US2337907A

US2337907A - Adjustable sector plate

Info

Publication number: US2337907A
Application number: US446351A
Authority: US
Inventors: Ernest A Lundstrom
Original assignee: Air Preheater Co Inc
Current assignee: Alstom Power Inc
Priority date: 1942-06-09
Filing date: 1942-06-09
Publication date: 1943-12-28
Anticipated expiration: 1960-12-28

Description

Dec. 28, 1943. E, A. LUNDsTRoM' ADJUSTABLE SECTOR PLATE 2 Sheets-Sheet 1 Filed June 9, 1942 6.7.5 /A/Er @9s Pass/6165 INVENTOR.

fw Ul l B graffi/7. [unda/mm De@ 28 1943 E. A. LUNDsTRoM ADJUSTABLE SECTOR PLATE 2 Sheets-Sheet 2 Filed June 9, 1942 VE- i E HTTORNE'Y SHUTTE THF RO TOR Patented Dec. 28, 1943 ADJUSTABLE sncroa PLATE smeet a. Lunestmm, weusviue, N. Y., assigner to The Air Preheater Corporation, New York,

Application .lune 9, 1942, Serial No. 446,351

(o1. ssi-6r Claims.

This invention relates to heat exchange apparatus and particularly to improvements in rotary, regenerative air preheaters employed in conjunction with furnaces fired with pulverized coal.

The proper combustion of pulverized coal mined in certain localities is difficult because of its high moisture content. Therefore, it is desirable to utilize primary air of very highl temperatures so as to provide sufficient heat for thoroughly drying the coal. The complete combustion of the fuel also requires secondary air, and a rotary air preheater constructed to provide a supply of very hot primary air and also heated, but relatively cooler, secondary air is disclosed in the copending application of Roland S. Cooper filed November 9, 1940, under Serial No. 354,969. This preheater has a sector plate at the air outlet end formed with a special opening for primary air as Well as the usual opening for secondary air, both being alined with the air passage through the preheater with the primary air opening so located that immediately after the heat transfer elements leave the gas passage of end of the housing, i. e. each sector plate has anl opening for gas and a single opening for air, these openings being separated by a diametrically extending imperforate portion of the sector plate. In accordance with the invention the air outlet opening of the preheater is provided with wedge shaped shutter movable to divide it into two parts, one for primary and one for secondary air. By movement of the shutter away from or toward the edge of the air opening nearest the gas passage of the preheater, the size of the outlet opening for primary air may be enlarged or diminished. Depending upon the adjustment of the movable shutter, air passing to the primary air duct traverses a greater or lesser cross-sec- 'thus eliminates varyingv the load of the vair fan or fans.

Inv the accompanying drawings:

Figure 1 is a sectional elevation of a rotary regenerative air preheater embodying the present invention;

Figure 2 is a sectional View on the line 2-2 in Figure 1 affording a plan View of the sector plate at the air outlet end `of the preheater together with the adjustable wedge-shaped shutter provided for regulating'the size of the primary air outlet opening;

Figure 3 shows on an enlarged scale that part of Figure 2* illustrating the adjustable shutter and the operating mechanism therefor;

Figures l and 5 are sectional views taken along the correspondingly numbered section lines in Figure 2 or 3 and illustrate the mounting devices and operating mechanism for the adjustable shutter; and

Figure 6 is an enlarged sectional view on line tof Figure 4 of a sealing device associated with. the adjustable shutter.

The` air preheater shown in Figure l is of the familiar rotary regenerative type according to Ljungstrom Patent No; 1,522,825, issued January 13, 1925; it has a stationary housing il within which is mounted a cylindrical rotor li divided by radial partitions or diaphragms l2 into a plurality of sector-shaped compartments each containing regenerative heat transfer surface in the form of undulated or corrugated metallic plate i3. These plates rst absorb heat from hot gases when moving through the gas side of the preheater and then impart the heat to air in travelling through the air side of the preheater as the rotor is turned slowly about its axis lli in a clock- Wise direction (Fig. 2) by a motor (not shown) operating through suitable reduction gearing. The outlet duct for gas is designated iii in Fig. 1 and the inlet and outlet ducts for air are numbered il, i8 respectively.

At each end of the housing opposite the rotor il is a sector plate (Fig. 2) designated as a whole by the numeral 23. It consists of an annulus 2l with a diametrical web providing two large openings Ril and 25 separated by the imperforate radial web portions 26 and deiining the gas and air passages of the preheater. The radial partitions i 2 are provided with radial seals 23 adapted as the rotor turns to bear against the imperforate portions 2li of the sector plates Eil to prevent the flow of fluids across the ends oi the rotor between the gas and air passages of the preheater, the web portions ,26 being of greater width than the 21 arcs subtended by the various sector-shaped compartments into'which the rotor is divided by the partitions. The Iconstruction described above is conventional.

The preheater shown herein has a special outlet conduit 30 for primary air in addition to the y outlet conduit 3l for secondary air, both merging with the usual air outlet duct I 8 as appears in Fig. 1. According to the presentinvention 'there is mounted inthe air outlet opening 25 in vthe lower sector plate 2D an adjustable shutter 32. The shutter is shaped at its inner edge to conform to the part 2l of the imperforate web 26 that rings the rotor post I4 and at its outer vend to the curvature of the inner radiusv ofthe annular section 2| of the sector plate that denes one side of the air outlet 25. As appears in Figure 5, arc shaped ledges 33 are .provided adjacent the outer and inner edges ofthe air opening 25 at the end thereof where the plates I3 first emerge 'from' .the gas passage; The ledges 33 serve as guide tracks on which the end edges of depending flange portions 34 of shutter 32 ride.` The flanges 34 carry toothed racks 49, 4I engaging with gears 42, I3 carried by a radially disposed shaft 44 suitably journalled within'thel duct I8 just beyond one end of the ledges 33 that support shutter 32. Meshing with the gear t3 is a pinion-difixed to a vstub shaft extending through the outer/wall of the duct I8 and provided with a lever 46 operable to drive the gears 612, 43 and move the shutter'32 away from or toward. the edge 36 of airpassage 25 for increasing orA decreasing the sizeof the opening 3l opposite the primary .air conduit 4S. A latch l (Fig. 4) engageable with anotched sector 48 is provided to hold shutter 32 in its adjusted position.

Extending upwardly from the juncture S (Fig. 1) of the primary air conduit 30 and secondary air conduit 3l is a partition 5i subdividing the finterior'v of :air outlet duct I8 immediately below the lower sector plate 20 to direct the air from the primary air opening 3l into the primary air conduit 3E and the air from the remaining section 38 of airr passage 25 into the secondary air conduit 3i. The lower part 52 of partition 5I is sloped to meet the inner side of conduit S0. `The upper .portion 53 of partition 5I extends radially and is provided with a radial seal 54 in contact with the undersid-e of the movable shutter 32 so as to prevent cross iiow of primary and secondary air.

In operation dampers 56 in the primary and secondary air ducts are adjusted to apportion Vthe total volume of airflowing through the preheater between the furnace connected to the secondary air duct .3l and the fuel vdrying mill or other apparatus :to which duct 30 leads. The further Iaway the shutter 32 is positioned from the edge 36 of opening 25 the greater will be the vsize of the primary air opening 31 and the amount of heat transfer surface in the direct path of primary air. Thus as the size of open- .ing 31 is increased, the temperature of the volume of primary air as determined by the adjustment of dampers 55, 55 is raised. When the shutter 32 is moved counterclockwise reducing the size of opening 3'! the resistance created by obscuring the lower end of passages between plates I3 above the shutter causes substantially the entire volume of primary air tov follow the path of least resistance and traverse passages between .plates I3 registering with opening 3l. As a re- :sult of traversing a small amount of heat trans- ;fer surface the primary air is less intensely heated. The dampers 55 and 56 are provided so that upon movement of shutter 32 to regulate the temperature of the primary air the same relative volume of primary air may be obtained by adjusting them to compensate for decreased or increased resistance through the primary air section of the rotor as the shutter is opened to increase or to decrease the primary air temperature.

What is claimed is:

1. In regenerative heat exchange apparatus having passages for a heating gas and air or other gaseous fluid to be heated, ducts for supplying hot gas and relatively cool air thereto, and a rotor carrying regenerative material adapted to be moved first through the gas passage for absorbing heat from the gases flowing therethrough and then into the air passage to impart heat to the air -iiowing therethrough; a

'sector plate at the air outlet end of the preheater lhaving an opening opposite the end of the rotor for .the discharge of heated air; an offtake conduit communicating with a determined portion of said air outlet opening that is located adjacent the point yof entrance of the heated regenerative material into the air passage during rotor movement; means for regulating the volume of air vilowingthrough the rotor into said conduit; a movable, imperforate shutter disposed intermediate'the air outlet'end of said rotor and said outlet conduit to partially obscure the portion. of said end of said rotor that communicates with said conduit so as to concentrate the flow of air through the unobscured section of the rotor registering with said portion of the opening in said sector plate; and means Yfor adjustably Apositioning said shutter.

2. In regenerative heat exchange apparatus having passages for a heating gas and air or other gaseous uid to be heated, ducts for supplying hot gas and relatively cool air thereto, and a rotor carrying regenerative material adapted to be moved rst through the gas passage for absorbing heat from the gases flowing therethrough and then into the air passage to impart heat to the air flowing therethrough; a sector plate at the air outlet end of the preheater having an opening for the discharge of heated air; an air oiftalre conduit communicating With a detervsaid rotor and communicating with said primary air conduit; and means for adjustably position- `ing said shutter.

3. In vregenerative heat exchange apparatus .having passagesffor a heating gas and air or other gaseous fluid to be heated, ducts for supplying hot gas and relatively cool air thereto, and a rotor carrying regenerative material adapted to be moved rst through the gas passage for absorbing heat from the gases flowing therethrough and then into the air passage to impart heat to the air flowing therethrough; a sector plate at the air outlet end of the preheater having an opening opposite the end vof the rotor for the `discharge of heated air; a `primary air conduit communicating with a determined portion of said lair outlet opening that is located adjacent the point of entrance of the heated regenerative material into the air passage during rotor movement; a secondary air conduit located beyond said primary air conduit in the direction of rotor movement and communicating with the remainder of said air outlet opening; damper means in said conduits for apportioning between them the volume of air flowingthrough the air passage; a movable, imperforate shutter disposed opposite the end of said rotor intermediate it and said primary airconduit and partially obscuring the portion of the opening in said sector plate that communicates with said primary air conduit so as to reduce the area of the part of said opening aiording free ow of air between the rotor and said conduit; and means for moving said shutter to'vary the area of said portion of the air outlet opening that affords lfree flow between said rotor and conduit.

4. In regenerative heat exchange apparatus having passages for a heating gas and air or other gaseous nuid to be heated, ducts for supplying hot gas and relatively cool air thereto, and a rotor carrying regenerative material adapted to be moved first through the gas passage for *absorbing heat from the gases flowing therethrough and then into the air passage to impart heat to the air flowing therethrough; a sector plate,l at the air outlet end of the preheater havl ing an opening opposite the end of the rotor for l* thejdischarge of heated air; a partition associthe outlet opening; a movable, imperforate shutter disposed between the end of said rotor and said partition for partially obscuring said portion of said outlet opening to concentrate the flow of l air through the section of the rotor registering with the unobscured part thereof; sealing means carried by said partition and bearing against said shutter; and means for adiustably positioning said shutter.

5. In regenerative heat exchange apparatus having passages for a heating gas and air or other gaseous fluid to be heated, ducts for supplying hot gas and relatively cool air thereto, and

Va rotor carrying regenerative material adapted to be moved first throughthe gas passage for absorbing heat from the gases flowing therethrough and then into the air passage to impart heat to the air flowing therethrough; a sector plate at the air outlet end of the preheater having an opening opposite the end of said rotor for the discharge of heated air; partition means associated with said sector plate acting to set oi a portion of predetermined area, adjacent the point of entrance of said rotor into the air passage, from the remainder of said air outlet opening; an offtake conduit communicating with said portion of said outlet opening; a movable, imperforate shutter disposed between the end of said rotor and said partition or partially obscuring said portion of said outlet opening to concentrate the ow of air through the section of the rotor registering with the obscured part thereof; means for adjustably positioning said shutter; and sealing means carried by said partition and bearing against said shutter to prevent leakage of air to or from said portion of said air outlet opening in various positions of said shutter.

ERNEST A. LUNDSTROM.