Views: 0 Author: Site Editor Publish Time: 2024-01-25 Origin: Site
Invented in the mid-20th century, the butterfly valve swiftly gained popularity due to its simplicity and versatility. It's designed to regulate or isolate the flow of various types of fluid, including but not limited to liquid, gas, or slurry. This function is facilitated by a disc that is mounted on a rotating shaft. When the butterfly valve is fully opened, the disc pivots out of the pathway to allow the fluid to flow. Conversely, the flow ceases when the disc obstructs the fluid’s passage.
The butterfly valve primarily works by employing the use of a disk that would obstruct the flow of the fluid. This is facilitated by the actuator, which turns the stem and subsequently the disk. A quarter turn would fully open the valve while a full turn in the opposite direction would instigate a full stop to the fluid flow.
Various types of butterfly valves have been designed and manufactured to cater to different functional areas and complexities, such as:
1.Concentric Butterfly Valves: These are the simplest and most common type of butterfly valves with a resilient rubber seat and a metal disc. Due to their simple design, they are typically used in low-pressure and temperature applications.
2.Double-eccentric Butterfly Valves: Also known as high-performance butterfly valves, these feature an offset stem and disc arrangement where the stem is located behind the disc to allow it to move away from the valve seal reducing wear and tear. They're typically used in higher pressure systems and where tighter seals are necessary.
3.Triple-eccentric Butterfly Valves (Triple Offset Butterfly Valves): In these types of valves, the disc and shaft are offset which allows for almost no wearing on the valve seat. They’re often used in high-pressure and high-temperature applications where bubble-tight shutoff is required and in cryogenic services.
4.Wafer Style Butterfly Valves: These are thinner valves that fit between two pipeline flanges. They're cost-effective and space-efficient, making them popular for a variety of uses, particularly where weight and space are considerations.
5.Lug Style Butterfly Valves: Unlike wafer style, lug-style valves have threaded inserts at both sides of the valve body. This allows them to be installed into a system using two sets of bolts and nuts. They are installed between two flanges using a separate set of bolts for each flange.
6.Inflatable Seated Butterfly Valves: These are basically used for air blower or vacuum appications along with some dry bulk material handling applications. They consist of a durable fabric-reinforced elastomer seat installed in the body bore, and inflated against the gate to supply the seating pressure.
7.Rotary Valve (quarter-turn valves): Butterfly valves are also considered as rotary valves as they use the rotational motion process to allow, block and regulate the flow. The operation is similar to that of a ball valve.
8.Lined Butterfly Valves: They are used for corrosive services; many applications like oil, solvents, caustics, vacuum services etc. These valves have excellent corrosive protection capability.
Butterfly valves can be actuated using various methods, each with its own benefits depending on the application. Here are the main types of actuation methods:
1.Manual Actuation: The simplest form of actuation, manual actuation involves the use of a hand wheel or lever attached to the valve stem. When the wheel or lever is turned by hand, it rotates the disc, opening or closing the valve.
2.Electrical Actuation: Electrically actuated butterfly valves use an electric motor to open or close the valve. The motor operates the valve stem through a series of gears. These types of valves are often used in applications where manual operation isn't practical due to the scale, complexity, or location of the system.
3.Pneumatic Actuation: Pneumatic actuators use air pressure to operate the valve. When the air pressure is applied, the actuator rotates the valve stem, thus opening or closing the valve. These models are typically used in industries with extensive compressed air systems.
4.Hydraulic Actuation: Hydraulic actuators work similarly to pneumatic actuators, but they use hydraulic fluid instead of air pressure. This method of actuation is effective for heavy-duty or high-pressure applications where significant force is required to operate the valve.
5.Electro-hydraulic Actuation: These types of actuators use an electric motor to provide the mechanical energy that powers a hydraulic pump that, in turn, drives the actuator.
6.Solenoid Actuation: Mostly used in conjunction with hydraulic or pneumatic actuation, a solenoid is an electromagnetic coil that, when energized, produces a magnetic field that operates the actuator.
7.Thermal Actuation: In this method, the temperature changes in the environment lead to the changes in valve position. It's not common and usually applied for specific cases.
Choosing the right actuation method depends on a variety of factors, including the specific needs of the process, the operating environment, safety requirements, and lifecycle costs.
Butterfly Valve Wiring predominantly depends on the type of actuator used in the butterfly valve assembly. In most cases, butterfly valves use either an electric or pneumatic actuator. Here's a rough guide on how they are wired:
1.Electric Actuator Wiring:
Electric actuators are commonly wired in the Open/Close control circuit for butterfly valves. For doing this, you will require a single phase supply voltage (commonly 24V, 120V, or 240V) depending on the actuator's rating. This wiring powers the motor inside the actuator.
In a simple scenario, an electric actuator will have three terminals:
●Common: This terminal will be connected to one side of the power source.
●Open: This terminal, when connected to the other side of the power source, will open the valve.
●Close: Similarly, this terminal, when energized, will close the valve.
The power can be switched between Open and Close terminals to control the valve's position. Make sure the valve does not receive the 'Open' and 'Close' signals simultaneously.
2.Pneumatic Actuator Wiring:
Pneumatic butterfly valve involves the use of a solenoid valve. Solenoid valves are electrically operated and control the airflow into the pneumatic actuator, which in turn, rotates the butterfly valve disc.
For a 2-way solenoid valve:
●Connect the positive terminal of your power source (DC or AC depending on the solenoid) to one terminal of the solenoid coil.
●Connect the other terminal of the coil to the negative/Neutral of your power source.
When the solenoid is energized, the airflow routes inside the actuator causing it to open or close. In the event of power failure, a spring inside the actuator returns it to a safe position (either fully open or fully closed).
Please note, for all electrical wiring, appropriate electrical protection and isolation should be put in place to prevent accidental electrocution. Consulting with a qualified electrician or control engineer is strongly recommended. Moreover, all installations should comply with local and state electrical and building codes.
1.Water and Wastewater Treatment: Butterfly valves are instrumental in these industries concerning the control of water and wastewater flow. Their reliability, coupled with their capacity to handle large flow rates and withstand harsh operating conditions, makes them an attractive choice for slurry and water treatment services. For instance, butterfly valves can be found in filtration units, where they regulate the inflow or outflow of water.
2.HVAC: In heating, ventilation, and air-conditioning systems, butterfly valves control the flow of air and water. Due to their cost-effectiveness and strong shutoff capabilities, they're often chosen for air conditioning systems and cooling towers. From the regulation of chilled water to the control of hot airflow for heating, butterfly valves prove their versatility in HVAC applications.
3.Power Generation: Butterfly valves are well-suited for use in power plants because of their ability to handle high-pressure and high-temperature conditions. They can be found in cooling water systems, feed water systems, and condensate systems. For example, butterfly valves control the flow of condensate water to help regulate turbine output in electricity generation.
4.Oil and Gas Industry: In the demanding environments of oil and gas industries, butterfly valves excel. They are employed for isolating and throttling purposes. They offer excellent sealing when it comes to isolating portions of the pipeline during maintenance or emergencies. In the throttling scenario, they can regulate the flow of crude oil and gases during extraction processes.
5.Chemical Industry: Butterfly valves are used in the chemical industry where aggressive and corrosive substances often require resilient, durable butterfly valves. They come in handy to isolate and regulate the flow of different aggressive chemicals during multiple stages of chemical processing.
6.Pharmaceutical and Food & Beverage Industries: In hygienic industries such as pharmaceuticals and food & beverage, butterfly valves are used because they can be easily cleaned and have minimal dead space. They're useful in controlling the flow of liquids during various stages of production, from the transportation of raw ingredients to the final product handling.
7.Pulp and Paper Industry: In the pulp and paper industry, butterfly valves are used to handle everything from water to 99% sulfuric acid throughout the pulping process. They are chosen for their ability to handle fibrous slurries efficiently.
