A Double Block and Bleed (DBB) valve is a type of valve assembly that provides two block valves and a bleed (vent) valve within a single compact unit. This design is used to achieve positive isolation in critical applications where the prevention of fluid leakage is crucial. The primary purpose of a Double Block and Bleed valve is to ensure that both upstream and downstream flow paths are blocked off before any maintenance or repair work is performed on the system. Here's how a Double Block and Bleed valve typically works: Blocking Function 1. First Block Valve (Isolation Valve 1): The upstream flow is blocked by closing the first block valve. This prevents the fluid from flowing into the downstream section of the pipeline. 2. Bleed (Vent) Valve: Once the first block valve is closed, the bleed valve is opened. This allows any trapped fluid between the first and second block valves to be safely vented or bled off, reducing the pressure in the isolated section. 3. Second Block Valve (Isolation Valve 2): With the bleed valve open, the second block valve can be closed to block the downstream flow. Now, both the upstream and downstream flow paths are isolated from each other. Verification and Maintenance 1. The operator can verify the isolation by checking pressure gauges or indicators to ensure that both block valves are closed and the bleed valve is open. 2. Maintenance or repair work can be performed on the equipment or pipeline between the block valves without the risk of fluid leakage. Opening the System 1. When the maintenance work is completed and it's safe to resume operation, the second block valve is opened. 2. The bleed valve is then closed to allow normal flow to resume. The Double Block and Bleed valve design provides an extra layer of safety by offering redundancy in blocking fluid flow and providing a means to safely vent any residual fluid. It is commonly used in industries such as oil and gas, petrochemicals, and other applications where fluid containment and safety are critical considerations.

In today's highly industrialized and technological era, various advanced valve technologies are constantly emerging, among which three-way ball valves, as a multifunctional and efficient pipeline control equipment, are gradually becoming indispensable in industrial processes. Three-way ball valve is a uniquely designed valve with three channels that can achieve multi-directional fluid control. Its structure consists of a sphere and a valve body, which switches between different channels by rotating the sphere, thereby flexibly controlling the flow direction of the fluid. This design enables the widespread application of three-way ball valves in complex industrial processes. Features and Advantages 1. Multi channel design: The unique design of the three-way ball valve allows for the simultaneous connection of multiple pipelines, achieving integration and coordination of complex systems. This allows users to switch between multiple fluid channels in a single valve operation, improving the efficiency of industrial processes. 2. High pressure and high temperature resistance: Due to the excellent selection of manufacturing materials, three-way ball valves are often able to withstand high pressure and high temperature environments. This enables it to operate stably under some harsh industrial conditions, ensuring the safety and reliability of the system. 3. Compact structure: Compared to other types of valves, three-way ball valves usually have a more compact structure. This not only saves installation space, but also helps to reduce the operating costs of the system. 4. Easy to operate: The operation of the three-way ball valve is relatively simple, and fluid channel switching can be achieved by rotating the operation. This enables staff to quickly and accurately regulate the system. 5. Multipurpose applications: Due to its flexible design, three-way ball valves are widely used in fields such as chemical, petroleum, and pharmaceuticals. It is not only suitable for ordinary liquid pipelines, but also for handling corrosive media and working environments under high temperature and pressure conditions. With the continuous progress of industrial technology, the design and application of three-way ball valves will usher in more innovation. In the future, we can expect to see the emergence of more intelligent and automated three-way ball valves, providing more possibilities for automatic control and optimization of industrial processes. Three-way ball valves will continue to play an irreplaceable role in the industrial field, promoting the development of industrial processes towards greater efficiency and sustainability.

Butterfly valve is a structurally simple regulating valve that can be used for switch control of low-pressure pipeline media. The structural length and overall height of butterfly valves are small, with fast opening and closing speeds, and good fluid control characteristics. The structural principle of butterfly valves is most suitable for making large-diameter valves. When using butterfly valves for flow control, the most important thing is to choose the correct size and type of butterfly valve so that it can work properly and effectively. 1. Due to the relatively large pressure loss of butterfly valves compared to gate valves and ball valves, they are suitable for pipeline systems with less stringent pressure loss requirements. 2. Since butterfly valves can be used for flow regulation, they are suitable for use in pipelines that require flow regulation. 3. Due to the limitations of the structure and sealing materials of butterfly valves, they are not suitable for use in high-temperature and high-pressure pipeline systems. The general working temperature is below 425 ℃, and the nominal pressure is below PN100. 4. Due to the short length of the butterfly valve structure and its ability to be made into a large diameter, it is advisable to choose a butterfly valve in situations where the structural length is required to be short or for large diameter valves (such as DN1000 and above). 5. Due to the fact that butterfly valves can be opened or closed by only rotating 90 °, it is advisable to choose butterfly valves in areas with fast opening and closing requirements.

A swing check valve is a check valve in which the valve disc rotates around the rocker shaft in the body cavity. The opening and closing principle of a swing check valve is the same as that of a lift check valve, which also relies on the action of fluid pressure and the self weight of the valve disc to act on its own. The difference is that the opening and closing method of the valve disc is rotational motion rather than upward and downward movement, and the inlet direction of the fluid should be on the side that can impact the rotation of the valve disc. The closing component of a swing check valve is a valve disc or disc that is equivalent to the diameter of the pipeline, suspended inside the valve chamber. When the fluid flows forward, the valve disc opens under the action of fluid pressure, and when the pressure drops, the valve disc closes under the action of its own weight and the pressure of the countercurrent fluid. A swing check valve consists of a valve body, valve cover, valve disc, and rocker. The valve disc is in a circular shape and rotates around the pin axis outside the valve seat channel. The internal channel of the valve is streamlined, and the flow resistance is smaller than that of the straight through lifting check valve, making it suitable for large-diameter pipelines. But at low pressure, its sealing performance is not as good as the lift check valve. To improve sealing performance, auxiliary springs or heavy hammer structures can be used to assist sealing. Due to the weight of the valve disc, when a swing check valve opens, there is relatively greater resistance to the fluid. In addition, due to the valve disc being suspended in the fluid, it can cause turbulence in the fluid. This also indicates that the fluid pressure drop through swing check valves is greater than that through other forms of check valves. When the flow direction suddenly changes, the valve disc will fiercely close on the valve seat, causing significant wear on the valve seat and generating water hammer along the pipeline. To overcome this problem, a damping device can be installed on the valve disc and a metal seat can be used to reduce seat wear. According to the number of valve discs, swing check valves can be divided into three types: single disc, double disc, and multi disc. 1. Single disc type has only one seat channel and one disc, suitable for medium caliber swing check valves. 2. The double disc type has two valve discs and two seat channels, suitable for larger diameter swing check valves. 3. For large-diameter check valves, if a single disc structure is used, significant hydraulic impact will inevitably occur when the medium flows in the opposite direction, and even damage to the sealing surfaces of the valve disc and valve seat will be caused. Therefore, a multi disc structure is adopted. Its opening and closing components are composed of many small diameter valve discs. When the medium stops flowing or flows back, these small valve discs wil...

As a component used to achieve on/off and flow control in pipeline systems, electric butterfly valves are becoming increasingly popular in practical applications due to their excellent quality and performance! Electric butterfly valves can generally be divided into the most common types of electric clamp butterfly valves and electric flange butterfly valves according to their different connection methods. There are two types of sealing materials: soft sealing (normal temperature and pressure) and hard sealing (high temperature and high pressure). Working Principle Electric butterfly valves use electricity as the driving force. After adjusting the connection between the electric actuator and the valve stem and adjusting the electric butterfly valve, the electric seal is used as the driving force to drive the 0-90 ° rotation movement of the hard sealed butterfly valve plate. The electric butterfly valve receives 4-20mA industrial automation control system signals to accurately control the valve opening, thereby achieving the adjustment and control of different process parameters such as flow rate, temperature, and pressure. Installation Precautions (1) Electric butterfly valves should be installed vertically on horizontal pipelines. If there is a need for horizontally inclined equipment in special circumstances, support should generally be added. (2) The equipment location should have good environmental conditions, and the ambient temperature should be between -25 to +55 ℃. (3) Try to prevent equipment from being exposed to vibration sources, otherwise necessary anti vibration reinforcement measures should be taken. (4) When installing equipment, it is necessary to point the arrow direction on the valve body or flange towards the direction of the medium. (5) Before installing the equipment, it is necessary to carefully remove welding slag and other debris inside the pipeline. After installing the equipment, the valve core should be at a larger opening and the pipeline and butterfly valve should be cleaned again to prevent debris from getting stuck and damaging the saving parts. (6) Electric butterfly valves should be located in a position that is easy to maintain and repair. (7) The straight pipe section in front of the valve should be as long as possible. (8) Export piping should use straight pipe sections with a diameter of 3-5 times the pipeline diameter.

1. Leakage at the packing of butterfly valve Faults: (1) The filler has exceeded its usage period and has aged. (2) Excessive force during operation. (3) The live bolt is not tightened. Solutions: (1) Aging or damaged fillers should be replaced in a timely manner. (2) It should be operated uniformly with normal force, and no casing or other methods should be added. (3) Evenly tighten the bolts that hold down the packing. 2. Leakage at sealing surface of butterfly valve Faults: (1) The installation direction of the valve does not match the flow direction of the medium. (2) The butterfly valve does not close properly. (3) The butterfly valve that has been closed for a long time has accumulated scale on the sealing surface. (4) The sealing surface is severely damaged. Solutions: (1) Pay attention to installation inspection and ensure that it is tightly closed in place. (2) Open a gap in the valve and allow the high-speed fluid to flush away any dirt on the seal. (3) Re grind and thicken the adjusting gasket for compensation. 3. Leakage at the flange connection of butterfly valve Faults: (1) Uneven tightening force of bolts. (2) Aging and damage of gaskets. (3) The material used for the gasket does not meet the requirements of the working medium. Solutions: (1) Tighten the bolts evenly again. (2) Replace the gasket in a timely manner. (3) Select gasket materials and forms correctly according to the requirements of the working conditions. 4. Damaged at handle and handwheel of butterfly valve Faults: (1) Incorrect use. (2) Loose fasteners. (3) Damage to the connection between the handle, handwheel, and valve stem. Solutions: (1) Prohibit the use of pipe pliers, long levers, impact tools, etc. (2) Repair and repair at any time. 5. Jamming at worm gear drive of butterfly valve Faults: (1) Unclean embedded dirt, affecting lubrication. (2) Poor operation. Solutions: (1) Please keep it clean and refuel regularly. (2) If a bite is found during operation and there is significant resistance, the operation cannot continue, otherwise the damage will worsen. 6. Electric installation fault of butterfly valve Faults: (1) Poor lubrication, foreign objects stuck inside the valve causing excessive torque. (2) Motor malfunction. Solutions: (1) Oil should be added and kept clean to ensure that the oil pipe is in good condition, the packing is moderately compressed, and foreign objects are promptly removed. (2) The working time of the motor should not exceed 15 minutes, and the power supply should be normal. It should be avoided to touch and get damp.