US445223A

US445223A - Filter

Info

Publication number: US445223A
Authority: US
Publication date: 1891-01-27
Anticipated expiration: 1908-01-27

Description

(No Model.)

' E. M. KNIGHT.

FILTER.

2 Sheets-Sheet 1.

Patented Jan. 27,1891.

"me Nunma PETERS cm. muro'u'mo wAsmNaTon, n. c,

(No Model.) 2 S11eetsSheet 2. E. M. KNIGHT.

NITED STATES PATENT OFFICE.

EDlVARD ML KNIGHT, OF SAN FRANCISCO, CALIFORNIA.

FILTER.

SPECIFICATION forming part of Letters Patent No. 445,223, dated January 27', 1891.

Application filed May 8, 1890, Serial No. 351,069. (No model.)

To all whom, it may concern:

Be it known that I, EDWARD M. KNIGHT, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvementin Filters; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to that class of filters in which a fibrous or porous material is employed to support the filtering medium; and it consists in certain devices and details of construction, which will be more fully described hereinafter.

Referring to the accompanying drawings for a more complete explanation of my invention, Figure 1 is a view of one of my filter sides. Fig. 2 is a view of the frame of the same. Fig. 3 is front view of the outer tank or casing partly broken away, showing the interior arrangement of the different parts. Fig. 4 is a lateral vertical cross-section through the casing, and also one of the filter-sections.

In my former patent, dated January 14, 1890, No. 419,266, I have shown a fibrous surface to support the filtering medium stretched over an interior frame-work and an exterior cover of wire screen-work which is designed to uphold the filtering medium which is applied to the outside of the fibrous covering. In practice I have found that it is impossible to stretch the fibrous covering sufficiently tight to prevent its sagging away from the exterior screen, and this allows the filtering medium, which is composed of a charcoal paste, to peel and fall off from the fibrous covering.

In my present invention I apply a backing of wire-cloth or finely-perforated sheet metal, over which the fibrous material is stretched and secured by a device to be hereinafter de scribed.

The filtering medium, being spread upon a fibrous material, forms a filterbed which will remain intact on account of the rigid support behind the fibrous material, and the screen itself is also supported from the interior by a certain arrangement of cross pieces or braces within the filter-frame.

I11 my present invention, A is the filterframe, which is made of any suitable material; but I prefer to make it of sufficientlyheavy sheet metal, and 13 3 are diagonallyarranged bracing-pieces extending from the corners of the exterior frame toward the center, perforated so as to allow a free circulation of water through all parts of the interior of the frame; These strips B are as wide as the depth of the filter from side to side, so that when the filtering sides are secured upon the sides of the frame A they will be supported by the edges of these bracing-strips.

The sides of my filter are formed of wirecloth, finelyperforated sheet metal, or in some cases a fine lattice-work of anysuitable material D, having the ends projecting and forming prongs D, as shown in Fig. 1, and upon this is spread the fibrous material E, which is designed to support the filter-bed F. This fibrous material I have preferably shown made of asbestus, as being the most durable, and its edges are passed over and partially held by the prongs of the lattice-work D, as shown in Fig. 1, and the filter-bed comprises a coating of finely-pulverized charcoal, which is applied by mixing it with water, so as to form a paste, which is afterward brushed upon and into the fibers of the cloth until a sufficient thickness has been applied. The water percolates through this filter-bed of charcoal paste and through the cloth and the wire screen into the interior of the chamber formed by these filtering sides and the supporting-frame A.

In order to secure the fibrous material to the wire or other screen or support, I have shown metal plates folded so as to fit over the edges of the screen, and the fibrous material or cloth is made sufficiently larger than the screen so that it folds over the ends and sides of the screen. These folded metal strips G are then pressed on over these edges and are afterward soldered or otherwise secured to gether at their meeting angles, and suit-ably braced by re-euforcing corner-pieces, which also prevent leakage at the angles, thus securing the fibrous material so that it forms a smooth and unyielding surface, upon the exteriorof which the filter-bed is applied, as pre' viously described. The folded plates which form the surrounding edges of the filtering sides are then soldered or otherwise hermetically secured upon the edges of the frame A,

and the diagonal bracing-pieces B support the central portions of the screen-surface upon which the cloth is strctchechthus preventing the screen from being bent inwayd by the pressure of water upon it, and the screen in turn prevents any inward sagging of the fibrous cloth. This is important, because if any sagging of this kind should take place the paste or filter-bed which is applied to the cloth will fall off, and thus impair the efficiency of the filter. By this construction I am enabled to entirely dispense with any outer covering or support for the filter medium, and it enables me at all times to easily cleanse the filtering-surface or replace the filter bed upon it.

Another importantfeature in my invention is the manner of securing the edges of the cloth or fibrous material so as to form a wa- 2o ter-tight joint around these edges and prevent any leakage of unfiltered water through this joint.

This filter-frame is contained within an outer casing or chamber H, and the filterframe has a tubular stay I, passing through its top, bottom, and also through the interior bracing-strips B, to which it is secured. It is also secured to the top and bottom of the filter-frame by flanges or collars, so that when 3 the filter is lifted by the tube I it is perfectly rigid and the bottom cannot sag. The extension of the tube I at the bottom has a suitably-formed ground-rubber or other watertight joint I, which connects with the pipe deliveringintothereservoir-chamberbeneath,

which isa-dapted to contain the filtered water. This pipe I is perforated inside of the case A, so that the filtered water which has flowed into this case through the filtering 40 sides may pass through these perforations and thence down through the pipe into the reservoir or discharge-pipe, as the case may be.

In order to prevent the filterframe from rising up within the exterior case, I have shown two parallel-strips J, fixed across the upper part of the exterior case, and between these the upper end of the tubular stay passes. A nut or screw K is fixed to turn upon the threaded portion at the upper end of the tube I, and after the filter-frame is in place and the joint I properly connected at the bottom this nut is turned up against the cross strips or pieces J, and thus holds the frame in place, preventing it from rising. The filter-frame is easily removed by loosening the nut K and disengaging the pipe I from the joint at the bottom. The upper end of this tube serves to admit air into the interior of the filterframe by means of holes L, made in the tube or adjusting-collar just beneath the upper side of the filter-frame, and as the water passes down into the reservoirbenea'th through the holes which are made in the lower part or near the bottom of the filter-frame it will be manifest that the air will be caused to circulate through this tube, and will sufficiently aerate the water which has been filtered.

I prefer to construct the unfiltered water reservoir or exterior easing, into which the filter-frame is introduced, of iron, and the reservoir forcontain ing the filtered waterI preferably makeof tinned copper; but as this has not a great amount of rigidity to resist internal pressure I have shown a truss or bracing of steel or, iron plates M, covered with tinned copper, made of sufficient thickness to keep the top and sides of the reservoir in their proper position and to resist any pressure which may be brought upon the com paratively soft metal of the reservoirand which it is not stiff enough to resist. By thus separating the casing which contains the unfiltered water from the reservoir of the filtered water and uniting them, as shown, any leakage in the former will pass down outside of the filtered-water reservoir and not contaminate its contents. I am also enabled to make the unfiltered water tank of galvanized iron, which is inexpensive, and the filteredwater reservoir only need be made of the more expensive tinned copper.

By means of the truss plates or supports for the ground joints I prevent the reservoir from sagging or changing shape, and thus insure a perfect joint where the pipe I delivers water from the filter to the reservoir, and prevent leakage without a resort to screw or other connections which are more difficultto uncouple.

The water may be admitted into the case which contains the filter-frame either from the top or the bottom. In either case it is desirable to prevent the water from flowing in in such a manner as to create currents within the chamber, and thus disturb the filter-bed and wash it off. WVhen the wateris admitted from the top, it may be done by means of a cock N, having the ordinary float or ball 0 connected with the lever-arm, so as to cutoff the supply by closing the cock when a sufficient amount. of waterhas been admitted into the exterior chamber. From the mouth of the cock I have shown directing-plates P, which are so arranged as to receive the water as it flows from the cock, and to deliver it against the sides of the chamber so that it will fiow down gently and easily and without any splash, which would disturb the water and make it liable to wash off the filter-bed.

In order to render the sides of' the sheetmetal vessel which contains the filter-frame sufficiently stiff to support the ball-cock N and to allow the movement of the cock by the rise and fall of the float without twisting or bending the side of the chamber, I have shown the re-enforcing plate Rsoldered or otherwise secured to the side of the Vessel under the ball-cock, thus imparting as much rigidity to the vessel at this point as will enable it to withstand the twisting pressure caused by the rising and falling of the ball, and as the side is thus prevented from yielding it will insure the cock acting perfectly so as to cut off the supply of water and prevent a con- IIO stant leaking, which might otherwise occur, or the necessity for making the vessel of very much heavier material.

For the purpose of lessening the cost of manufacture, to facilitate the cleansing of the filter and renewal of the filter-bed, to increase the capacity, and to detect and locate leakages, I have shown in Figs. 3 and4 an exterior case adapted to contain two or more filteringframes, each constructed as previously described and adapted to fit within the exterior case side by side, where they are held in place by the tubular stays I, and each of the pipes through which the filtered water escapes at the bottom is fitted into a grou nd-j oint, which joint is supported by therigid iron or metal bar fitted into the sides and top of the reservoirtank and having a direct bearing thereon, and this gives great stability and rigidity to these joints, insures their remaining tight, and prevents leakage of unfiltered water from the case holding the same into the filteredwater reservoir.

In order to inspect the interior of the reservoir at any time when the water has been drawn off, I have shown a large screw cap or cover S, fitted into one end of the reservoir, preferably by screwing into a ring or flange which is fixed into the end of the reservoir. hen this is removed, the interior of the reservoir is easily reached and inspected, and if it has been discovered that the water from the reservoir is in any way contaminated I am enabled by removing this cover to detect any leakage from the tanks above, and by collecting a portion of the water delivered from each one in a glass I can at once determine which of the filters in the case above is delivering impure water. This may then be removed after discharging the water from the tank and the error rectified without disturbing any of the other filtering-frames.

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

1. Afilter consisting of asbestus cloth or other fibrous material, an exterior coating of filtering medium spread upon the cloth, and an interior rigid supporting-screen over which the fibrous material is stretched and by which it is prevented from sagging, said inner supporting-screen having projecting prongs over which the edges of the fibrous material are passed, whereby said material is secured, substantially as herein described.

2. In a filter, the foraminousplate or screen forming an interior rigid support for the filter-bed, a filter-bed composed of asbestus cloth or other fibrous material stretched over the exterior of the screen and having the edges projecting and folded over the edges of the screen, and folded metal plates adapted to clasp the edges of the cloth and the screen, said plates being soldered or secured So as to retain the screen and cloth and form a tight joint between the edges thereof, substantially as herein described.

3. A filter consisting of asbestus cloth or other fibrous material and an exterior coating of filtering medium in the form of paste spread upon the cloth, a rigid interior screen forming a back or support for the filter-bed, over the edges of which the cloth is folded, clan'iping strips fitting over the folded edges of the cloth and soldered or secured so as to retain it stretched over the screen, and supplemental corner pieces or plates fitted upon the angles of the filter-frame, substantially as herein described.

4. In a filter, the exterior frame having the filtering sides, the supporting-screens, and the diagonal plates upon which the screens rest, in combination with the tubular stay extending vertically through the filterframe and diagonal plates and having the adjustingcollars, whereby the stay is connected with both top and bottom of the frame and the central plates, so that the filter-frame may be lifted without twisting it out of shape, substantially as herein described.

5. In a filter, the filter-frame having the diagonal and perforated bracing-plates, the sides formed of screens supported upon the edges of the interior plates and hermetically secured to the edges of the frame, a fibrous filter-bed stretched over said screen, having its edges secured thereto, and a coating of filtering material applied to the exterior of the fibrous cloth in the form of a paste, in combination with an exterior casing for containing unfiltered water within which the filter-frame is submerged, and a'tubularstay extending through the filter-frame from top to bottom, having perforations in the lower part within the filter-frame, through which water may flow from the interior of the filterframe into the tube, a ground or rubber joint exterior to the lower part of the filter-frame,-

through which the filtered water passes out, and a transverse brace fixed across the upper part of the casing and having a locking device which engages the upper end of the tubular stay, whereby the filter-frame is prevented from rising and the joint at the lower end is kept tight, substantially as herein described.

6. A filter consisting of an exterior casing, one or more filter-frames having the filtering sides, interior screen-supports for said sides, and the plates upon which the screens are supported, a tubular stay extending through each of the filters, having a ground or rubber joint at the lower end, by which connection is made with the reservoir or receiver of the filtered water, openings in said tube near the bottom and interior of the filter frame, through which water escapes therefrom into the tube, and openings in the upper part within the filter-frame, through which air may be admitted from the upper end of the tube to aerate the filtered water, a transverse brace fixed in the upper part of the exterior casing, and adjusting nuts or collars fitted upon the tubular stay, so as to engage the brace and hold the filtenframes in place within the easing, substantially as herein described.

7. A filter consisting of an exterior casing, one or more filter-frames having the filtering 5 sides through which the Water passes from the exterior casing to the interior of the filter-frames, and a pipe or passage through which the Water escapes from the interior of said filter-frames, in combination Witha res- IO ervoir into which said pipes deliver the filtered water, a ground or rubber joint between the unfiltered and filtered water reservoirs, and a strengthening stay or support within the filtered-Water reservoir, upon which the ground-joint is fixed and supported, substan- I5 tially as herein described. 7

In witness whereof I have hereunto set my hand.

EDWARD M. KNIGHT. Witnesses:

S. H. NOURSE, H. 0. LEE.