Tubing support

This implies that the LMTD or M I D as computed in equations 20 through 26 may not be a representative temperature difference between the two heat-transferring fluids for aU tubes. The effective LMTD or M ID would be smaller than the value calculated, and consequentiy would require additional heat-transfer area. The tme value of the effective M I D may be determined by two- or three-dimensional thermal—hydrauUc analysis of the tube bundle. Baffle—Tube Support PlateXirea. The portion of a heat-transfer tube that passes through the flow baffle—tube support plates is usuaUy considered inactive from a heat-transfer standpoint. However, this inactive area must be included in the determination of the total length of the heat-transfer tube. 

OTSGs also experience deposition of material on the flow areas in the tube support plates which causes an increase in pressure drop and eventual reductions in plant power production. 

Baffles are provided for heat-transfer purposes. When shell-side baffles are not required for heat-transfer purposes, as may be the case in condensers or reboilers, tube supports are installed. 

FIG. 11-44 Typical construction of a tube bundle with plug headers (1) tube sheet (2) plug sheet (3) top and bottom plates (4) end plate (5) tube (6) pass partition (7) stiffener (8) plug (9) nozzle (10) side frame (11) tube spacer (12) tube-support cross member (13) tube keeper (14) vent (15) drain (16) instrument connection. (API Standard 661.)... 

Internal Cake Tube Filters or Liquid Bag Filters This type of filter, such as manufactured by Industrial Filter and Pump Mfg. Co., Rosedale, Illinois, and many others, utihzes one or more perforated tubes supported by a tube sheet or by the hp of the pressure vessel. A cyhndrical filter bag sealed at one end is inserted into the perforated... 

External-Cake Tubular Filters Several filter designs are available with vertical tubes supported by a filtrate-chamber tube sheet in a vertical cylindrical vessel (Fig. 18-115). The tubes may be made of wire cloth porous ceramic, carbon, plastic, or metal or closely wound wire. The tubes may have a filter cloth on the outside. Frequently a filter-aid precoat will be applied to the tubes. The prefilt slurry is fed near the bottom of the vertical vessel. The filtrate passes from the outside to the inside of the tubes and into a filtrate chamber at the top or the bottom of the vessel. The sohds form a cake on the outside ofthe tubes with the filter area actually increasing as the cake builds up, partially compensating for the increased flow resistance of the thicker cake. The filtration cycle continues until the differential pressure reaches a specified level, or until about 25 mm (1 in) of cake thickness is obtainea... 

Environment Tube side Sea water, 0.25 ppm total residual chlorine, continuous, 40-90°F (4-32°C), pH 7.5-8.5, pressure estimated 15-50 psig (103-345 kPa), tubes supported by support plates... 

Fig. 16-8 Impressed current anodes for protecting tube supports of a loading bridge.

Interior wolkwoy Access walkway Tube Support cog Plenum boff le Dusi inlet port Fell tubes... 

Above temperatures of 900°F, the austenitic stainless steel and other high alloy materials demonstrate inereas-ingly superior creep and stress-rupture properties over the chromium-molybdenum steels. For furnace hangers, tube supports, and other hardware exposed to firebox temperatures, cast alloys of 25 Cr-20 Ni and 25 Cr-12 Ni are frequently used. These materials are also generally needed because of their resistanee to oxidation and other high temperature corrodents. 

The tube bundle is fabricated as a rigid structure to be handled as an individual assembly. Structural steel side members and tube supports are used for this purpose. Such supports are used beneath the bottom of the tubes to prevent the... 

Schiene,/. rail skid slat, strip, bar beam tube support rim, tire (of a wheel) (Med.) splint. 

Tubulus, m, tubulure, tubulation tubule. Tubus, m. tube tubulure. -aufsatz, m. tube attachment, -auszug, m. drawtube. -rbhre, /. (Micros.) drawtube. -schlitten, m. tube slide, -trager, m, tube support. 

Cells used for high-temperature measurements in furnaces often consist of silica sample tubes, supported by thin vanadium sleeves. The key to the analysis is whether it is possible to have a container that scatters in a sufficiently predictable way, so that its background contribution can be subtracted. With the current neutron flux available from both pulsed and reactor sources, sample volumes of... 

Verticol Tube Supports Tube Sheet Cut5l-t% ... 

Figure 10-81. Illustration for Example 10-11. (A) Temperature profile for fluid desuperheating and condensing. (B) Baffle and tube support layout.

The pressure drop due to condensing is usually negligible in a unit of this type. As a maximum, it may be taken as one half of the gas flow drop calculated for one baffle. This would be 1.16/8 = 0.145 psi for the condensing portion. Note that this does not recognize tube supports at 50% cut area, but for pressure units, this pressure drop will be nil. 

For longer units requiring support plates for the tubes, the pressure drop will still be very small or negligible and can be estimated by Figure 10-140 using the appropriate baffle cut curve to match the tube support cut-out of about 50%. Kem recommends that the flow be considered similar to an annulus of a double pipe and treated accordingly. 

B is held to a 2-in. minimum or V5 shell diameter (I.D.) and is 26 in. maximum for -in. tubes and 30 in. for 1-in. tubes. Refer to TEMA for tube support and baffle spacing recommendations. 

NOTE Denting is a phenomenon affecting tubes and tube supports. It is caused by the buildup of voluminous metallic oxides (such as copper oxide from FW heaters and iron oxide from carbon steel components), plus chloride ions. The deposit buildup distorts equipment and causes dents. 

FIGURE 9.4 The direct force measurement apparatus shown here ean measure the forees between two eurved molecularly smooth surfaces in liquids. Mica surfaces, either raw or eoated, are the primary surfaees used in this apparatus. The separation between the surfaces is measured by optieal teehniques to better than 10 nm. The distance between the two surfaces is controlled by a three-stage meehanism that ineludes a voltage-driven piezoelectric crystal tube supporting the upper mica surface this crystal tube can be displaced less than 10 nm in a controlled fashion. A force-measuring spring is attached to the lower mica surface and its stiffness can be varied by a factor of 1,000 by shifting the position of a movable clamp. Reprinted with permission from Proc. Natl. Acad Sci. USA, 84, July 1987, 4722. 

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