US1447554A

US1447554A - Fan

Info

Publication number: US1447554A
Application number: US287273A
Authority: US
Inventors: Jones William Anthony
Original assignee: Individual
Current assignee: Individual
Priority date: 1919-04-03
Filing date: 1919-04-03
Publication date: 1923-03-06
Anticipated expiration: 1940-03-06

Description

Mar. 6, 1923'.

w. A. JONES 'FAN Filed Apr. 5, 1919 3 sheets-sheet l INVENTOR.

W. A. JONES FAN 5 sheets-sheet 2 Filed Apr.

INVENTOR.

WITNESSES Mar. 6, 1923.,

1,447,554 W. A. JONES FAN Filed Apr. 5, 1 1

3 sheets-sheeo 5 Patented Mar. 6, 1923.

warren stares WILLIAM ANTHONY'JON'E S, OF WEST NEW BRIGHTON, NEW YORK? FAN.

Application filed April 3, 1919. Serial No. 287,273.

To all whom it mar/y concern Be it known that I, l/VILLIAM ANTHONY JoNEs, a citizen of the United States, and resident of West New Brighton, county of Richmond, and State of New York, have invented-certain new and useful Improvements in Fans, of which the following is a which results from a chimney in order to cause gases to flow through passages provided forthcm and through various heat absorbing apparatus.

It frequently happens that the products of combustion are charged with a quantity of fine dust which it is desired to separate from the gases.

In the case of cement kilns the dust which is carried away by the waste gases is very valuable.

In the case of burning finesizes of hard coal the dust which is carried out of the stack is objectionable in the neighborhood.

Ordinary centrifugal fans receive gas at the center, parallel to the axis, and discharge it radially, which necessitates a right-angle change of direction of the gases and makes it difficult to obtain a gradual decrease and increase of gas passage cross-sectional area with a corresponding gradual increase and decrease of gas velocity which conduces to efliciency. I

Ordinary disc fans operate on gas at widely different distances'from the center, and it is impossible to have equally good efficiency at all points. Ordinary disc fans act on the gas without imparting any considerable rotary motion to the gas and the axial motion which they impart to the gas is accompanied by a heavy axial thrust on-the fan.

In the accompanying drawings, Figure 1 is a longitudinal section through the fan and easing. Figure 2 is an end View, partly in section on the line AA'of Figure l, of the discharge end of the casing. Figure 3 shows a part view of the fan wheel. Figure 4 is a development of a cylindrical surface concentrio with the axis and shows the intersection of this surface with the blades of the fan and with the stationary guide vanes at each side of the fan. Fig. 5, is a plan view of my fan connected to a settling chamber. Fig. 6, is a vertical view, partly in section, of the structure shown in Fig. 5. Fig. 7 is a part section through the fan casing and bearings and shows pipes for conveying a cooling medium for the bearings. Fig. 8 is a development of a cylindrical surface concentric with the axis and shows the intersection of this surface with the blades of the fan and with stationary guide vanes at each side of the fan, Fig. 8 is like Fig. 4 except that an arrow, 88, is shown to represent the path of a particle of dust, and arrows, NP, are shown to represent pressures normal to the guide vanes and normal to the blades of the fan. Fig. 9 is a part section on the line, GG, through the outlet, Q, for dust and-shows a View in plan of the arrow, 88.

Similar parts are referred to by similar letters throughout the several views.

Referring to the drawings: a fan wheel a, provided with blades 1), is mounted on a shaft 0. A gear d is fastened to the fan wheel and is driven by pinion wheel 6 mounted on shaft f which extends outside of the fan casing.

The fan casing is represented as made of an inletpart g and an outlet part it. A conical shield 2', concentric with the inlet part g of the fan casing, shields the central part of the fan wheel a. A similar conical shield j shields the central part of the fan wheel at the other side in the outlet' part it.

The space k, between the conical shield Wand the inlet part g of the casing, forms a passage of gradually decreasing cross-sectional area for gas as it approaches the fan wheel blades 7). Stationary guide vanes l in the space 71;, between the conical shield i and the casing g, determine the direction, of flow of gas to the wheel. Similar stationary guide vanes m, in the space 4 between theconical shield j and the casing h, determine the direction of flow of the gas as it leaves the blades of the wheel. Inclination of the stationary guide vanes l and m, with respect to the axis, causes an axial thrust of the gases without a coresponding axial thrust on the fan wheel.

In additiog to the outlet passage a, a

second outlet passage 0, at a greater disoi the blades is also shown greater at the outlet side of the tan wheel for the same reason. I

The passage 0 for dust leads toorifice Q. from which dust may be conducted to a settling chamber. ln the settling chamber the velocity of the gas from the orifice Q may be reduced so that dust will be deposited. and this relatively small volume of gas may then be led to the inlet end of the fan again.

Figs. 5 and 6 show a settling chamber, cc, ol circulanform which is representative of one form of such a settling chamber. In this representation. dust laden gas enters the settling chamber tangentially. from the outlet. 0". maintaining a rotary motion of the gases within the chamber. Gases pass below the lower edge of a circular internal baille and then flow upward to the top of the chamber from which they may be conducted by ,the pipe. w. to the inlet side of the fan. The slow velocity of the gases in the large chamber and the change in the dil'iection of their flow causes the dust, with which the gases are laden, to be deposited in the dust settling chamber. The conical bottom of the chamber facilitates the dust being drawn oil through the valved opening, cw.

In its passage through the fan, the pressure ol the gas will be least at the fan wheel where the velocity of the gas will be greatest. that is to say. the pressure at r. between the blades of the fan wheel. will be less than the pressure. at a. at the inlet, or atf". at the outlet.

Ordinarily. therefore. it will be possible to cool the bearings 71/ or -the fan shaft c and pinion shatt f by allowing airto flow to these hearings through pipes from the atmosphere external to the casing, and such air may be discharged into the space within the conical shields '1'" and j from which it will flow through space r to mingle with the gases being acted upon by the fan.

()r. bearings may be cooled by water or by oil conducted to and from the bearings by suitable pipes pp and go, one arrangement of which is shown in Fig. 7.

A shield w, attached to the fan Wheel and projecting within a flange m of the conical shield i, is represented for retaining the oil used for lubricating gears d and e.

The blades 1) of the fan wheel a are represented in planes passing through the axis. This results in no end thrust on the fan wheel and in a relatively slow speed of fan wheel for a given velocity of gas.

By making the planes of the blades oblique to the axis with a retreating angle 3 with reference to the planes of the blades shown. the speed of the fan wheel may be increased with the same velocity of gas. lVhen oblique blades are used, there is an axial thrust on the tan. less than that of an ordinary disc fan, but the higher speed permits a high speed motor to be direct-connected to the fan without the necessity of reduction gears, even for low velocities of gas.

The action of the fan in causing gas to flow from a lower pressure to a higher pressure is as follows. Rotation of the fan wheel draws gas away from the spaces between the stationary vanes at the inlet side of the fan wheel and reduces the pressure at that point and this in turn causes gases to flow between the stationary vanes. at the inlet side. to the tan wheel. The gradual decrease in cross section of gas passage area at the inlet side permits the gases to acquire a relatively high velocity as they reach the wheel without the formation of eddies. In this respect the action of the gas passage of gradually decreasing cross section is like the action of a Venturi tube, the wheel of the fan being at the throat.

The efficiency of my invention is high because. like a Venturi tube. it is adapted to convert pressure into velocity, at the inlet side, and velocity into pressure. at the outlet side, and also be arise in passing through the apparatus gas has a very short path and for only a small part of that short path is it at high velocity. The first of these features reduces loss from eddies to a minimum and the second reduces loss from skin friction to a minimum.

The gradual increase in cross sectional area of the gas passages from the outlet side of the wheel is also like a Venturitube and.

effectively converts velocity into pressure.

The absence of axial thrust on the moving wheel also reduces loss and wear. The apparatus is particularly adapted for use as a vacuum cleaner. The thrust bearings of other vacuum cleaner tans wear out in a short time and the dust bags of such vacuum cleaners require frequent cleaning and offer resistance'to the passage of air.

The cross sectional area for gas flow at the wheel is even less than it appears at first glance being the difference in area of the circle of the body of the wheel and the area of the circle of the inside of the casing, multiplied by the sine of the angle of inclination of the stationary vanes. This disregards the thickness of the blades of the wheel.

As shown on the drawings the area of gas flow at the wheel, corresponding to the throat of a- Venturi tube, is abou'tone sixth of the area of gas flow at the inlet and at the outlet. If it is desired to handle gas against about seven inches of water pressure, corresponding to a velocity head of 475 feet for air at normal temperature, then they as velooity at the wheel would be about 1 5 feet per second and the velocity ofthe blades of the Wheel would be about 125 feet per second. Of course the proportions are varied to suit conditions.

In the conditions assumed above the velocity at the inlet would be about onesixth the velocity at the wheel, or about 29,feet per second, 1750 feet per minute.

The fact that, disregarding friction, the sum ofthe dynamic head and the pressure head is a constant in a Venturi tube is the basis of the Venturi' meter, where the decrease in pressure head at the throat, Where the velocity is highest, is used to calculate the velocity of flow.

In the ordinary Venturi tube the final pressure is slightly less than the initial-pressure due to friction.

In my. invention the blades of the {an wheel add to the velocity at the throatso that the final pressure is greater than the initial pressure.

The fact that the energy of motion is as the square of the velocity, makes it necessary to add only a small amount to the relatively high velocity, which the gas has when it reaches the wheel, in order to add suflicient kinetic energy to the gas to enable it to enter the higher pressure at the outlet of the fan. This relatively small increase in velocity is evidently accompanied with much less disturbance and loss in eddies and impact than when the blades of a fan wheel bite into stationary gas or gas flowing slowly in passage ways of relatively large cross sectional area, so that adjacent parts of the gas are suddenlytorn away at high velocity.

With the proportions shown on the drawings and described above, in my invention,

the blades of the fan wheel practically exert is moving tangentially to the conical shield and also in the direction of the stationary guide vane which is next to this particle of dust. By reason of its inertia, the particle of dust will tend to move forward in this direction in a straight line and in a given interval of time its distance from the axis of the fan will increase from R to R During this interval of time its transverse motion will be equal to the length of the line, L, and its longitudinal motion will be equal to the length of the line, L Evidently with the relative proportions shown, the direction of motion of this particle of dust will carry it into the outlet for dust, 0.

Evidently if the angle of the cone were less without increasing the width of the wheel or the Wheel were made narrower without increasing the angle of the cone, then the direction of motion of this particle of dust, which is tangent to the cone,

ing, '0, for dust. Again thisobject would not be attained if the diameter of the base of the cone were made smaller without making corresponding changes in the other dimensions of the fan.

The above shows that, with the proportions shown, the particle of dust next to the conical shield at the inlet side of the fan will be carried to the outlet for dust, 0. Evidently all other particlesof dust which are would not carry the particle into the openinitially at a greater distance from the axis of the fan, will have a less radial distance to go and will also be carried to the outlet for dust, o.

The particular arrangement shown may be altered without departing from principle of the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a shaft with bearings, a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, and a second concentric conical shield at the outlet side of the fan wheel, stationary vanes, oblique to the axis, between the conical shields and the shell of the casing, an inlet for. gas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, a second outlet for dust at a greater distance from the center than the first outlet, stationary vanes for determining thed'irection of flow of dust from the fan wheel blades to the second outlet, passages for conducting a cooling medium to the bearings.

v 2. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a shaft with bearings, a fan wheel with blades, a casing having a concentric conical shield at the inlet sideof the fan wheel, and a second concentric conical shield at the outlet side of the fan wheel, stationary vanes, oblique to the axis, between the conical shields and the shell of the easing, an inlet for gas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, a second outlet for dust at a greater distance from the center than the first outlet, stationary vanes for determining the direction of flow of dust from the fan wheel blades to the secondoutlet.

3. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination ofa" shaft with bearings, a fan wheel with blades, a casing having a concentric conical shield at the inlet side of the fan wheel, and a second concentric conical shield at the outlet side of the fan wheel, stationary vanes, oblique to the axis, between the conical shields and the shell of the easing, an inlet for gas at one side of the fanwheel, an outlet for gas at the other. side of the fan wheel, a second outlet for dust at a greater distance from the center than the first outlet.

4:. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a conical shield at the inlet side of the fan wheel, a second conical shield at the outlet sideof the fan wheel, stationary vanes between the conical shields and the shell of the casing, the cross sectional area for flow of gas being least at the fan wheel and gradually increasing at each side of the fan wheel, substantially as described.

5. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with blades, a casing having a conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the wheel, stationary vanes between the conical shields and the casing, with the vanes curved so that they are oblique to the axis near the fan wheel and are parallel to the axis at the point farthest from the fan wheel. the cross sectional area for flow of gas being least at the fan wheel and gradually increasing at each side.

6. In apparatus for causing gas to flow from a lower pressure to a higher pressure,

- the combination of a shaft with bearings, a

. cal shield at the outlet side of the fan wheel,

outlet side of the fan wheel, stationary vanes, oblique to the axis, between thr coni cal shields and the casing, all so that rotation of the fan wheel causes rotation of the gas at the fan wheel and the oblique stationary vanes cause an axial thrust on the gas, the cross sectional area. for flow of gas being least at the fan wheel where the velocity of gas is greatest, substantially as described.

-8. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a fan wheel with blades whose surfaces are formed of lines which are parallel to the axis of the fan wheel so that a pressure normal to the surfaces will not cause an axial thrust on the fan wheel, a casing, a conical shield at the inlet side of the fan wheel, a second conical shield at the outlet side of the tan wheel, stationary vanes, oblique to the axis, between the conical shields and the casing, all so that rotation of the fan wheel causes rotation of the gas at the fan wheel and the oblique stationary vanes cause an axial thrust on the gas, the cross sectional area for flow of gas being least at the fan wheel where the velocity of the gas is greatest, substantially as described. 9. In apparatus for causing gas to flow from a lower pressure to a higher pressure, the combination of a shaft with bearings, a fan wheel with blades, a casing havinga concentric conical shield at the inlet side of the fan wheel, and a second concentric conical shield at the outlet side of the fan wheel, stationary vanes. oblique to the axis, between the conical shields and the shell of the easing, an inlet for gas at one side of the fan wheel, an outlet for gas at the other side of the fan wheel, a second outlet for dust at a greater distance from the center than the first outlet, a chamber for settling dust, a

connection from the outlet for dust to the chamber for settling dust.

WILLIAM ANTHONY JONES.

Witnesses: I

BENJ. B. WHITTAM, I HEBER C. Insnnn.