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Butterfly Valves 2008-03-06 02:17:52 Butterfly Valves
A butterfly valve, illustrated in Figure 19, is a rotary motion valve that is used to stop, regulate, and start fluid flow. Butterfly valves are easily and quickly operated because a 90o rotation of the handle moves the disk from a fully closed to fully opened position. Larger butterfly valves are actuated by handwheels [...] Read more:Butterfly
Pinch Valves 2008-03-06 02:11:50 Pinch Valves
The relatively inexpensive pinch valve, illustrated in Figure 18, is the simplest in any valve design. It is simply an industrial version of the pinch cock used in the laboratory to control the flow of fluids through rubber tubing. Pinch valves are suitable for on-off and throttling services. However, the effective throttling range is [...]
Reducing Valves 2008-03-06 00:54:00 Reducing Valves
Reducing valves automatically reduce supply pressure to a preselected pressure as long as the supply pressure is at least as high as the selected pressure. As illustrated in Figure 16, the principal parts of the reducing valve are the main valve; an upward-seating valve that has a piston on top of its valve stem, [...] Read more:Reducing
Diaphragm Construction 2008-03-05 22:40:38 Diaphragm Construction
The operating mechanism of a diaphragm valve is not exposed to the media within the pipeline. Sticky or viscous fluids cannot get into the bonnet to interfere with the operating mechanism. Many fluids that would clog, corrode, or gum up the working parts of most other types of valves will pass through a [...]
Diaphragm Valves 2008-03-05 22:36:55 Diaphragm Valves
Diaphragm valve is a linear motion valve that is used to start, regulate, and stop fluid flow.
The name is derived from its flexible disk, which mates with a seat located in the open area at the top of the valve body to form a seal. A diaphragm valve is illustrated in Figure 14.
Diaphragm valves [...]
Manually Operated Plug Valve Installation 2008-03-05 22:35:08 Manually Operated Plug ValveInstallation
When installing plug valves, care should be taken to allow room for the operation of the handle, lever, or wrench. The manual operator is usually longer than the valve, and it rotates to a position parallel to the pipe from a position 90° to the pipe.
Plug Valve Glands
The gland of the [...]
Lubricated Plug Valve Design 2008-03-05 22:33:51 Lubricated Plug Valve
Design
Clearances and leakage prevention are the chief considerations in plug valves. Many plug valves are of all metal construction. In these versions, the narrow gap around the plug can allow leakage. If the gap is reduced by sinking the taper plug deeper into the body, actuation torque climbs rapidly and galling can [...]
Plug Valve Ports 2008-03-05 22:31:07 Plug Ports
An important characteristic of the plug valve is its easy adaptation to multiport construction. Multiport valves are widely used. Their installation simplifies piping, and they provide a more convenient operation than multiple gate valves. They also eliminate pipe fittings. The use of a multiport valve, depending upon the number of ports in the plug [...] Read more:Valve
Plug Valves 2008-03-05 22:27:49 Plug Valves
A plug valve is a rotational motion valve used to stop or start fluid flow. The name is derived from the shape of the disk, which resembles a plug. A plug valve is shown in Figure 13. The simplest form of a plug valve is the petcock. The body of a plug valve is [...]
Ball Valves 2008-03-05 06:40:33 Ball Valves
A ball valve is a rotational motion valve that uses a ball-shaped disk to stop or start fluid flow. The ball, shown in Figure 12, performs the same function as the disk in the globe valve. When the valve handle is turned to open the valve, the ball rotates to a point where the [...]
Globe Valve Disks 2008-03-05 06:37:10 Globe ValveDisks
Most globe valves use one of three basic disk designs: the ball disk, the composition disk, and the plug disk.
Ball Disk
The ball disk fits on a tapered, flat-surfaced seat. The ball disk design is used primarily in relatively low pressure and low temperature systems. It is capable of throttling flow, but is primarily [...] Read more:Globe
Angle Valve Design 2008-03-05 06:35:01 Angle Valve
Design
The angle body globe valve design, illustrated in Figure 11, is a simple modification of the basic globe valve. Having ends at right angles, the diaphragm can be a simple flat plate. Fluid is able to flow through with only a single 90° turn and discharge downward more symmetrically than the discharge from [...] Read more:Angle
Globe Valve Body Designs 2008-03-05 05:58:31 Globe Valve
Body Designs
The three primary body designs for globe valves are Z-body, Y-body, and Angle.
Z-Body Design
The simplest design and most common for water applications is the Z-body. The Z-body is illustrated in Figure 9. For this body design, the Z-shaped diaphragm or partition across the globular body contains the seat. The horizontal setting of [...] Read more:Globe
Globe Valves 2008-03-05 00:49:55 Globe Valves
A globe valve is a linear motion valve used to stop, start, and regulate fluid flow A Z-body globe valve is illustrated in Figure 9. As shown in Figure 9, the globe valve disk can be totally removed from the flowpath or it can completely close the flowpath. The essential principle of globe valve [...] Read more:Globe
Gate Valve Seat Design 2008-03-03 21:49:35 Gate Valve
Seat Design
Seats for gate valves are either provided integral with the valve body or in a seat ring type of construction. Seat ring construction provides seats which are either threaded into position or are pressed into position and seal welded to the valve body. The latter form of construction is recommended for higher [...]
Gate Valve Stem Design 2008-03-03 21:48:46 Gate Valve
Stem Design
Gate valves are classified as either rising stem or nonrising stem valves. For the nonrising stem gate valve, the stem is threaded on the lower end into the gate. As the hand wheel on the stem is rotated, the gate travels up or down the stem on the threads while the stem [...]
Gate Valve Disk Design : Parallel Disk 2008-03-03 21:47:03 Parallel Disk
The parallel disk gate valve illustrated in Figure 8 is designed to prevent valve binding due to thermal transients. This design is used in both low and high pressure applications.
The wedge surfaces between the parallel face disk halves are caused to press together under stem thrust and spread apart the disks to seal against [...] Read more:Parallel
, Valve
Gate Valve Disk Design 2008-03-03 21:43:14 Gate Valve
Disk Design
Gate valves are available with a variety of disks. Classification of gate valves is usually made by the type disk used: solid wedge, flexible wedge, split wedge, or parallel disk.
Solid wedges, flexible wedges, and split wedges are used in valves having inclined seats. Parallel disks are used in valves having parallel seats.
Regardless [...]
Gate Valves 2008-03-03 17:34:28 Gate Valves
A gate valve is a linear motion valve used to start or stop fluid flow; however, it does not regulate or throttle flow. The name gate is derived from the appearance of the disk in the flow stream. Figure 4 illustrates a gate valve.
The disk of a gate valve is completely removed from the [...]
Pressurizer 2008-03-08 22:51:59 Introduction
There are two types of pressurizers: static and dynamic. A static pressurizer is a partially filled tank with a required amount of gas pressure trapped in the void area. A dynamic pressurizer is a tank in which its saturated environment is controlled through use of heaters (to control temperature) and sprays (to control pressure).
This chapter [...]
Mixed-Bed Demineralizer 2008-03-08 22:10:13 Mixed-Bed Demineralizer
A mixed-bed demineralizer is a demineralizer in which the cation and anion resin beads are mixed together. In effect, it is equivalent to a number of two-step demineralizers in series. In a mixed-bed demineralizer, more impurities are replaced by hydrogen and hydroxyl ions, and the water that is produced is extremely pure. The [...] Read more:Mixed
Demineralizers 2008-03-08 22:01:24 Purpose of Demineralizers
Dissolved impurities in power plant fluid systems generate corrosion problems and decrease efficiency due to fouled heat transfer surfaces. Demineralization of the water is one of the most practical and common methods available to remove these dissolved impurities.
In the plant, demineralizers (also called ion-exchangers) are used to hold ion exchange resins [...]
Natural Convection Cooling Towers 2008-03-08 21:32:20 Natural Convection CoolingTowers
Natural convection cooling towers, illustrated in Figure 12, use the principle of convective flow to provide air circulation. As the air inside the tower is heated, it rises through the tower. This process draws more air in, creating a natural air flow to provide cooling of the water. The basin at the [...] Read more:Natural
Induced Draft Cooling Towers 2008-03-08 21:30:20 Induced DraftCoolingTowers
Induced draft cooling towers, illustrated in Figure 11, are constructed such that the incoming circulating water is dispersed throughout the cooling tower via a spray header. The spray is directed down over baffles that are designed to maximize the contact between water and air. The air is drawn through the baffled area [...]
Cooling Towers 2008-03-08 21:24:25 Purpose
Before the development of cooling towers, rivers, lakes, and cooling ponds were required to supply cooling. Through the development of the mechanical draft cooling tower, as little as one square foot of area is needed for every 1000 square feet required for a cooling pond or lake. Cooling
towers minimize the thermal pollution of the [...] Read more:Towers
Boilers 2008-03-08 21:22:02 Introduction
The primary function of a boiler is to produce steam at a given pressure and temperature. To accomplish this, the boiler serves as a furnace where air is mixed with fuel in a controlled combustion process to release large quantities of heat. The pressure-tight construction of a boiler provides a means to absorb the heat [...]
Hydraulics 2008-03-08 21:17:26 Hydraulic Operation
The operation of a typical hydraulic system is illustrated in Figure 8. Oil from a tank or reservoir flows through a pipe into a pump. Often a filter is provided on the pump suction to remove impurities from the oil. The pump, usually a gear-type, positive displacement pump, can be driven by an electric [...]
Hazards of Compressed Air 2008-03-08 17:21:40 Hazards of Compressed
Air
People often lack respect for the power in compressed air because air is so common and is often viewed as harmless. At sufficient pressures, compressed air can cause serious damage if handled incorrectly. To minimize the hazards of working with compressed air, all safety precautions should be followed closely.
Small leaks or breaks [...] Read more:Hazards
Compressor Coolers 2008-03-08 17:19:43 Compressor Coolers
The amount of moisture that air can hold is inversely proportional to the pressure of the air. As the pressure of the air increases, the amount of moisture that air can hold decreases. The amount of moisture that air can hold is also proportional to the temperature of the air. As the temperature of [...] Read more:Compressor
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