WIND POWER PUMPS.
Windmills can be divided into two general classes according to the inclination of the shaft: 1,Horizontal mills, in which sails are so placed as to turn by the impulse of the wind in a horizontal plane, and hence about an axis exactly vertical; and, 2,vertical mills, in which the sails turn in a nearly vertical plane,i.e., about an axis nearly horizontal.
On account of the many disadvantages connected with the horizontal windmill, it is seldom brought into use, being employed only in situations in which the height of the vertical sails would be objectionable, and this is liable to occur only in extraordinary cases. In this kind of mill six or more sails, consisting of plain boards, are set upright upon horizontal arms resting on a tower and attached to a vertical axis, passing through the tower at its middle part. If the sails are fixed in position, they are set obliquely to the direction in which the wind strikes them. Outside of the whole is then placed a screen or cylindrical arrangement of boards intended to revolve, the boards being set obliquely and in planes lying in opposite courses to those of the sails. The result is, from whatever direction the wind may blow against the tower, it is always admitted by the outer boards to act on the sails most freely in that half of the side it strikes, or from which the sails are turning away, and it is partly, though by no means entirely, broken from the sails which in the other quadrant of the side are approaching the middle line.
Fig. 461.
Fig. 461.
Note.—The great objections to the horizontal windmill are: first, that only one or two sails can be effectually acted upon at the same moment; and, secondly, that the sails move in a medium of nearly the same density as that by which they are impelled, and that great resistance is offered to those sails which are approaching the middle. Hence with a like area of sails the power of the horizontal is always much less than that of the vertical mill.
Note.—The great objections to the horizontal windmill are: first, that only one or two sails can be effectually acted upon at the same moment; and, secondly, that the sails move in a medium of nearly the same density as that by which they are impelled, and that great resistance is offered to those sails which are approaching the middle. Hence with a like area of sails the power of the horizontal is always much less than that of the vertical mill.
The illustration on page 184, Fig.460, is a representation of theCorcoran windmill: it contrasts most interestingly with the same apparatus shown in Fig.459—a windmill of the early part of the 17th century.
The figure below,462, exhibits in detailthe rear view of the Corcoran mill with the governor. As the speed of the wheel increases it swings the “tail” around, so as to bring the wheel at an angle with the direction of the wind; the latter failing to strike the blades squarely communicates less force, and in consequence the speed is diminished; in case of a very high wind the tail turns so as to present the wheel almost edgewise towards the direction of the blast.
Note.—A windmill of this type was erected at a station on the Long Island R. R. to pump 5,000,000 gallons of water yearly. In order to test the work of the windmill, a water meter was attached to the pump during six months, and it was shown that the average work of the windmill had been 22,425 gallons per day, 4,260,750 gallons during the time stated and an average rate of 8,000,000 gallons per year. The weight of water pumped was 16,168 tons gross and was raised to a height of 66 feet, and the work was done without mishap with little attention given to the pumping machinery.
Note.—A windmill of this type was erected at a station on the Long Island R. R. to pump 5,000,000 gallons of water yearly. In order to test the work of the windmill, a water meter was attached to the pump during six months, and it was shown that the average work of the windmill had been 22,425 gallons per day, 4,260,750 gallons during the time stated and an average rate of 8,000,000 gallons per year. The weight of water pumped was 16,168 tons gross and was raised to a height of 66 feet, and the work was done without mishap with little attention given to the pumping machinery.
Fig. 462.
Fig. 462.
Fig.461represents a Corcoran double action suction force pump. The base is hollow and contains the suction and discharge valves; a flange at the left-hand side receives the suction pipe while a corresponding flange on the right-hand side connects with the discharge pipe. An air chamber is attached tothe discharge end. The valves may be reached by removing the bonnets on top of the base.
Fig. 463.
Fig. 463.
Fig.463is intended to represent anIdeal steel tank tower; the tank is herein located near the top. Aforce pumpis used where water is delivered into an elevated tank as in this case; alift pumpis employed to discharge water at the spout and not to elevate above it.
The common term “Windmill pump” distinguishes a wind power pump from a hand pump, the difference being in an extension of the piston rod above the upper guide with a hole for connection with the pump rod from the windmill.
Such a pump, with the “pit-man” extending from the pump upwards into the tower, is shown in Fig.465. This figure is introduced to show the tank connections with a regulator on the base of a four-post tower. The float in the water tank throws the mill in or out of gear according as the water rises or falls in the tank.
When the tank is filled with water it pulls the mill out of gear and stops the pump; as a result there can be no overflow or waste. The tank is thus not allowed to become empty and permit its drying apart, inducing leakage. But through the medium of the float in the tank, when the water has been lowered but a few inches, the mill is again put in gear and the tank refilled to the desired height, at which the float is set.
Note.—These have long been erroneously termedwindmill pumpsdating to the time when wind furnished the power for drivingthe grist mills used in grinding grain, etc.More properly they may now be namedwindmotorsorairmotors.
Note.—These have long been erroneously termedwindmill pumpsdating to the time when wind furnished the power for drivingthe grist mills used in grinding grain, etc.More properly they may now be namedwindmotorsorairmotors.
The syphon pumphere illustrated, Fig.464, is used to force water from shallow wells to elevations. The cylinder or barrel is situated within the standard and very convenient for inspection. It has an air chamber which is detachable.
Fig. 464.
Fig. 464.
The subject of tanks and cisternsis one almost vital to the successful operations of ordinary windmills, owing to the irregularity of the power to be utilized by the use of aermotors.
In another part of this work this important subject will be further explained and illustrated.
One of the most valuable special features of this windmill is its governor.It is so contrived that it insures immunity of the mill from injuries in destructive storms. It consists of a steel coiled spring of great resiliency, located at the base of the vane frame. Its strength is of such a character as to hold the wheel in the teeth of the wind under all ordinary conditions but is sure to yield under greater pressure.
Fig. 465.
Fig. 465.
USEFUL DATARELATING TO THE SIZES AND CAPACITIES OF PUMPING MILLS.
Table I.
Size ofPumping Mill6891012141620No. Gals.water raised1 ft. hourly,15-mile wind10,00020,00024,00035,00068,000110,000160,000300,000
Table II.
Average wind velocity, miles per hour456789101112131415Co-efficient1685321.41..85.70.60.54.50
Average wind velocity, miles per hour
Table III.
Gallons hourly35170220260300360420Cylinder, diam. in.221⁄421⁄223⁄4331⁄431⁄2Discharge pipe, diam. in.11⁄211⁄411⁄411⁄211⁄222Gallons hourly5508501200220034005000Cylinder, diam. in.45681012Discharge pipe, diam. in.221⁄221⁄231⁄245
Table IV.
COMPARATIVE POWER OF BACK-GEARED MILLS.Size of Mill4-ft.6-ft.8-ft.9-ft.10-ft.12-ft.14-ft.16-ft.Horse-Power1⁄121⁄53⁄102⁄53⁄5113⁄523⁄5
Table V.
FORCE OF THE WIND IN POUNDS PRESSURE.VelocityMiles810121520253040ForcePounds1⁄31⁄23⁄412341⁄28
Table VI.
POWER OF THE WIND.Velocity per Hour.Pressure per Sq. Foot.10 Miles1⁄2Lb.15 „1 „20 „2 Lbs.25 „3 „
Table VII.
GROSS AND EFFICIENT POWER OF 12 AND 14 FOOT WINDMILLS.SIZE OF MILL.Velocityof Wind.GrossHorse-power.NetHorse-power.12-Foot Ideal Power Mill10 Miles1⁄21⁄1012 „ „ „ „15 „13⁄512 „ „ „ „20 „213⁄512 „ „ „ „25 „323⁄514 „ „ „ „10 „13⁄514 „ „ „ „15 „213⁄514 „ „ „ „20 „433⁄514 „ „ „ „25 „653⁄5
The preceding tables are based upon tests of theSampson windmillas compiled by its makers, The Stover Manufacturing Co.; they deserve careful study by those planning the introduction of aermotors.
The power of a windmilldepends—first, on the diameter of the wheel; and second, on the velocity of wind.To increase the diameter of the wheel is to increase its powerin proportion to the area of the squares. Table I gives the horse-power of several sizes of mills working in a fifteen-mile wind: if the wind velocity be increased or diminished, the power of the windmill will increase or decrease in the ratio of the squares of the velocity. Table V will show the comparative power or force of the wind in velocities from eight to forty miles per hour for each square foot of surface.
Rules for approximately determining size of windmill to use.
The daily water consumption must be given as a basis for calculation. Divide this by 8 to find the hourly capacity of windmill, as if loaded aright the mill will pump on an average eight hours daily.
Multiply the quotient by total water lift in feet and with the co-efficient given in Table II.
The product will in Table I show what mill to use.
The size of the cylinder and discharge pipe will be found in Table III.
Fig. 466.
Fig. 466.
Table I gives the maker’s number of the pumping mill, and the number of gallons each will raise one foot high per hour, with a wind having a velocity of fifteen miles per hour. Example: No. 9 pump will raise 24,000 gallons of water one foot high in one hour. Now if the water is to be raised 50 feet then by dividing 24,000 by 50 the quantity raised becomes 480 gallons per hour.
From Table V it will be seen also that a wind velocity of fifteen miles per hour develops a power three times as great as an eight-mile wind, and a twenty-mile wind is twice as powerful as a fifteen-mile, or six times that of an eight-mile. Hence,a small increase in velocity greatly increases the power of the windmill, while a low velocity gives but little working force.
From Table VI it is seen that a twenty-five mile wind gives six times as much power as a ten-mile wind, but really gives twenty-six timesthe net efficient power of the ten-mile wind, therefore it will not be proper to calculate on using a power windmill in as low a velocity as ten miles.
From Table VII it is seen that the net efficient result is six times as great in a fifteen-mile wind as in a ten-mile wind, and sixteen times greater in a twenty-mile wind than in a ten-mile wind. Therefore,power windmills give best results when working in fifteen to twenty-five mile winds. A 12-foot power windmill working in a fifteen-mile wind will do more work than an average horse, and when working in a twenty-mile wind will do more work than two average horses.
Example.—A person in Atlanta, Ga. uses 2,600 gallons of water daily. He has a well in which the water stands 30 feet from ground level. To obtain pressure, the water is to be elevated into a tank 50 feet above ground. 2,600 ÷ 8 = 325 gallons to be pumped hourly when windmill works.Average wind velocity at Atlanta is 9 miles per hour, answering to coefficient 1.4 in Table II, and total water lift is 30 + 50 = 80 feet. 325 × 1.4 × 80 = 36,400 gallons.If first estimate of 2,600 gallons daily was liberal, so that for instance 2,400 gallons would be sufficient, Table I shows that a 10-foot mill can be used, but to keep on the safe side, choose a 12-foot mill. 325 gallons hourly gives us in Table III 31⁄4-inches cylinder with 2-inches discharge pipe as proper sizes. If the 10-foot mill is chosen take the 3-inch cylinder.
Example.—A person in Atlanta, Ga. uses 2,600 gallons of water daily. He has a well in which the water stands 30 feet from ground level. To obtain pressure, the water is to be elevated into a tank 50 feet above ground. 2,600 ÷ 8 = 325 gallons to be pumped hourly when windmill works.
Average wind velocity at Atlanta is 9 miles per hour, answering to coefficient 1.4 in Table II, and total water lift is 30 + 50 = 80 feet. 325 × 1.4 × 80 = 36,400 gallons.
If first estimate of 2,600 gallons daily was liberal, so that for instance 2,400 gallons would be sufficient, Table I shows that a 10-foot mill can be used, but to keep on the safe side, choose a 12-foot mill. 325 gallons hourly gives us in Table III 31⁄4-inches cylinder with 2-inches discharge pipe as proper sizes. If the 10-foot mill is chosen take the 3-inch cylinder.
A 14-foot windmill working in a fifteen-mile wind will do more work than two average horses, and when working in a twenty-mile wind will do more work than four good horses, while in a twenty-five mile wind it will do more work than six good horses.
Giving the above tables a practical application, a little thought will disclose what a wealth of power stands unappropriated and ready at hand to do many of the drudgeries of work for which large expenditures are annually made.
The uses of power windmills are so well understood that it seems out of place to elaborate upon them; the brief space allowed to giving information as to the power of this class of mills when working in different wind velocities, is best expressed in tabular form, Table VI.
Fig.466represents the working barrel of adeep well pump, such as are used frequently in connection with the larger sizes of aermotors.
The tube is usually made of heavy brass—this isdrawnso perfectly, as to size and smoothness, that a re-boring is not needed.
The plunger is here shown with four cup leather packings, with one ball valve; the bottom valve is also a ball with the seat resting within a conical coupling at the bottom, this with a leather packing makes a water tight joint.
Should any accident happen to the bottom valve it may be withdrawn by lowering the sucker-rod until the threaded portion comes in contact with the nut underneath the plunger. By turning the sucker-rod the nut engages the thread on the top of the lower valve-cage. Then by withdrawing the sucker-rod both valves may be drawn up for examination or repairs.