The scope of application of floating ball valve： The floating ball valve is the initial structure of the development of the ball valve, this structure is characterized by the media pushing the ball, and squeezing on the seal seat to obtain a reliable seal, the media force is proportional to the square of the valve diameter, so when the diameter increases, the pressure level increases, the media force will be large, for example, Class300, NPS 8 floating ball valve, the media force acting on the seat is about 190kN, which will make the seal seat on the This will cause the contact stress on the seal seat to approach the allowable specific pressure of the material and increase the operating torque exponentially. Therefore, the floating ball valve is suitable for NPS 8 or less, pressure class 150, class 300, and class 600 for small diameter NPS2 or less. Floating ball valve installation and maintenance guidelines： (1) Precautions For safety, the following must be observed before the valve is removed or disassembled from the pipeline. ①When disassembling the valve, hands must not touch the inner cavity of the valve. Remotely operated valves can be closed at any time and hurt...
What is floating type ball valve? Floating ball valves can be divided into two categories: side-mounted body and top-mounted body according to the structural form of the valve body. The side-mounted valve body can be divided into integral, two-piece, and three-piece types. No matter what kind of structure, they must meet some basic principles. The basic principles that must be met by a floating ball valve are as follows： ①Stem should be installed backward, anti-blowout structure. This is ANSIB16.34 section 6.5.1.1, the structure of the valve stem should not rely on the packing gland fasteners to limit its position, to be precise, in the valve under pressure, the stem will not be due to the release of the stem sealing fasteners from the valve. This is the basic condition that must be ensured from the perspective of the safe use of the valve. ② anti-static structure is composed of a stainless steel ball and a spring, a group placed in the hole at the end of the stem to maintain contact with the ball; another group placed on the cylinder of the stem to maintain contact with the valve body so that the possible static electricity generated from the valve...
1. Fixed ball valve sealing principle The opening and closing parts of the fixed ball valve is a sphere with two support shafts, with a channel in the middle equal to the diameter of the pipe, with two floating seats on both sides, the sphere does not deviate from the axis of the support shaft on the sphere when the sphere is turned, the support shaft is supported by the upper and lower two sliding bearings, the seat is floating, under the action of medium force, pushing the sphere to produce a contact stress to obtain a reliable seal. Like the floating ball valve, the valve swings 90° from open to close, or from close to open. 2. Fixed ball valve structural features Fixed ball valve body consists of the main body, left and right two sub-body, the ball is a journal at the upper end, the lower end has a shaft hole of the ball, the upper part of the body has a stuffing box, and the ball journal is connected to a sliding bearing, the lower end of the ball has a shaft hole, equipped with a sliding shaft bearing sleeve, the bottom of the valve body...
1. Fixed ball valve ,ball body: The most important feature of the fixed ball valve is that the ball does not deviate from the center of rotation of the ball during the switching process. Three types of structure: ①As shown in the figure, the upper part of the ball has a shaft shank, and the lower part is a shaft hole for a fixed shaft to be inserted, the structure of the ball is a shaft and a hole structure. ② As shown in figures (a) and (b), the sphere is two upper and lower shaft holes, respectively inserted by the upper and lower shafts. The structure shown in figure (a) is suitable for small diameter, the insertion depth of the shaft hole in the sphere is short and can only withstand a small-medium force, the structure shown in figure (b) is suitable for large diameter and can withstand a larger medium force, and the support journal and drive shaft are separated, the drive shaft only withstands the action of torque. ③ As shown in Figure (c), the ball is two outreach shafts, vertical upper and lower two support plates, the media force through the journal and support plate transferred...
Floating ball valve sealing principle. Floating ball valve opening and closing parts is a sphere, the middle of a through-hole equal to the diameter of the pipeline, the inlet and outlet ends are placed in a PTFE seal seat, and is contained in a metal valve body, when the hole in the ball and the pipeline channel overlap, the valve is in the open state; when the hole in the ball and the pipeline channel vertical, the valve is in the closed state. Valve from open to close, or from close to open ball rotation 90 ° angle of travel. Floating ball valve sealing principle When the ball valve is in the closed position, the media pressure at the inlet end acts on the ball, resulting in a force that pushes the ball, so that the ball presses against the seal seat at the outlet end, resulting in contact stress on the conical surface of the seal seat, forming a contact zone, the contact zone unit area of The force per unit area of the contact zone is called the working pressure q of the valve seal, and when this pressure is greater than the pressure necessary for...
Overview of ball valves： The ball valve was introduced after the Second World War, although its invention can be traced back to the early 20th century, this structure patent due to the limitations of the materials industry and mechanical processing industry at that time failed to complete its commercialization steps. In 1943, DuPont invented a polymer material polytetrafluoroethylene (PTFE) plastic, this material has sufficient tensile and compressive strength, a certain elasticity, good self-lubricating properties, and excellent corrosion resistance, is very suitable as a sealing material, can obtain a very reliable sealing effect. On the other hand, due to the progress of the ball turning machine and ball grinding machine, it is possible to process the ball with high roundness and surface finish as the opening and closing parts of the ball valve. In this way, a full diameter, 90 ° angle stroke rotary valve new species into the valve market, attracting widespread attention, and gradually replacing the traditional valve products globe valve, gate valve, plug valve, and butterfly valve, and constantly expanding its application areas, from small diameter to large diameter, from low to high pressure, from room temperature to high temperature, to low temperature. At present, the maximum...
What is a plug valve? The plug valve is a valve whose opening and closing member (plug) is driven by the valve stem and rotates around the axis of the valve stem. The plug valve is the first type of valve used by people to shut off flow. The opening and closing of the valve are completed by rotating 90 ° to connect or disconnect the passage port on the plug and the passage port on the valve body. The plug valve is most suitable for shutting off the medium and dividing the flow. However, according to the nature of use and the erosion resistance of the sealing surface, it can be used in throttling conditions through special structural design and changing the shape of the channel of the plug. Because the movement between the sealing surfaces of the plug valve has a wiping effect, and can completely prevent contact with the flowing medium at the full start, it can usually also be used for medium with suspended particles. The characteristics and structure of the plug valve One: the advantages and disadvantages of the plug valve (1) Advantages of plug valve ①Simple structure, few parts, small size and...
What are the output signals of the electromagnetic flowmeters? The output signal of the electromagnetic flowmeter is not single and constant. Under normal circumstances, the electromagnetic flowmeter outputs 4~20mA and sends it to the system for display, or enters the secondary meter for display. This signal is used to display the instantaneous flow. If the flow at this point needs to be accumulated in the system or in the secondary table, then the pulse signal is used. A pulse signal will correspond to a certain flow value, and then be superimposed in the system to calculate the cumulative flow. Such two signals will not interfere with each other. Generally, the pulse output mode of electromagnetic flowmeter is mainly used for measurement mode, outputting a pulse, representing an equivalent flow, such as 1L or 1M3. Pulse output equivalent divided into: 0.001L, 0.01L, 0.1L, 1L, 0.001 M3, 0.01 M3, 0.1 M3, 1 M3; ,0.001UKG, 0.01UKG, 0.1UKG, 1UKG, 0.001USG, 0.01USG, 0.1USG, 1USG . Therefore, when customers choose the pulse equivalent, they need to pay attention to observe whether the flow range of the flowmeter matches the pulse equivalent. For volume flow, the calculation formula is: QL=0.0007854×D2×V (L/S) or QM=0.0007854×D2×V×10-3 (M3/S) Among them, D...
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