US2038417A - Integral fan and fan housing - Google Patents

Description

5 Sheets-Sheet 1 H. S. COLBY INTEGRAL FAN AND FAN HOUSING Original Filed March '7, 1929 April 21, 1936.

I NVENTOR April21-,1 936 H.S.COLBY I I ,038,

INTEGRAL FAN AND FAN HOUSING Original Filed March '7, 1929 5 Sheets-Sheet 2 I NVENTOR H. S. COLBY INTEGRAL FAN AND FAN HOUSING 5 Sheets-Sheet 3 Original Filed March 7, 1929 INVENTOR' J I 25 44 4,; ATTORNEY April 21, 1936. s, COLBY 2,038,417

INTEGRAL FAN AND FAN HOUSING Original Filed March 7, 1929 5 Sheets-Sheet 4 INVENTO April 21, 1936. COLBY 2,038,417

INTEGRAL FAN AND FAN HOUSING Origifial Filed March 7, 1929 5 Sheets-Sheet 5 ATTO NEY Patented Apr. 21, 1936 UNITED STATES PATENT ()FFl INTEGRAL FAN AND FAN HOUSING Haldwell s. Colby, Port Washington, N. Y.

Application March 7, 1929, Serial No. 345,011 Renewed June "8, 1934 9 Claims. (01. 236429) The present invention relates to integral fans and housings therefor, and particularly to fans trifugal forced draft fan housings, induced draft fan housings, ducts for connecting the housings to the air preheater and foundations for supporting the fans and their drive motors. When us ing axial flow fans, the initial installation cost is very much less than that of centrifugal fans, and this difference in cost more than offsets the slight increase in efficiency obtained with centrifugal fans. Among the advantages resulting from a fan installation in accordance with the present invention are the use of a common shaft for the forced draft and the induced draft fans, the formation of the fan housing as an integral unit and the provision of relative adjustment of the fan capacities, thus compensating for slight differences in the requirements of individual installations.

Other advantages and objects are disclosed in, and will be readily apparent from, the detailed description following and the accompanying drawings, wherein:

Fig. 1 is a sectional elevation of the fan housing mounted on the air preheater, and the forced and induced draft fans mounted therein;

Fig. 2 is a plan view of the housing, showing the exhaust outlet duct and the guide blades for the inlet air;

Fig. 3 is a view, partly in section, showing a fan blade mounting, and the adjustment permitting turning of the blade;

Fig. 4 is a section on the line 4-4 of Fig. 3, showing the seating of the bolt heads in the fan brackets;

Fig. 5 is an elevation, partly in section, of a modified fan installation;

Fig. 6 is a plan view of the modification shown in Fig. 5; and

Fig. 7 is a detail View, in section, through-the carrying roller of the rotor.

Considering the drawings, the fan housing 5 is positioned above the air preheater casing 6', as shown in Fig. l, and includes a base section 1 separated by a partition 8 into an air inlet duct 9 and a flue gas outlet duct Ill. The fan housing is divided into an inlet air compartment H and a flue gas compartment l2, respectively communicating through ports l3, I4 with the two ducts 9, Ill.

The inlet air compartment II has a lateral inlet port I5; a spider I6 is positioned in the inlet l5 and has guide vanes or blades l1 for guiding the incoming air to the forced draft fans.

The flue gas compartment has an outlet port l8 through which the cooled flue gases pass to the stack. Extending through both compartments is a common shaft IS on which are mounted forced draft fans 20, 2|, positioned within the inlet air compartment and induced draft fans 22, 23 positioned in the flue gas compartment.

Curved surfaces 24, 25 secured to a central partition 26 respectively guide the compressed air and the'outgoing flue gases to ports I3, IS, a central partition 21 cooperating with a labyrinth packing 28 on the shaft l9 and completing the separation of the air-and flue gas passageways. The curved surfaces 24, 25 and the sides of the compartment form oppositely positioned spiral scrolls, the air scroll extending downwardly and the flue gas scroll extending upwardly, thus balancing the housing.

The common shaft I 9 is mounted at one end in a bearing 29 which is preferably supported by a bracket 30 secured to the base section 1. The other end of the shaft is preferably mounted in a bearing 3| supported within the spider 16. Power may be applied to the shaft in any desired manner, one preferred form comprising a motor 32 mounted on a supporting bracket depending from the fan housing. The compartment l2 has a side opening 33 through which the shaft extends, a removable diaphragm 34, sealed adjacent the shaft, permitting ready access to the compartment interior and the fans therein.

Each fan blade 35, as will be noted from Figs. 3 and 4, is adjustably mounted with respect to the fan disk 36, and is positioned between fan brackets 31, 38, rivets or the like securely holding the fan blade in position. Each fan bracket has elongated slots 40 through which bolts 4| pass to secure the brackets to the fan disk, the elongated slots permitting turning of the brackets and fan blade around the central bolt of bracket 31. The preferred embodiment includes five bolts to rigidly hold the fan blade in adjusted "position; The fan disk 36 may be planed to present a flat surface for receiving the brackets, but the preferred method of adjustment is to apply the brackets while hot, and then tighten the bolts in place, the bolt heads 42 engaging recesses 43 within each bracket.

In the modified form of installation shown in Figs. 5 and 6, the fan scrolls, indicated at 44, 45, are not enclosed by a cylindrical shell, as in Fig. l, but instead are mounted on top of the rotor support housing I, which thus forms a base or foundation for the fan unit. The motor bracket I rying'the preheater. The modified form permits repairs to the fan structure to be conveniently made.

Fig. '7 shows, in section, one of the supporting rollers 46 for the preheater rotor 41.

While the preferred method of adjusting the fan capacities comprises adjusting. the fan blades, an adjustment of the relative fan capacities may also be made by positioning louvre dampers (not shown) in the fan outlets for controlling the relative volumes required for both fans.

An adjustment may also be made by using separate aligned shafts for the two fans, preferably positioned in independent fan scrolls, and driving each shaft independently, whereby the relative capacities of the fans may be changed by varying the speeds of the separate motors. In such installation, a quick disengaging coupling is positioned between the two fan scrolls, so as to be accessible from the outside, to connect the adjacent ends of the aligned shafts, and permit driving of both fans from one motor in the event of failure of either of the drive motors.

The use of a common housing and a common shaft for both sets of fans facilitates construction, lowers the cost of installation and upkeep, and permits use of outside shaft bearings which are not exposed to the hot gases; the adjustment of the relative fan capacities results in attainment of maximum fan efficiency for each individual installation.

Having thus described the invention, I claim:

1. In a fan arrangement for an air preheater, tWiU adjacent fan scrolls separated by a partition, a fan shaft extending through said scrolls and partition, bearings for said shaft exterior to said scrolls, said scrolls including curved guide surfaces divergently extending from said partition toward said shaft, and axial flow impeller fans mounted on said shaft adjacent the shaft ends of said guide surfaces, said fans each including a disk part and a blade part secured bybolts to said disk part, one of the bolts being centrally positioned with respect to the other bolts, one of said parts having a circular opening for the centrally positioned bolt and circumferentially spaced slots for the remaining bolts, the other part having circular holes for all the bolts.

2. In a fan arrangement for an air preheater, two adjacent fan scrolls separated by a partition, a fan shaft extending through said scrolls and partition, bearings for said shaft exterior to said scrolls, said scrolls including curved guide surfaces divergently extending from said partition toward said shaft, and axial fiow impeller fans mounted on said shaft adjacent the shaft ends of said guide surfaces, said fans each including a disk part and a blade part secured by bolts to said disk part, one of the bolts being centrally positioned with respect to the other bolts, the blade part having a circular opening for the centrally positioned bolt end and circumferentially spaced slots for the remaining bolts, and the disk part having circular openings for all the bolts.

3. In a fan arrangement for an air preheater, a housing, a double scroll construction therein comprising two contiguous fan scrolls having their inner adjacent ends secured to said housing and their free outer ends extending outwardly towards the scroll axes, a fan shaft axially positioned in said scroll construction, axial flow fans mounted on said shaft adjacent the ends of said scroll construction, and bearings for said shaft mounted on said housing, and exterior to said scroll construction.

4. In a fan arrangement for an air preheater, a housing, a double scroll construction therein comprising two contiguous fan scrolls having their inner adjacent ends secured to said housing and their free outer ends extending outwardly towards the scroll axis, a fan shaft axially positioned in said scroll construction, axial flow fans mounted on said shaft adjacent the ends of said scroll construction, sealing means between said scroll construction and said shaft and bearings for said shaft mounted on said housing and ex- .terior to said scroll construction.

5. In a fan arrangement for an air preheater, a housing, a double scroll construction therein comprising two contiguous fan scrolls having their inner adjacent ends secured to said housing and their free outer ends extending outwardly towards the scroll axes, said scrolls each having axial inlets and radial outlets, a fan shaft axially positioned in said scroll construction, axial flow fans mounted on said shaft adjacent the ends of said scroll construction, and bearings for said shaft mounted on said housing, and exterior to said scroll construction.

6. In a fan arrangement for an air preheater, a housing, a double scroll construction therein comprising two contiguous fan scrolls having their inner adjacent ends secure-d to said housing and their free outer ends extending outwardly towards the scroll axis, said scrolls each having axial inlets and radial outlets, a fan shaft axially positioned in said scroll construction, axial flow fans mounted on said shaft adjacent the ends of said scroll construction, sealing means between said scroll construction and said shaft, and bearings for said shaft mounted on said housing, and exterior to said scroll construction.

7. In a fan'arrangement for an air preheater, a housing, a double scroll construction therein comprising two contiguous fan scrolls having their inner adjacent ends secure-d to said housing and their free outer ends extending outwardly towards the scroll axes, a fan shaft axially positioned in said'scroll construction, axial flow fans mounted on said shaft adjacent the ends of said scroll construction, means for varying the relative capacities ,of said fans, and bearings for said fans mounted on said shaft adjacent the ends:

of said scroll construction, sealing means between said scroll construction and said shaft, means for varying the relative capacities of said fans, and

bearings for said shaft mounted on said housing, and exterior to said scroll construction.

9. In afan arrangement for an air preheater, a housing, spaced bearings mounted ,on said housing, and positioned adjacent the ends of said housing, a fan shaft rotatably mounted in said spaced bearings, an axial flow fan mounted on 1 said shaft adjacent each end of said housing, two contiguous fan scrolls having their inner ends secured to the housing and their free outer ends extending outwardly and terminating adjacent said fans, said fan scrolls being spaced from saidv fan shaft, and sealing means comprising cooperating elements respectively secured to said fan shaft and to one fan scroll.

HALDWELL S. COLBY.

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