US2155943A - Intermittent air actuated acid feeder - Google Patents

Description

l April 25, 1939.

A. E. KITTREDGE ET AL INTERMITTENT AIR ACTUATED ACID FEEDER Filed Jan. 4, 1938 2 Sheets-Sheet l lNv NToRs W ,ioRNEY Z April 25, 1939; A E4 KlTTREDGE ET AL 2,155,943

INTERMITTENT AIR ACTUATED ACID FEEDER Filed Jan. 4, 1938 2 Sheets-Sheet 2 WMM www,

ATTORNEY Patented Apr. 25, 1939 UNITED STATES INTERMITTENT AIR. AotlnA'rED! ACIDy FEEDER.

Arthur E. Kittredge, Audubom N. J., and Victor A. Roblin, Glenside, Pa., assignors to Cochrane Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application January 4, 1938., Serial No. 183,318

3 Claims.

The general object of the present invention is to provide improved means for discharging .a corrosive liquid, such as an acid, from a storage chamber or receptacle. A more specific object of r the invention is to provide improved means for discharging acid or other corrosive liquid from a supply chamber or reservoir, in doses or charges, each of which constitute a small fraction only of the .amount of the corrosive liquid which can be held in the storage reservoir.

Other specific objects of the invention are to provide corrosive liquid feeding means, including a feed chamber so connected with the storage chamber and with discharge piping, that the corrosive liquid is caused to alternately pass into the feed chamber from the storage chamber, and from the feed chamber into the discharge piping, by increasing and reducing the air pressure acting on the liquid in the feed chamber, and

20?- to provide feeding means-which includes no iioat or movablermechanism part in contact with the corrosive liquid, and has no valve or packing normally in contact with the corrosive liquid.

While not restricted to such use, the Vpresent invention Was primarily devised, and is especially adapted, for use in neutralizingr or eliminating excessive alkalinity in waterl given such alkalinity by a purifying treatment. For such use, it is necessary to closely proportion the amounts of added acid and of water to which the .acid is added, and to accommodate a Wide. range of variation in the daily or hourly rate of water treatment. In such case, the air used in the acid feeding operation may be furnished by a motor driven blower which is started into operation to initiate each acid feeding operation, .and which continues in operation for a period which should be long enough, at least, for the completion of the feeding operation. In so far as it directly concerns the operation of the feeding apparatus, it is immaterial whether the blower stops immediately at the end of each feeding operation, or continues in operation for an indefinite period thereafter, provided only that the operation is interrupted soon Ienough 5 feeding operation, and including a timing mechanism for stepping the motor after a period of operation, no-t shorter than the. maximum time period required for an acid feeding operation.

The various features of novelty which characterize the. present invention are. pointed out with particulaiity in the claims annexed to and forming a part of this invention. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be-had to the accompanying drawings and descriptive matter in which we have illustratedv a preferred embodiment of the present invention.

Of the drawings:

Fig. 1 is a sectional elevation of a preferred embodiment of the present invention;

Fig. 2 is an elevation taken at right angles to Fig. 1, with parts broken .away and in section;

Fig. 3 is a partial plan view, in section on the line 3-3 of Fig. 2;

Fig. 4 is a diagrammatic elevation, illustrating cepft that Fig. 5 shows liquid levels existing in an intermediate stage, and Fig. 6 shows liquid levels existing at the end of a feeding operation. y

The general nature and mode of operation of our corrosive liquid feeding apparatus, is illustrated in the diagrammatic Figs. 4, 5, and 6. The apparatus shown in those figures comprises a corrosive liquid storage chamber, a, a measuring, or calibrated feed chamber cylinder c,

and a U conduit connection between the chamt ber a and cylinder c, comprising vertical limbs b and b' connected .at their lower ends. limb b is formed by a pipe sectionV extending downward from an outlet a in the bottom wall of the chamber a. pipe section having its upper end opening into the'chamber c. As shown, the level o-f the upper end of the pipe section b is slightly below the level of the upper end of the feed chamber cyl inder c and slightly above the upper end of the pipe section b. The connected lower ends of the pipe sections b and b' are below the minimum water level in the feed chamber. An uprising discharge pipe d is connected to the lower end of the cylinder c. The pipe d leads upward to a discharge outlet including a weir e, located at a level above the highest liquid level maintained in the chamber a. Liquid moving upward through the pipe d, flows over the Weir-"e into the pipe e' through which the liquid fed is'. f

passed to the place at whichit is used. As shown',

Vthe pipe d includes an upper vent portion d',

extending upward above the weir e, and open at its upper end to the atmosphere.

The space within the chamber c, above the liquid level therein, is in communication with the atmosphere through a vent connection g. A compressed air supply pipe f hasa downwardlyextending lower end portion which opens into the cylinder c, through the top wall ofthe lat- TheY The limb b' is formed by a ter. The pipe f is in communication with the air space in the chamber` a through a restricted orlce f. A portion f2 of the pipe F between the orifice f' and the feed tank, is in the form of an inverted U, or gooseneck, so that corrosive liquid slugs, or condensate drops, in the pipe f, will drain either into the cylinder c, or into the supply reservoir a.

From the dose or charge measuring viewpoint, the cylinder c may be regarded as constituting the feed chamber, of the apparatus shown in Figs. 4, 5, and 6, but from an operative viewpoint, the feed chamber includes not only the cylinder c, but also the portion of the pipe f below the level of the liquid in the reservoir chamber a. With the air pressure in the pipe f equal to the pressure of the atmosphere, the liquid levels will be the same in the chamber a, in` the delivery pipe d, and in the feed chamber, as shown in Fig. 4. The initial effect of a suitable increase in the pressure in the pipe f, is a backlow of liquid from the chamber c into the chamber a,through the U connection pipes b and b, which continuesl until the liquid level in the chamber c is at the top'of the pipe b; Such return of liquid to the chamber a results in some actual increase in the height of the liquid level therein, but that increase is too small to be of significance, when the horizontal cross section of the chamber a is very much greater than that of `the cylinder c, as is normal. While liquid is thus being returned from cylinder'to chamber a, there is no significant increase in the hydrostatic pressure in the lower portion of the cylinder c, or height of liquid level in the discharge pipe d, though theoretically there is some such increase, because the head loss due to the flow through the pipes b and b.

As the pressure in the pipe is further increased, the liquid level in the pipe b is lowered, and the liquid level in the pipe d is correspondingly raised until it reaches the level of the Weir e, as shown' in Fig. 5. As the pressure in the pipe ,f continues to increase, liquid is forced out oi the feed chamber through the pipe d and over the weir e into the delivery piping e'. At the end of each normal feeding operation, the liquid Vlevels in the chamber c and pipe b will be as shown in Fig. 6, and the air pressure in the pipe f2 will correspond to the liquid head h4.

For the attainment of the .operative results and advantages contemplated, certain level relations are required in the apparatus shown in Figs, 4, 5, and 6. For one thing, the elevation, h', of the weir e, above the level of the connection of the lower end of the pipe d to the feed chamber c must exceed the elevation, h2, of the maximum working liquid level in the tank a above the level of the connected lower ends of the portions b and b' of the U-tube feed connection. The elevation, h3, of the outlet a of the chamber a, above the connected ends of the pipe portions b and b' should exceed the elevation, h4, of the level of the weir e, above the minimum level, c', to which the liquid in thecylinder c is-depressed by the air pressure in thepipe f. If at the end of 'each feeding operation, the same liquid level c exists,

due to the effect of variations in level in the chamber a, on the amount of liquid in the pipe d lat the beginning of the feeding operation.

With the levels related as shown and described, so that the distance h3 is greater than the distance h4, the lower portion of the U conduit connection between the cylinder c and chamber a will be liquid sealed and air will not blow into the chamber a, through the tubes b' and b, unless the air pressure in the pipe f exceeds the predetermined normal maximum feeding pressure. With the described level relation in which the .distance h exceeds the distance h2, an abnormal increase in the air pressure in the pipe ,f will result in the air blowing out of the cylinder c, not through the discharge pipe d, but through the pipes b and bf into the chamber a, where it can do little damage.

The commercial embodiment of the invention shown in Figs. l, 2, and 3, comprises parts A, A', B, B', C, D, D', E, E', F, F', F2, and G, respectively similar or more or less analogous to the parts a, a', b, b", c, d, d', e, e', f, f', f2, and g, of Figs. 4, 5, and 6. As shown, the chamber A is a compartment partitioned olf in the upper portion of a vertical tankdike structure A10. The feed chamber cylinder C is coaxial with the chamber A, and exten-ds through its bottom wall outlet opening A. The cylinder C is closed at its lower end, and has its upper end separated b-y an interposed head C2 from an aligned tubular part C3, depending from the top wall of the chamber A. The U conduit connection betweenthe chamber A and cylinder C com-prises portions B and B. The portion B is formed by a tube mounted within the Vcylinder C, and opening at its lower end through the bottom wall of that chamber, and opening at its upper end to the cylinder C at a level slightly below the bottom of the chamber A. The passage portion B comprises the annular space between the cylinder C and a surrounding tubular shell B3. The latter has a closed lower end, and has its upper end open andY secured to the bottom wall of the chamber A in register with the outlet opening A in that wall. The lower end of the part B3 is spaced beneath the lower end of the cylinder C to provide suitable communication between the portions B and B' of the U conduit connection between the chamber A and `cylinder C.

The lower end of the air pressure pipe F is anchored in the head A2 and communicates through a passage in the latter with the cylinder C. The gooseneckportion F2 of the pipe F is above the top Wall of the chamber A, and the port F is formed in a portion A2 of the top wall of the Vtank A to which separate adjacent p'ortions of the pipe F are connected. The body of the cylinder C', its ends, the tubular part C3 and the various pipes which are Vexposed to contact with the liquid may be made of suitable corrosive resistant material such as lead, and the shell B3 and the chamber A may be lead lined. As shown,

a dome A3 mounted on the top wall of the chainiber A, encloses and provides protection for adjacent portions cf the piping. The pipe G extends vertically upward through the bottom wall ofthe chamber A, to the maximum desired liquid level in that chamber, and is adaptedto serve as level limiting overiiow connection to the cham# ber A, as Well as to serve as an air vent or breather passage in normal operation.

In the apparatus shown in Figs. 1, 2, and 3, the air under pressure in the pipe F and chamber C, is supplied by a blower I driven by an electric motor J. The outlet pipe I of the blower I connects to the inlet of a liquid eliminating separator K, shown as provided with a valved drain K. The air outlet of the latter is connected through a needle valve L, check valve L', pressure reducing valve M, and pressure regulator O, to the pipe F. The pressure chamber in the regulator O, is connected by a pipe P to a pressure gauge Q, the pointer position of which indicates the pressure in the pipe F' and thereby the operative stage or c-ondition of the apparatus.

The parts I, J, K, L, L', M, O, and Q may all be of standard commercial types and all those parts except the gauge Q are advantageously mounted within the shell A10.

'Ihe separator K serves the double purpose of a collector for compressor oil and an air chamber to smooth out or eliminate pressure surges in the air flowing away from the separator, when the air compressor is started into operation. The needle valve L between the separator K and reducing valve M definitely restricts the iiow of air and requires thepressure within the separator K to be appreciably above atmospheric pressure when the air pump is delivering sufficient air to permit the regulator O to perform its regulating function. The flow of air past the needle valve thus begins gradually, notwithstanding the quick starting of the compressor into full speed operation when connected to the line. In passing through the intermediate operating stage shown in Fig. 5, the air pressure in the feed chamber needs to be but little above atmospheric pressure and appreciably below its final maximum value of the apparatus in the condition shown in Fig. 6. The rate at which oil will collect in the separator K is slow, and the oil may be withdrawn from time to time by manual adjustment of a cock in the drum K.

In Fig. l, J represents a control mechanism for starting and stopping the motor J. As will be apparent, the motor may be started and stopped manually to effect the feeding operations above described, but for the use of the apparatus for some purposes, an automatic control of the starting and the stopping of the motor is advantageous. One use of the apparatus shown primarily contemplated is for the addition of sulphuric acid doses to boiler feed water which has passed through a zeolite filter (or softener) to avoid boiler steel embrittlement because of unsuitable sulphate to carbonate ratio in the boiler water and the contamination of the steam formed by CO2, which the high alkalinity of the water would otherwise produce. For such use, the water treating rate may be such as to require an acid feeding operation every three or four minutes and that the compressor should operate for a minute or so at each feeding operation. In such use, a full charge of acid in the tank A may be proportioned to hold suicient acid for a twelve hour operating period.

While in accordance with the provisions of the statutes, we have illustrated and described the best form of embodiment of our invention now known to us, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of our invention as set forth in the appended claims and that in some cases certain features of our invention may be used to advantage without a corresponding use of other features.

Having now described our invention, what We claim as new and desire to secure by Letters Patent, is:

1. Liquid feeding apparatus comprising in combination, a liquid storage chamber having a lower liquid outlet, a feed chamber extending downward below the level of said outlet, a U conduit connection between said outlet and feed chamber comprising two limbs connected at their lower ends one of said limbs being connected at its upper end to said outlet and the upper end of the other limb opening to said feed chamber adjacent the upper end of the latter, a discharge pipe having its inlet -end connected to the feed chamber at a level substantially below the level of said outlet and having an outlet located at a level above the maximum liquid level in said storage chamber, and means for subjecting the liquid in said feed chamber to an air pressure varying between that required to depress the liquid level in the feed chamber substantially below the upper end of said second limb and that at which the liquid levels in the reservoir and feed chamber equalize.

2. Liquid feeding apparatus comprising in combination, a liquid storage chamber having a lower liquid outlet, a feed chamber extending downward below the level of said outlet, a U conduit connection between said outlet and feed chamber comprising two limbs connected at their lower ends, one of said limbs being connected at its upper end to said outlet and the upper end of the other limb opening to said feed chamber adjacent the upper end of the latter, a discharge pipe having its inlet end connected to the feed chamber at a level substantially below the level of said outlet and having an outlet located at a level above the maximum liquid level in said storage chamber and means for subjecting the liquid in said feed chamber to an air pressure varying between that required to depress the liquid level in the feed chamber substantially below the upper end 0f said second limb and that at which the liquid levels in the reservoir and feed chamber will equalize, the difference in levels between the discharge pipe inlet and outlet being greater than the difference between the maximum water level in the storage chamber and the level of the connected lower ends of said limbs. Y

3. Liquid feeding apparatus comprising in cornbination, a liquid storage chamber having a lower liquid outlet, a feed chamber extending downward below the level of said outlet, a U conduit connection between said outlet and feed chamber comprising two limbs connected at their lower ends, one of said limbs being connected at its upper end to said outlet and the upper end of the other limb opening to said feed chamber adjacent the upper end of the latter, a discharge pipe having its inlet end connected to the feed chamber at a level substantially below the level of said outlet and having an outlet located at a level above the maximum liquid level in said storage chamber and means for passing air into said feed chamber to establish a predetermined air pressure therein and thereby depress the liquid level in the feed chamber below the upper end of said second limb, a distance less than that required to make the distance between the liquid level in the feed chamber and the discharge pipe outlet level, as great as the difference in levels between the storage chamber outlet and the connected lower ends of said two limbs.

ARTHUR E. KITTRiEDGE. VICTOR A. ROBLIN.

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