Brian Nesbitt is a well-known consultant with a considerable publishing record. Handbook Of Valves And Actuators. Valves, Handbook of Valves and Actuators. It is packed with useful information, illustration and table and covers all aspects of Brian Nesbitt is a well-known consultant with a considerable publishing record. Brian Nesbitt. Release on by Butterworth-Heinemann, this book has page count that consist of essential Handbook of Valves and Actuators by Brian Nesbitt.
Download Handbook of Valves and Actuators. All Categories kiwibackup Related Books. E-bok, Laddas ned direkt. Nesbitt B. The basic type of ball valve requires a quarter turn from the fully open to the fully closed position. The valve can be operated by means of a lever, which also serves as an open or shut indicator, or by the use of an automatic actuator. The spherical plug not only gives precise control of the flow through the valve, but also gives a tight shutoff when in the closed position.
The valves are designed so that no internal lubrication is required and the torque required to rotate the ball is negligible. The ball and stem are generally machined from one piece. For larger sizes and higher pressure ratings, the ball is constructed with a double stem and is supported by bearings. This construction requires a seal for one end and a packing box for the opposite end. Figure 8 Manual-Automatic Positioning. Ball valves are suitable for handling slurries and fluids with a high solid content, and for this reason have found wide applications in the paper industry, chemical plants, and sewage treatment plants.
The plug valve, shown in Fig. The plug valve consists of a tapered or straight cylinder containing a hole, which is inserted into the cavity of the valve body. The hole in the plug lines up with the axis and opening in the valve body.
The valve has a tapered plug which is secured in the valve body by the valve cover. A packing box is recessed in this cover, with packing held in place by the gland, thus preventing leakage along the valve stem. The tapered plug has a tendency to jam in the tapered seat and can cause scoring if forced to turn.
Most plug valves are lubricated to eliminate this problem. The lubricant is supplied through the center of the stem and is distributed through channels to the seating surfaces. Other valves are equipped with a flexible, smooth liner which eliminates the need for lubrication. The pressure drop across this valve when it is in the wide open position is very low. This type of valve is self-cleaning. Plug valves are used as quick opening valves in gas supply lines, low pressure steam lines, water treatment plants, pulp and paper, and chemical industries.
The check valve, shown in Fig. The flow of fluid keeps the check valve open while gravity and reversal of flow will cause the valve to close. The two basic types of check valves are the swing check and the lift check.
The swing check valve features an almost straight line flow, and therefore offers little resistance to flow. The disc, which is hinged at the top, swings freely in an arc from the fully closed to the fully open position. The flow through the lift check valve undergoes two changes in direction as it passes through a horizontal section upon which the disc seats. The disc moves upward to allow the fluid to pass through and moves downward to close if the flow should reverse. A dashpot is used to cushion the action of the disc in this design.
Skip to content Valves. Gate Valves The gate valve, shown in Fig. Figure 6 Ball Valve The spherical plug not only gives precise control of the flow through the valve, but also gives a tight shutoff when in the closed position. Figure 7 V Ball Valve Fig. Figure 8 Manual-Automatic Positioning Ball valves are suitable for handling slurries and fluids with a high solid content, and for this reason have found wide applications in the paper industry, chemical plants, and sewage treatment plants.
Plug Valves The plug valve, shown in Fig. Figure 9 Plug Valve The tapered plug has a tendency to jam in the tapered seat and can cause scoring if forced to turn. Check Valves The check valve, shown in Fig. Figure 10 Swing Check Valve Figure 11 Lift Check Valve The swing check valve features an almost straight line flow, and therefore offers little resistance to flow.
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