, and the concentric design allows for smooth operation and minimal pressure drop across the valve.

wafer type butterfly valve (7)

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Wafer Concentric Type Butterfly Valve (tanghai valve)

April 11, 2024

A wafer concentric type butterfly valve is a type of butterfly valve commonly used in various industries, including marine applications. Here’s a brief overview of its features, selection considerations, and usage:

Features:

Concentric Design: The wafer concentric butterfly valve features a concentric design where the stem passes through the center of the disc, ensuring a uniform seal around the circumference. This design minimizes turbulence and pressure drop while providing efficient flow control.
Wafer Style: These valves have a wafer-style body, which means they fit between two flanges without the need for additional bolts or nuts. This compact design saves space and facilitates easy installation and removal.
Resilient Seating: Most wafer concentric butterfly valves come with resilient seat materials such as EPDM or NBR, which provide excellent sealing properties and resistance to wear, corrosion, and chemicals.
Bidirectional Sealing: The concentric design allows for bidirectional sealing, meaning the valve can be installed in either direction without affecting its performance.
Manual or Actuated Operation: Wafer concentric butterfly valves are available in manual or actuated configurations. Manual valves are operated by hand, while actuated valves can be controlled remotely using pneumatic, electric, or hydraulic actuators for automated flow control.

Selection Considerations:

Size and Pressure Rating: Choose a valve size and pressure rating suitable for the intended application and operating conditions. Consider factors such as flow rate, system pressure, and compatibility with existing piping.
Material Construction: Select valve materials compatible with the fluid being handled and the environmental conditions. Common materials include stainless steel, carbon steel, ductile iron, and various alloys.
Seat Material: Consider the type of seat material (e.g., EPDM, NBR, PTFE) based on the fluid properties (e.g., temperature, viscosity, chemical compatibility) and sealing requirements.
Operation Type: Decide whether manual or actuated operation is preferred based on the level of automation required, accessibility, and control system integration.
Standards Compliance: Ensure the selected valve complies with relevant industry standards and certifications for quality, performance, and safety, such as ANSI, API, ISO, and marine classification societies’ requirements.

Usage:

Installation: Properly install the wafer concentric butterfly valve between flanges using appropriate gaskets and fasteners according to manufacturer specifications and industry standards.
Operation: Operate the valve manually or remotely using the designated controls, following established procedures for opening, closing, and adjusting the flow as needed.
Maintenance: Implement a regular maintenance schedule to inspect, clean, lubricate, and replace components as necessary to ensure optimal performance and longevity.
Monitoring: Periodically monitor the valve’s operation and condition for signs of leakage, wear, or malfunction, and take corrective action as required to prevent downtime or safety hazards.
Emergency Response: Establish protocols for responding to valve failures, leaks, or other emergencies, including shutdown procedures, isolation measures, and contingency plans to mitigate risks and minimize disruptions.

By considering these factors and following best practices for selection, installation, and maintenance, wafer concentric butterfly valves can effectively control flow and provide reliable performance in marine applications and other industrial settings.

Valve material and valve standards-(1)

August 26, 2020

What material is WCB/LCB/LCC/WC6/WC in the valve?
W, wrought casting; C, Carbon steel; A, B, C indicate the strength value of steel grades from low to high.

lug type butterfly valve-ductile iron

WCA, WCA, WCC represent carbon steel, ABC represents the strength level, and WCB is commonly used. The corresponding pipe material of WCB should be A106B, and the corresponding forging material should be A105.
WC6 is an alloy steel casting, the corresponding pipe material is about A355 P11, and the forging is A182 F11; there is also WC9, high temperature resistant alloy steel, the corresponding pipe material is about A355 P22, and the corresponding forging is A182 F22.
WC: weldable casting
LCB/LCC (ASTM A352) low temperature carbon steel
ITCS is carbon steel with impact toughness; impact test C=carbon S=steel (A350)
Split body split type, side entry side mounted (referring to the actuator), corresponding to TOP entry top mounted type

Commonly used valve casting and forging carbon steel material table

material	country	standard	material grade name
Casting	China	GB/T 12229	WCA	WCB	WCC
			ZG205-415	ZG250-485	ZG275-485
	USA	ASTM A216/A216M	WCA	WCB	WCC
			UNS J02502	UNS J03002	UNS J02503
Forged	China	GB/T 12228 GB/T 699	25 25Mn 35 40 A105
	USA	ASTM A105/A105M	A105

Low temperature casting parts material name and temperature range

C	C	C-Mn	C-Mo	2.5Ni	Ni-Cr-Mo	3.5Ni	4.5Ni	9Ni	Cr-Ni-Mo
LCA	LCB	LCC	LC1	LC2	LC2-1	LC3	LC4	LC9	CA6NM
J02504	J03303	J02505	J12522	J22500	j42215	j31550	j41500	j31300	j91540
-32	-46	-46	-59	-73	-73	-101	-115	-115	-73

Commonly used valve ASTM Casting and Forged material sheet (ASME B16.5)

ASTM Casting	ASTM Forged	China name	Temp °C	suitable medium
Carbon steel
A216 WCB	A105	20	-29/427	water,steam,air,petroleum products
Low temp Carbon steel
A352 LCB	A350 LF2	16Mn	-46/343
A352 LCC	A350 LF2	16Mn	-46/343
High temp alloy
A217 WC1	A182 F1	20MnMo	-29/454	High temp, High pressure medium
A217 WC6	A182 F11	15CrMo	-29/552	High temp, High pressure medium
A217 WC9	A182 F22	10Cr2Mo1	-29/593	High temp, High pressure medium
A217 C5	A182 F5	1Cr5Mo	-29/650	Corrosive high temperature medium
A217 C12	A182 F9	Cr9Mo1	-29/593	High sulfur oxidizing medium
Martensitic stainless steel
A217 CA15	A182 F6a	Cr9Mo1	-29/593	High sulfur oxidizing medium
Austenitic stainless steel（C≤0.08）
A351 CF8	A182 F304	0Cr18Ni9	-196/537	corrosive medium
A351 CF3	A182 F304L		-196/425	corrosive medium
A351 CF8M	A182 F316	0Cr18Ni12Mo2Ti	-196/537	corrosive medium
A351 CF3M	A182 F316L		-196/425	corrosive medium
low carbon Austenitic stainless steel（C≤0.03）
A351 CF3	A182 F304L	00Cr18Ni10	-0.459016393	corrosive medium
A351 CF3M	A182 F316L	00Cr18Ni14Mo2	-196/454	corrosive medium
Special alloy
A351 CN7M	B462Gr.NO8020 (ALLOY20)		-29/149	Oxidizing medium and various concentrations of sulfuric acid
A494 M-30C (Monel alloy)	B4564 Gr.NO4400		-29/482	Hydrofluoric acid, Sea water
Hastelloy H.B H.C				Strong corrosive medium such as dilute sulfuric acid

Notes:
1. Forged valve body material is dense, not easy to have defects, the structure size is not limited by the mold, and the pressure bearing performance is reliable. It is mostly used for high pressure, oxygen working conditions, small diameter or other small batch valve manufacturing, generally at high temperature, Choose forgings under high pressure or low temperature or special medium; castings are generally only suitable for medium and low pressure, and are mostly used for mass production of standardized molded valves.

2. The difference between material A351 CF3M and A182 F316L: the materials corresponding to the two standards are 316 stainless steel. CF3M stands for castings and is often used as valve material. The corresponding forging steel code is A182 F316L. ASTM A216 WCB is a casting, and its forging is A105; the casting of SS304 is A351-CF8, and the forging is A182-F304.

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>.