US1811898A - Metering apparatus - Google Patents

Description

June 30, 1931. SCQUR T L 1,811,898

METERING APPARATUS Filed Sept. 18, 1928 4 Sheets-Sheet 1' 772222 a 50km",

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Patented June 30, 1931 UNITED STATES PATENT OFFICE MILTON 0. SCHUR AND ERNEST P. COOK, OF BERLIN, NEW HAMPSHIRE, ASSIGNORS TO BROWN COMPANY, OF BERLIN, NEW HAMPSHIRE, A CORPORATION OF MAINE METERING APPARATUS Application filed September 18, 1928. Serial No. 306,674.

This invention relates to apparatus for paring pulp stock for various ultimate uses,

the stock has to be treated with chemicals. The proportions of chemicals to the dry weight of the fiber in the stock must in many cases be accurate within narrow limits of error; hence to ensure correct proportioning. it is essential that the consistency of the stock (i. e. the percentage of pulp by weight in the stock) be accurately known, and preferably kept constant, and that the stock be supplied at a known and preferably constant rate. The. present invention is concerned with the latter problem, namely, the supplying of pulp stock at an accurately known rate which can preferably be regu- Mechanisms heretofore devised for the same purpose are in general unreliable in practice, especially when used with stock which is relatively. thick or which contains unbeaten fibers. Our improved apparatus op'erates successfully with pulp stock of any concentration Within the range of ordinary mill practice even when the fibers have had little or no beating.

In carrying out our invention, we may provide a rotatable paddle wheel with compartments of known capacity between suc cessivc paddles. The paddle wheel is arranged so that no matter how sluggish the stock may be, the successive compartments are completely filled with stock as the padincoming stock. This arrangement ail'ords pastthe paddles as is hereinafter described.

It is also possible to employ a paddle rotated about a vertical axis provided the stock be supplied thereto in a manner to be later described.

For a more complete understandin invention, reference is had to the description which follows, and to the drawings of which,

Figure 1 is a longitudinal section of an embodiment of the invention taken on the line 11 of Figure 6.

Figure 2 is a portionof Figure 1 showing a modified form of paddle.

Figures 3 and 4 show a portion of Figure 1 with the paddle wheel in difl'erent positions of operation.

' Figure 5 is a side elevation of apparatus embodying the invention.

Figure 6 is a section on the line 66 of Figure 5. i

Figure 7 is a section on the line 7+7 of Figure (5.

Figure 8 is a section on the line 88 of Figure 7. v

Figure 9 is a sectional View of a moditie form of apparatus, the section being taken on the line 9-9 of Figure 10. v

Figure 10 is a horizontal section on the line 10-l0 0f Figure 9.

Figure 11 is a fragmentary section showing a detail of the structure illustrated; in Figures 9 and IQ Referring the the drawings in detail, the

of the apparatus illustrated in Figure 1' includes maintain the liquid in the tank at a substantially constant level, the orifice of the pipe 21 may be fitted with a butterfly valve 22 which may be regulated as by a suitable float 23 in a manner well known in the art. Preferably adjacent to an end of the container 20 is an outlet pipe 24 which leads from a discharge receptacle or compartment 25. The floor 26 of the tank 20 is connected to the wall of the discharge receptacle 25 as by an areuate wall 27 which is concentric with the axis of a suitable paddle wheel 28 mounted to rotate on a horizontal axis.

The paddle wheel 28 may be constructed with any desired number of paddles 44;, four of these paddles being shown in the wheel illustrated in Figure 1. The outer edges of the paddles 29 are preferably provided with sealing strips 30 of rubber or other suitable material, the paddle wheel being located with reference to the arcuate surface 27 so that the sealing strips 30 will rub against the surface 27 and will prevent passage of the liquid from the tank 20 to the discharge receptacle 2:) except for that which is contained in the compartments or chambers 31 between successive paddles 44. The ends of the paddle wheel are preferably provided with sealing means to prevent leakage of liquid from the tank 20. To this end we may conveniently employ a construction illustrated in Figure 6, the paddle wheel 28 being provided with disc like heads or end members 32. These heads effectually- 'prevent leakage of liquid from one compartment to another. In order to avoid leakage past the rims of these head members 32, we may provide arcuate channels 33 secured to the side Walls 34 of the tank 20, as shown in Figure 7.

The channels 33 are each provided with a suitable groove 35 adapted to receive a packing strip 36 of leather or other suitable 1naterial for the purpose. This strip 36 may be secured in place as by a series of pins 37, a portion of the strip being within the groove 35, and a portion projecting therefrom for rubbing engagement with the rim of the paddle wheel head 32. In order to maintain the packing strip 36 in snug engagement with the rim of the head 32, we may provide a thin, flexible strip 33 of metal or the like, this strip being positioned in the groove 35 beneath the packing strip 36. The lower end of said strip 38 may be anchored as by a pin 39. The upper end may be secured to a threaded member 40 passing through a fixed plate 41 carried by the channel member 33, a nut 12 being threaded on the outer end of the member -10. As shown in Figure 7 rotation of the nut 42 draws up the slack of the band 38 sothat the pressure of the packing strip 36 against the rim of the head member 32 may thus be conveniently regulated. This effectively seals the apparatus against leakage without danger of jamming or binding. The compartments 31 are of known capacity so that by rotating the paddle wheel 28 in a counterclockwise direction as shown in Figure 1, each revolution of the wheel will result in the filling and emptying of four coinparaments, the compartments being filled with liquid from the tank 20 which is thereupon discharged into the receptacle 2:"). By rotating the wheel 23 at a known speed, the rate of discharge of liquid from the tank can be accurately determined.

When dealing with viscous or sluggish liquids it is difiicult with some types of apparatus to ensure the complete filling of the compartments between successive paddles, quantities of air being frequently entrapped in the compartments due to the sluggishness of the liquid. This difficulty is effectively avoided by the arrangement of paddle wheel 28 to rotate. on a horizontal axis toward the flow of liquid supplied thereto. The liquid enters each fillcctsisivt compartment as shown in Figures 3 and 4 and there is no opportunity for air to become entrapped, even when the liquid is so viscous as to be in the nature of a semiplastic as is the case with relatively concentrated suspensions of unbeaten cellulosic fiber.

The paddles '44.- of the Wheel 28 may be shaped as shown in Figures 1, 3 and 1, each paddle having a rear face 43 which is convex to conform approximately to the natural flow of the liquid entering a compartment. The front or advancing face of each paddle may have a concave-convex surface so that as the outer portion of each paddle swings around to the level of the liquid in the tank 20, as shown in Figure 4, the face of the paddle will not incline over the surface of the liquid. Thus there is no possibility of entrapping .air in the compartment. Instead of the specific form of paddle illustrated in Figure 1, other forms may be employed such as the plane paddles 29 illustrated in Figure 2.

In order to regulate the rate of discharge of liquid from the tank 20, it is necessary that the paddle wheel 28 be rotated at a definite predetermined speed. To this end. as indicated in Figure 5, an electric motor 45 or other suitable source of power may be connected to the Wheel through any desired gearing. This motor may be connected through a small gear box 46 and a large gear box 47 to the wheel 28, the gears in the boxes being shifted by suitable control handles 48, 4.9, respectively. The boxes 46, 47 may contain a set of gears selectively connectible to utilize different reduction ratios in a manner well known in the art. By combining the reduction in one gear box with that in the other, a wide variety of speeds of rotation of the wheel may be obtained. In order to its orifice.

avoid injury to the gears in the boxes 46, 47, a brake 50 may be provided on the drive shaft from the motor, this brake being operated by a magnetic device 51 adapted to stop quickly the rotation of the motor 45 whenever the handle 48 or 49 is operated to shift gears, the releasing of the handle 48 or 49 also being arranged to shut off the current automatically from the motor 45 and the brake 50, permitting the brake to stop the deenergized motor quickly in a manner well known in the art.

A modified embodiment of the invention is illustrated in 1*igures 5) and 10 wherein is shown a suitable tank or container 52. This tank may be provided with a partition 53 having an opening in which is mounted a suitable paddle wheel 54 for rotation on a vertical axis. In order to prevent a free opening through the partition 53 at any stage of rotation of the wheel 54, we may provide an upper plate 55 for rubbing enga ement with the u ))tl ed es of the I" Z paddles 56 and a lower plate 57, for engagement with the lower end edges of the paddles 56, the plate 57 preferably being in the form of an extension of the floor 58 of the tank 52. For the same purpose a pair of arcuate side plates 53) are mounted on the partition 53, these side plates being concentric with the axis of the wheel and adapted to be engaged by the outer edges of the successive paddles 56 as the wheel rotates. The side plate 59 each extend through an are approximately 90 degrees. As these side plates are symmetrically arranged, the space between them opens out on'one side to the compartment 67 and on the other side to the 1 central compartment of the vat so that stock may flow freely from the vat to the compartments between the successive paddles 5b which are presented in turn as the paddle wheel rotates. \Vhen operating with extremely sluggish liquids such as relatively concentrated suspensions of cellulosic pulp fiber, considerable difliculty may be experienced in completely filling the successive compartments between the paddles 56 owing to the liability of air becoming entrapped under the top plate 55. lVhen air is thus entrapped the amount of liquid carried around and-discharged by each compartment thus becomes indeterminate and the value of the apparatus as an accurate metering device is largely lost. To ensure the. complete filling of each compartment as it is presented to the liquid in the tank 52, We prefer to introduce the supply of liquid for the tank 52 through the bottom there of at a point closely adjacent to the axis of the wheel 54. As shown in Figures 9 and 10 the inlet pipe 6U is so arranged that the compartments or chambers of the paddle wheel pass directly over Thus the supply of pulp for the tank 52 is forced directly into the successive I compartments of the wheel and the flow of liquid under gravity alone is not depended upon to fill the compartments. In order to permit the ready escape of air from the upper portion of each compartment, a suitable opening 61 is formed in the upper plate 55, this opening being preferably directly above the orifice of the supply pipe so that the flow of liquid entering through the pipe 60 forces the liquid up through each successive compartment until the compartment is full, whereupon any excess liquid ma flow up and out through the hole 61. In order to maintain the liquid in the tank at the proper level, that is, at least up to the plate 55, we may provide a suitable dam or partition 62 over which excess liquid may spill as shown in Figure 9 into an outlet pipe 63. If desired, a suitable splash plate 64 may be mounted directly above the opening 61. The paddles 56 are preferably provided along their outer edges with sealing flaps 65, and similar flaps 66 may be mounted along the upper and lower edges of the paddles to rub against the upper and lower plates. As each compartment fills it is rotated into a discharge receptacle 67 at the end of the tank 52 beyond the partition when the discharged liquid flows out through a suitable pipe 68.

\Ve claim:

1. Apparatus of the class described comprising a container for liquid, a discharge receptacle, and means'ior conveying fluid from said container to said discharge receptacle. at a predetermined rate, said means comprising a paddle wheel having equispaced paddles and mounted. for rotation on a horizontal axis, an arcuate wall concentric with said axis and extending from the bottom of said container to said discharge receptacle, said wall being engageable successively by the outer edges of the paddles and being of sufficient arcuate length to be engaged by two paddles simultaneously, means for preventing leakage around the edges of the paddles when in contact with the wall, and means for rotating the wheel at a predetermined speed 2. Apparatus of the class described comprising a liquid container having side walls and a bottom, a discharge receptacle adjacent one end of said container, an arcuate tion of said wheel, means for. rotating said wheel at a predetermined speed and means for preventing leakage of liquid past the heads of the wheel and the edges of the paddles. 7

3. Inapparatus for discharging sluggish liquid at a predetermined 'rate, a paddle Wheel mounted for rotation on a horizontal axis, said Wheel having paddles with concavo-convex front faces and convex rear faces.

In testimony whereof We have aflixed our signatures.

MILTON O. SCHUR. ERNEST P. COOK.

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