Header pipe

After exiting the economizer, the feedwater is directed iato the boilet s cylindrical steam dmm via a common header pipe that penetrates the dmm s wall and distributes the water evenly within the dmm through holes drilled ia the upper side of the distribution pipe. Because the distribution pipe is located axially below the waterline ia the lower section of the steam dmm, the incoming feedwater mixes thoroughly with the water ia the dmm and prevents any significantly uneven temperature distributions within the dmm. 

The superheated steam generated in the superheater section is coHected in a header pipe that leads to the plant s high pressure steam turbine. The steam turbine s rotor consists of consecutive sets of large, curved, steel aHoy disks, each of which anchors a row of precision-cast turbine blades, also caHed buckets, which protmde tangentiaHy from the shaft and impart rotation to the shaft when impacted by jets of high pressure steam. Rows of stationary blades are anchored to the steam turbine s outer sheH and are located between the rows of moving rotor blades. 

FIG. 25-73 Typical detail of a passive gas venting system with a header pipe. (From Bagchi, A, Design, Construction, and Monitoring of Sanitary Landfill, Wiley, 1990.)... 

O Stainless sti oil supply header piping Q Fittralion, Microns... 

Manifold A section in the exhaust air ductwork of an air treatment system into which exhaust air enters from a number of orifices or ducts, or a header pipe in a fluid flow system that has branches. 

A well point system consists of several individual well points spaced at 0.6 m to 1.8 m intervals along a specified alignment. A well point is a well screen (length 0.5 to 1.0 m) with a conical steel drive point at bottom. Individual well points are attached to a riser pipe (diameter 2.5 to 7.5 cm) and connected to a header pipe (diameter 15 to 20 cm). At the midpoint, the header pipe is connected to a centrifugal pump. As yield at different well points may vary, a valve at the top of each riser pipe is used to control the drawdown so that the screen bottom is exposed. The pump provides 6 to 7.5 m of suction, but friction losses reduce the effective suction to 4.5 to 5.4 m. 

Similarly, the main header pipe should be sized based on the following equation ... 

To determine the header-pipe size, first determine the maximum number of holes in ring section supplied by a single effective entry of gas. If outer most ring is supplied by four gas entry points, then the number of effective gas entry points is 8, and the number of holes in each section of ring No. 4 would be Nh = 978/8 = 122. Then Eq. (13) gives ... 

Th = header pipe thickness (measured or minimum per purchase specification)... 

The reinforcement area and reinforcement zone shall be calculated in accordance with para. IP-3.4.2 or IP-3.4.3, considering the subscript h and other references to the run or header pipe as applying to the closure. Where the closure is curved, the boundaries of the reinforcement zone shall follow the contour of the closure, and dimensions of the reinforcement zone shall be measured parallel to and perpendicular to the closure surface. 

Caution If the inlet side T1 for any cylinder end is hotter than the main gas inlet header pipe, then there is zero gas flow through this cylinder end. Then both the adiabatic and relative compression efficiencies are also zero. 

Header pipe. This is usually made of redwood staves for very large towers. 

Cooling tower, cooling tower pumps, header piping. 

The backwash system used by Zum, for instance, employs two header pipes one operates continuously at 20 psi, while the other operates at 40-55 psi. Under normal operating conditions, these jets operate at 35 psi. Once a day they are operated at 50 psi for 30 min to keep the jets free of slime buildup. Should this procedure fail to keep the jets clean, the pressure is raised to 55 psi. At this pressure the spring-loaded jet mouth widens to allow for more effective cleaning. 

The basic heat-transfer surface is a bank of 1 to 20 (but usually 3 to 12) rows of high-tinned tubes. The fluids enter the tubes by box headers (pipe headers at higher pressures), with the tubes welded into one wall of the header internal dividers are used in the headers to create multiple tube passes. The header cover may be bolted to the header, or the header may be welded, with threaded plugs opposite the tube ends to facilitate assembly and tube cleaning. The tubes are slanted downward toward the exit (about 1/4 in. per ft) to facilitate drainage. Occasionally, especially for turbine steam condensation, an A-frame configuration is employed, with the tubes slanted about 30° from the vertical and the fans mounted in forced draft at the base of the A, thereby reducing the plan area required. 

Sulfur-coating drum build-ups. Such build-ups appear to have been eliminated. A related problem of agglomerates caused by sulfur particles coalescing on the hot header piping with subsequent dripping of molten sulfur into the bed of urea has also been substantially reduced. 

Nominal branch-pipe wall thickness Nominal header-pipe wall thickness Head or shell radius Pressure design thickness Time... 

Trickle (Solar) Collector - A type of solar thermal collector in which a heat transfer fluid drips out of header pipe at the top of the collector, runs down the collector absorber and into a tray at the bottom where it drains to a storage tank. 

---