US2974834A - Stock meter - Google Patents

Description

March 14, 1961 J. E. FOOTE ETAL STOCK METER Filed Sept. 15, 1959 M8 mm w N QC 0E w w m 5 M s K C 3 E w. H. mv a? f l 9 0w 5. m mm 8 C M mm m MW N.? I A u I mw K I Y B |||l N I g I mm ()0- mm m.

ATTORNEY United States Patent STOCK METER Filed Sept. 15, 1959, Ser. No. 840,054

8 Claims. (Cl. 222-356) This invention relates to stock meters, and more particularly to apparatus for dispensing metered quantities of liquid stock. Although apparatus embodying the invention is capable of dispensing and metering various types of liquid stock, it is particularly applicable for supplying liquid pulp slurry to pulp molding machines, especially for pulp stock of high consistency, wherein a relatively high ratio of pulp fibers to liquid is present therein.

Stock meters are customarily employed for regulating the rate at which pulp slurry stock is supplied to pulp molding machines, since it is desirable to supply the stock at a rate of flow commensurate with the rate of production of the molding machines. Usually, such meters have comprised gate valves or suitable throttling devices mounted in the stock supply pipes, and sometimes such meters have involved relatively movable, slidably interfitting elements. When pulp stock of high consistency was metered in such devices, difficulty was frequently encountered with a tendency of the devices to become clogged by deposited pulp fibers. In contrast with the free-flowing characteristics of highly dilute pulp stock, which may contain only about 1% to 2% by weight of pulp fibers, pulp stock of relatively high consistency, which may contain as much as about 5% by weight of pulp fibers, exhibits a natural tendency to deposit pulp fibers in conglomerate mounds about any restrictive openings through which the stock must flow. Particularly in the case of metering devices having relatively movable, slidably interfitting parts, the pulp fibers deposited from high consistency stock sometimes cause jamming of the stock meter, and consequent shutdown of the entire pulp molding machine.

An object of the present invention is to provide a new and improved stock meter.

' Another object of the invention is to provide a new and improved device for dispensing and metering liquid stock.

Still another object of the invention is to provide a new and improved stock meter for supplying pulp slurry stock to pulp molding machines.

Yet another object of the invention is to provide a new and improved stock meter for supplying liquid pulp stock of relatively high consistency to pulp molding machines, which meter is constructed without relatively movable, slidably interfitting elements in contact with the stock, to avoid the danger of jamming such parts by deposited pulp fibers.

' Other objects and the nature and advantages of the instant invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a vertical sectional viewof a stock meter embodying the invention, shown at one stage of its operation; and

- Fig. 2 is a view corresponding to Fig. 1, showing the stock meter at another stage of its operation.

In accordance with the present invention, the stock meter illustrated in the drawings includes a generally ice rectangular reservoir 10 adapted to contain a substantial quantity of pulp slurry stock of relatively high consistency, which may comprise a homogeneous suspension of at least about 5% by weight of pulp fibers in water. The reser voir 10 may have an open top portion 12, and it is provided with aninlet stock supply pipe 14, which may be mounted at one side thereof and submerged below the upper level of the stock contained therein. The pulp stock is maintained within the reservoir 19 at a predetermined constant level therein controlled by a vertically adjustable darn or weir 16 mounted at one side of the reservoir 10 adjacent to an overflow compartment 18, which is attached to the reservoir 10 near its upper portion 12. Pulp stock is constantly pumped into the reservoir 10 through the inlet pipe 14 from a suitable source of supply (not shown),

and any more stock than is needed to maintain the predetermined constant level Within the reservoir 10 overflows the weir 16 into the overflow compartment 18, from which it is drained away through an overflow pipe 20 and returned to said source of supply.

A tubular measuring receptacle 22, which is preferably cylindrical in configuration, is disposed vertically and movably mounted centrally within the reservoir 10 for vertical reciprocation therein. The receptacle 22 is provided with an open upper end 24 secured to a semicircular bail 26, which is connected to a vertical piston rod 28 extending downwardly from a piston head 3% mounted on the top portion 12 of the reservoir ill. The piston rod. 28 is vertically slidable through a guide plate 32 mounted within a bracket 34 which supports the piston head 30 on the top portion 12 of the reservoir 10. Vertical reciprocation of the receptacle 22 by actuation of the piston head 30 causes the open upper end 24 of this receptacle to be moved alternately between an emerged position and submerged position, with respect to the predetermined constant level of the pulp stock maintained within the reservoir 10. In this manner the receptacle 22 is allowed to become filled with the pulp stock during each downstroke of its reciprocal movement.

The tubular measuring cylinder 22 is also provided with an open bottom end 36 terminating in an annular beveled valve seat 38, which is adapted to cooperate with a resiliently mounted, vertically movable valve 41) POSl: tioned directly therebelow. The valve 40 is mounted Within a discharge chamber 42, which is relatively smaller than the reservoir 10 and is secured centrally to the bottom thereof, so as to be directly underneath the vertically movable measuring receptacle 22. An annular, flexible, liquid-impervious diaphragm 44, preferably composed of natural or synthetic rubber, is secured to and extends between the open lower end 36 of the receptacle 22 and a surrounding horizontal bottom wall portion 46 of the reservoir 10. The diaphragm 44 in effect constitutes a continuation of the bottom wall 46 of the reservoir 10, and the diaphragm is provided with a central aperture 45 through which the lower end 36 of the receptacle 22 projects, so that this diaphragm forms a liquid-tight sealed partition between the reservoir 1t? and the discharge compartment 42.

An important feature of the present invention is the fact that the flexible diaphragm 44 constantly maintains a liquid-tight seal between the reservoir 10 and the discharge chamber 42 during the entire reciprocatory movement of the measuring receptacle 22, and this construction avoids reliance upon slidably interfitting, relatively movable parts, which would have an attendant undesirable tendency to become jammed by deposited pulp fibers when stock of high consistency is being metered. Thus, if the vertically reciprocable receptacle 22 merely projected through a rigid aperture in the bottom wall 46 of the reservoir 10, or if a pair of telescopically slidable tubes were used in place of the valve seat 38 and the valve 41), then the hazardof having such jamming of the relatively movable parts by deposited pulp fibers would inevitably be present.

The valve 40 is mounted on the upper end of a verti c'ally disposed and movable valve stem 48, which projects through a central aperture 49 in the bottom wall of the discharge compartment 42. An adjustable stop nut 50 is mounted in threaded engagement with the stem 48 for longitudinal movement therealong to limit the extent of vertical movement of the valve stem 48 and a helical compression spring 52 surrounding the stem 48 extends between the valve 40 and the bottom wall of the discharge compartment 42, thereby normally urging the valve 40 upwardly to the maximum extent permitted by engagement of the nut 50 with the sides of the aperture 49 in the bottom of the discharge chamber 42. An annular skirt 54 extends downwardly from the outer periphery of the valve 40 and fits telescopically in sliding engagement over an annular flange 56 which projects upwardly from the aperture 49 in the bottom of the discharge chamber 42. The skirt 54 and the flange 56 together constitute a housing concentrically surrounding the valve stem 48, and they function as a guide for the vertical reciprocatory movement of the valve 40. The telescopically interfitting skirt 54 and flange 56 are kept out of contact with the liquid pulp stock to prevent them from becoming jammed by any pulp fibers deposited from the stock, by means of a second annular flexible diaphragm 54 which is secured to and extends between the skirt 54 and the bottom of the discharge chamber 42, so as to maintain a liquid-tight partition therebetween. A discharge pipe 60 is provided at one side of the bottom of the discharge chamber 42 for communication with a pulp molding machine (not shown) being provided with a controlled quantity of pulp stock by the stock meter.

Operation In operation, actuation of the piston head 30 causes the tubular measuring cylinder 22 to be reciprocated vertically alternately between its elevated emerged position, shown in Fig. l, and its lowered submerged position, shown in Fig. 2. In its fully elevated position, the measuring receptacle 22 is empty, being open at both its upper end 24 and its lower end 36. On the downstroke of its reciprocatory movement, the receptacle 22 is moved downwardly until its upper end 24 is submerged below the constant predetermined level of liquid pulp stock within the reservoir 19, which level is maintained by constantly pumping fresh pulp stock into the reservoir through the inlet pipe 14 and allowing any excess stock to overflow the vertically adjustable darn or weir 16 into the overflow compartment 123. Just before the receptacle 22 becomes submerged in the liquid pulp stock, the annular beveled valve seat 38 on the open lower end 36 of this receptacle is brought into liquid-sealing contact with the resiliently mounted valve 4!). Continued downward movement of the receptacle 22 carries the valve 49 downwardly to the limit ofthe stroke of the piston head 3%, or until the downward movement of the valve 49 is stopped by engagement thereof with the annular flange 56 projecting upwardly from the bottom of the discharge chamber 42. in its one lowermost submerged position, the receptacle 22 becomes filled with the liquid pulp stock by allowing the stock to flow freely into the open upper end 24 of the receptacle While its lower end 36 is closed by the valve 40.

On the upstroke of the cylindrical measuring receptacle 22, which is now filled with liquid pulp stock, just after the upper end 24 of the receptacle 22 emerges above the constant upper level of the pulp stock in the reservoir 10, the lower end 36 of the receptacle 22 is opened by movement of the valve 49 away from the valve seat 38, thereby allowing the contents of the receptacle 22 to flow downwardly into the discharge chamber 42 and thence outwardly through the discharge pipe 60 to the pulp molding machine (not shown) being supplied with liquid pulp stock by the stock meter. At the beginning of the upstroke of the receptacle 22, the valve 40 moves along with it under the urging of the helical compression spring 52, and thus keeps the lower end 36 of the receptacle 22 closed during the initial portion of its upward movement. Upward movement of the valve 40 continues until the adjustable stop nut 50 is carried upwardly by the valve stem 43 into engagement with the sides of the aperture 49 in bottom of the discharge chamber 42, which action halts the upward movement of the valve 4%. As the receptacle 22 continues the upward stroke of its reciprocatory movement while the valve 45} is thus prevented from continuing to travel upwardly along therewith, the valve seat 38 thereby becomes separated from the valve 40, and thus opens the lower end 36 of the receptacle 22.

Repetition of the above described cycle of operations by continued vertical reciprocation of the tubular receptacle 22 supplies the pulp molding machine with a succession of measured quantities of liquid pulp stock, each of which quantities is equivalent to the internal volume of the measuring receptacle 22. Preferabl the piston head 39 is actuated in timed relationship to the operation of the pulp molding machine to supply said machine with a controlled quantity of pulp stock commensurate with the production rate of the machine.

It is particularly important to observe that the annular flexible diaphragm 44 constantly maintains a liquid-tight sealed partition between the reservoir 10 and the discharge chamber 42 during the entire reciprocatory movement of the cylindrical measuring receptacle 22, The flexibility of the diaphragm 44 enables its inner edge to move with the reciprocating receptacle 22, while its outer edge remains anchored to the bottom wall 45 of the reservoir 10. Likewise, the flexible diaphragm 58 has one of its edges secured immovably to the bottom of the discharge chamber 42, while the other edge of the diaphragm 58 is joined to and movable with the skirt 54 extending downwardly from the valve 40. These flexible diaphragms advantageously prevent the liquid pulp stock from contacting any slidably interfitting apparatus elements, which might become jammed by pulp fibers deposited from the stock, especially from stock of high consistency. Stock meters embodying the present invention are capable of operating efliciently the pulp stock of rela tively high consistency, which may containas much as about 5% by weight of pulp fibers, without the necessity of periodically shutting down the apparatus to clean out jammed movable elements.

Although only a single embodiment of the invention has been illustrated and described, it will be obvious to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention, and therefore the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

V 1. A stock meter, comprising a reservoir adapted to contain liquid stock, means for maintaining the stock at a predetermined level within the reservoir, atubular measuring receptacle mounted movably within the reservoir and having normally open upper and lower ends, means for vertically reciprocating the receptacle alternately between an emerged position in which its open upper end is elevated above the level of the liquid stock in the reservoir and a submerged position in which said end is lowered below the level of the stock, a discharge chamber mounted below the receptacle for receiving the liquid stock therefrom, a valve cooperating with the open lower end of the receptacle for closing said end when thereceptacle is in its submerged position and, opening said end when the receptacle is in its emerged position, and a flexible partition secured to both the receptacle and the reservior and v extending between the reservoir and the discharge chamher, said partition flexing during reciprocation of the receptacle and to maintain a liquid tight seal between the reservior and the discharge chamber.

2. The stock meter defined by claim 1, wherein the partition is a flexible, liquid-impervious diaphragm secared to and extending between the lower end of the receptacle and the bottom of the reservior.

3. A stock meter, comprising a reservoir adapted to contain liquid stock, means for maintaining the stock at a predetermined level within the reservoir, a tubular measuring receptacle having normally open upper and lower ends disposed vertically within the reservoir and reciprocable vertically therein, means for vertically reciprocating the receptacle alternately between an emerged position in which its open upper end is elevated above the level of the liquid stock in the reservior and a submerged position in which said end is lowered below the level of the stock, a discharge chamber mounted below the receptacle for receiving the liquid stock therefrom, a valve mounted movably within the discharge chamber below the open lower end of the receptacle, said valve closing the open lower end of the receptacle when the receptacle is in its submerged position and opening said end when the receptacle is in its emerged position, and a flexible diaphragm forming a liquid-tight partition between the reservoir and the discharge chamber, said diaphragm having an aperture through which the lower end of the receptacle projects into the chamber and to which said end is secured so that said diaphragm is flexed during the vertical reciprocation of the receptacle.

4. The stock meter defined by claim 3, wherein the valve is reciprocable vertically, and it is normally urged upwardly toward the receptacle by a compression spring mounted in the bottom of the discharge chamber.

5. The stock meter defined by claim 3, wherein the valve is secured to the upper end of a vertical stem mounted movably in the discharge chamber and reciprocable vertically for movement with the measuring receptacle during a portion of its reciprocatory movement, an adjustable stop is mounted on the stem for limiting the movement of the stem, and a spring mounted on the stem urges the value upwardly toward the receptacle.

6. The stock meter defined by claim 5, wherein said stem and spring are housed within an annular flange projecting upwardly from the bottom of the discharge chamber, an annular skirt depending from the valve fits telescopically in sliding engagement over said flange, and a second flexible diaphragm forms a liquid-tight partition between said skirt and the bottom of the discharge chamber.

7. A stock meter for supplying measured quantifies of liquid pulp slurry stock to pulp molding machines, comprising a reservoir adapted to contain liquid pulp stock, means for maintaining the stock at a predetermined constant level within the reservoir, a tubular measuring receptacle having normally open upper and lower ends disposed vertically within the reservoir and reciprocable vertically therein, a piston secured to the receptacle for vertically reciprocating it alternately between an emerged position in which its open upper end is elevated above the level of the pulp stock in the reservoir and a submerged position in which said end is lowered below the level of. the stock, a discharge chamber secured to the reservoir directly below the receptacle for receiving measured quantities of the stock therefrom, a flexible diaphragm forming a liquid tight partition between the reservoir and the discharge chamber, said diaphragm having an aperture through which the lower end of the receptacle projects into the chamber and to which said end is secured so that said diaphragm is flexed during vertical reciprocation of the receptacle, a vertically movable valve mounted resiliently within the discharge chamber directly below the open lower end of the receptacle and movable therewith during a portion of its reciprocatory movement, said valve closing the I open lower end of the receptacle when the receptacle is in its lowered submerged position and opening said end when the receptacle is in its elevated emerged position, a telescopically movable guide extending between the valve and the bottom of the discharge chamber for controlling the movement :of the valve, and a second flexible diaphragm forming a liquid-tight partition between said guide and the bottom of the discharge chamber.

8. The stock meter defined by claim 7, wherein the telescopically movable guide comprises an angular flange projecting upwardly from the bottom of the discharge chamber, and an annular skirt extending downwardly from the valve fits telescopically in sliding engagement over said flange, said second flexible diaphragm having an aperture into which the lower end of said skirt fits in liquid-tight engagement to form a liquid-tight partition between said guide and the bottom of the discharge chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,534,997 Smith Dec. 19, 1950

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