US426139A - Apparatus foe distilling and concentrating liquids - Google Patents

Description

2 Sheets-Sheet 1.

(No Model.)

0. 0.. PEGK. APPARATUS FOR DISTILLING AND GONGENTRATING LIQUIDS.

Patented A pr. 22, 1890. 1

I ll H 2 Sheets-Sheet 2.

(No Model.)

0. 0. PEOK.

APPARATUS FOR DISTILLING AND OONGENTRATING LIQUIDS.

No. 426,139. Patented Apr. 22, 1890.

WWW/S366 V Inventor W 6. yep/Q Unrrnn Srarns PATENT OFFICE.

OASSIUS C. PEGK, OF NE\V YORK, N. Y.

APPARATUS FOR DiSTlLLING AND CON CENTRATING LIQUIDS.

SPECIFICATION forming part of Letters Patent No. 426,139, dated April 22, 1890.

Application filed April 6, 1889. Serial No. 306,237. (No model.)

To an whont it may concern.-

Be it known that I, CASSIUS G. PECK, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new an d useful Improvements in Apparatus for Distilling and Concentrating Liquids, of which the following is a specification.

My invention relates to those processes of distilling and evaporatii'ig in which vacuumpans are employed for removing vapor from the liquid being treated, and more especially to the class of operations in which several sets of apparatus are so connected as to be supplied consecutively from the first apparatus with the heat necessary for effecting evaporation rapidly.

It consists in substituting for the ordinary vacuum-pan an apparatus consisting of a metal, wooden, or masonry tank provided with a heating-coil, in which tank avacuum-eylinder is placed vertically, and in connecting a number of such tanks in such manner that the heat primarily imparted to the liquid in the first tank shall be carried through the liquid of each tank constituting the series; also, in connection with the discharge-pipe of the heating-coil aforesaid, of means for automatically discharging the liquid of condensation and at the same time heating the necessary supply of feed-liquid In the drawings, Figure 1 shows in vertical central section the general arrangement of a series of evaporating reservoirs or tanks, together with the boiler used both for preliminary heating of the feed-liquid for the tanks and for furnishing steam to the heating-coil in the first evaporating-tank and for driving the air and liquid pumps, and also the well wherein the liquid of condensation from the several tanks is collected. Fig. 2 is a central vertical section of the trap used for discharging condensed steam from the coil in the first tank. Fig. 3 is an enlarged cross-section of the trap through plane of line a; a, Fig. 2. Fig. i is a plan or top view of two evaporatingtanks of a series to show the arrangement of the combined heater and condenser coils, also showing the cylinders of the conveyors which remove deposits from the tanks. Fig. 5 is a vertical sectional view of one of the evapo rating-tanks, taken through plane of line a: 0:, Fig. 4.

ducts of combustion proceeding from furnacc F, which products pass through tubes I) in the boiler and thence upward to and along the bottom of the evaporating-panE to the discharge-flue c. The shell of the boiler is broken away at the upper portion to show the tubes referred to and also the level of liquid in the boiler. Steam for heating the coil a in tank A is conveyed through pipes Z) If, and for air and liquid pumps and any other requirements through branch pipe 1). Suitable valves b b in the respective pipes control the supply of steam. \Vhen the liquid to be evaporated or distilled requires previous heating to remove air, which would otherwise collect too rapidly in the vacuum-cylinders C C C and condensercoils a a a of the tanks A A A and necessitate the constant use of an air pump or pumps of large size to secure its removal, or when it is found desirable to heat it for any other purpose, and the liquid is of such a nature that its vapor can be used for heating the coil a and for power, no additional boiler is required. The liquid is delivered by a pump or sufficient head through, pipe 7L into the reouperativc heater H, and passes out at the upper end of the heater through pipe h to boiler B. A check-Valve 7L prevents con stant reaction of the boiler-pressure on the pump or head of liquid. As the liquid becomes heated in boiler B it rises and finally passes out through pipe '7', which traverses heater H and extends to the common supplyrescrvoir R. The valve r controls the rapidity of delivery from boiler B, and is opened or closed correspondingly with valve h. As the heated liquid issuing from the boiler circulates downward in pipe r through heater I l, it gradually parts with the excess of caloric which it contains as compared with the feedliquid, which otherwise fills the heater, until it passes out at the lower end of the heater at nearly the temperature of the feed-liquid entering through pipe it. This feature is more particularly described in my patents, Nos. 329,072 and 829,073, dated October 27, 1885.

When the liquid leaves a deposit of solid matter in boiler B, its removal while the boiler is under pressure is provided for by a lockchamber formed by placing two valves 1) b in an extension of the lower end of the boiler.

The contents of the chamberb are discharged into a hopper-truck J by closing the upperv valve Z) and opening the lower valve 1).

If the liquid is of such a nature that it-cannot be used for heating and power, as described, a separate boiler is provided for the latter requirements.

The liquid to be evaporated or -distilled is conducted from reservoir R by pipe r and branch pipes r r to the bottoms of the heater-jackets K K K in well W, and from the upper ends of said jackets by pipes r r r to tanks A A A the supply to each tank be ing regulated by valves 4" 2' r.

The vacuum portion of the apparatus in each tank consistsof the cylinders O O G, the lower ends of which remain always submerged in the liquid to be evaporated. The height of the cylinders must be from thirty to forty feet for a liquid having the specific gravity of water, if it is intended to maintain a high vacuum, but may be correspondingly less in height as the degree of vacuum is lowered.

A partial vacuum is created in each of the cylinders G 0 O in commencing operations, by an air-pump, with which each of the cylinders and condensing-coils a a a is 0011- nected by pipe P, Fig. 1, and branch pipes 1? P (Also shown in Fig. 5.) After the apparatus is in full operation the vacuum is maintained without the use of the air-pump, except as it is required from time to time for removal of air which accumulates in the cylinders and condensers, derived from the liquid which is being evaporated. The air-pump may, however, be worked continuously, as is usual with vacuum apparatus A. separate ainpump may be provided for each cylinder; but in case of most liquids, especially if prepared by previous heating, air collects so slowly that a single pump may answer for more than one cylinder. The operation will, however, be more satisfactory if each cylinderhas its separate pump, so as to regulate the vacuum in each cylinder separately from every other cylinder.

When the apparatus is ready for operation, the liquid to be treated is introduced to each I of the tanks A A A through pipe r connecting with reservoir R, until the bases of the cylinders O O O are submerged,when the air-pumps connected with the cylinders and with the condensing-coils a a a may be started and operated until the desired amount of vacuum is produced in the cylinders and coils. The liquid contained in the tanks rises in the cylinders C O C in proportion to the degree of vacuum which has been produced therein, and more feed-liquid is supplied to the tanks or sufficient to make up for the quantity which has been forced upward into the cylinders by pressure of the exterior atmosphere and to insure that the bases of the cylinders shall always remain immersed in the liquid. Each tank is preferably made large enough to avoid overflow in case the degree of vacuum is suddenly and largely reduced in the cylinders, and the level of liq uid in the tanks is maintained at such a point as to allow of the cylinders being emptied without overflowing the tanks. As the liquid in tank A becomes heated, vapor passes off rapidly from its surface into cylinder C in proportion to the degree of vacuum, the temperature of the liquid, and the rate at which the vapor is condensed in coil a, into which it flows through pipe 0. In condensing, the liquid gives off its latent heat to the liquid in tank A, and as this liquid becomes heated the resulting vapor escapes from its surface in cylinder 0 and enters through pipe 0 the coil a in tank A where, in condensing, it heats the liquid in the tank, and the same cycle of evaporating, condensing, and heating of liquid goes on through the whole number of tanks which compose the series, and at the end of the series the vapor from the last cylinder is condensed in a tank provided with a coil, but containing no vacuum-cylinder. Each of the tanks has a cover Gr, Figs. 1 and 5, composed of two thicknesses of plank, between which is a layer of felt. The lower surface of the cover is protected by sheet metal. Any other suitable materials which are non-conductors of heat may be employed for constructing the cover, the use of the cover being principally to prevent escape of heat by radiation and evaporation from the liquid in the tank. The cover does not fit so closely as to entirely exclude air from the interior of the tank; or if the cover fits tightly on the side walls of the tank, then holes g, Figs. 1,4, and 5, are made through the cover for admission of air.

The liquid of condensation flows away from the coils a a a by pipes a a a as fast as it forms, and collects in well W, from which it is pumped or otherwise discharged in any convenient manner. Then it is desirable that the liquid of condensation formed in each of the coils shall not be mingled, each of the pipes a a a is made to discharge intoa separate receptacle. As the first coil a'is under pressure of steam from boiler 13, the discharge of water of condensation has to be effected in a different manner from that suitable for the vacuum-coils a a A head-plate k, Figs. 1, 2, and 3, is secured to the heater-jacket K, forming a support for the three rods and at the opposite or lower ends of the rods is a foot-plate 73, carrying an elastic seat 70 against which the tip a on discharge-pipe a impinges as the heating up of jacket K and pipe a causes them to lengthen by expansion. A guide-plate k upon pipe at keeps the rods in line with this pipe and jacket K. Screwnuts 011 the lower endsof the rods provide for bringing the seat k more or less closely to the tip a", and the adjustment is so made that the discharge of the liquid of condensatio';

shall be stopped by contact of the two parts when the temperature of the. liquid becomes ITO so much higher than that of the feed-liquid as it enters the jacket as to occasion an ap preciable and objectionable amount of loss of caloric. After stopping the discharge from pipe a, it and the jacket soon become so much cooler that contraction in their length occurs and the seat k and tip a separate until the pipe and jacket again become heated by discharge of the water of condensation. The discharge of the liquid of condensation from the vacuum-coils a a is effected by the Torricellian tubes a" G which connect with the lowest points in the coils at one end and dip into the liquid in the well V at the other end. The length of the vertical portions of these tubes is made at least equal to the height to which the liquid in the well would rise in the tubes with the degree of vacuum employed.

In flowing downward through pipes a a a, inclosed by jackets K K K the liquid of condensation gradually parts with its excess of heat as compared with the temperature of the feed-liquid which fills the jackets, and the latter liquid conveys it back to the respective tanks.

As the liquid of condensation and the feedliquid flow in opposite directions through the jacketed space and are about equalin amount, the former leaves the lower ends of the jackets at or about the temperature of the latter as it enters the jackets, and thus but little heat is conveyed away and wasted by the liquid of condensation.

In treating the large class of liquids in which precipitates are formed, as the degree of concentration increases with continued evaporation, the removal of solid matters as fast as they are deposited is elfected by means of screw conveyers I. m, Figs. 4 and 5. Each conveyer consists of a shaft Z, on which is secured a helix formed of plate metal or of woven wire Z, inclosed in a case or shell P. The shaft is driven by bevel-gear The lower end of the conveyer is fixed at that point in the tank where the greatest amount of deposit occursnamely, under the center of each vacuum-cylinder. The screw as it revolves takes up at its lower end the solid matter and carries it to the upper end of the shell, where it falls into a suitable receptacle. In the drawings, Figs. 4 and 5, is shown a second conveyer m, employed for removing solid substances discharged from series of tanks. This conveyer has a double bottom m, and between the two bottoms steam or any suitable hot fluid is circulated when it is desired to remove moisture from the material which is being handled. This heat of steam or hot liquid may be depended on for driving off moisture, or the process may be assisted by attaching a fan-blower to one end of the conveyer and forcing or drawing air through the case or shell. in opposite direction to the movement of solid material. The helix of this second conveyer is formed like that of the first conveyor, or it may consist of connected or unconnected arms fixed spirally around the shaft, depending upon the nature of the ma terial being handled.

I do not confine myself to the screw form of conveyor either in case of couveyer m or conveyer L, as buckets attached to chains carried around suitable driving-pulleys can be made to do almost equally well and in some cases even better than screws inclosed in shells.

The tanks A A A and vacuum-eylinders C C and all connecting-pipes are well insulated by covering with non-conducting materials. As the percentage of heat lost by ra diation is thus made small, and as that heat which is contained in the liquid of condensation is mostly returned to the tanks by the feed-liquid, it becomes possible to convey the caloric imparted to liquid in the first tank through a number of tanks constituting a series. As the number of tanks is increased, the amount of condensing-surface in each coil requires to be correspondingly increased in order to obtain the same amount of liquid of condensation in a given space of time. This is a feature of my invention which is applicable to all multiple-effect vacuum apparatus. In general I find that an increase of condensing or heating surface of twenty-five per cent. for each cil'ect gives economical and satisfactory results.

Although the apparatus described is de signed primarily to be used in series, it is equally well adapted for use as a single-effect apparatus in substitution for the ordinary vacuum-pan. Among the advantages over the common vacuum-pan are less first cost, accessibility for removal of deposits without stopping the process of evaporation, better opportunity for observing the condition of the liquid under treatment, convenience in cleaning the heating-surfaces, and the less diameter and greater strength which can be given to the cylinder for a given capacity.

The apparatus described is suitable for evaporating all kinds of liquids where ordinary vacuum-pans would be employed; but in removing moisture from semi-solid substances the process cannot be carried so far in the tanks A A A as in vacuum-pans, for the reason that the material treated must contain sufficient liquid. to form a seal at the bases of the cylinders O O C to prevent access of air to the interiors of the cylinders; but by withdrawing from the tanks, by means of conveyers L L, solid matter as fast as deposited and finishing the drying process in a secondary conveyor m the apparatus is made not only the equivalent of vacuum-pans, but greatly superior to them.

The vacuum-cylinders C C C are made of suitable diameter for the amount of liquid to be evaporated in each, and the height is determined. by the degree of vacuum to be maintained. By the arrangement of valves and pipes shown. in Ft i 1 and 4 any one or more cylinders of a series can be cut off or disconnected from the remaining cylinders of a series without stopping the process of evaporation in those cylinders which remain connected.

I do not confine myself to the form of condenser-coils made up of pipes as shown, nor to any particular shape of tank, as these may be put in a variety of shapes having about the same effect. The most important point in connection with the condensing-surface is that it shall be sufficient in extent to condense the required weight of vapor at the difference in temperature between the liquid in the tank in which it is placed and that in the tank which precedes it, and that which is most essential in the tank is that it shall not have an airtight cover, and that it shall be sufficiently large to contain the vacuum-cylinder, the combined heating and condensing coil, and the necessary amount of liquid.

The apparatus described is especially suited for carrying on evaporation on a large scale, as in concentrating brine in the manufacture of common salt, and cane and beet juice in makingsugar, also in the distillation of petroleum, alcohol,&c., on account of the economy of fuel secured by repeated use of the heat employed to effect the first distillation. As the general description given is applicable for most liquids which require to be evaporated, it is not deemed necessary to single out any particular one and trace the operation in connection therewith.

The increased amount of heating or condensing surface required in each succeeding tank of a series is not shown in planin the drawings; but tank A is shown broken in two in Fig. 4, and the dotted or broken lines g 9 Fig. 5, indicate, respectively, the lengths of the tanks A and A in order to give room for the amount of heating-surface required in each.

An application for Letters Patent covering the process to the carrying out of which the before-described apparatus is applicable is filed on even date with the present application, Serial No. 306,239.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a vacuum apparatus, the combination, substantially as and for the purpose set forth, of a tank open to the atmosphere for containing the liquid to be evaporated, a vacuum-chamber opening at its lower end into said tank and sealed by the liquid therein, and a heater arranged to impart heat to the liquid in the tank to effect its evaporation within the said vacuum-chamber.

2. The combination, substantially as set forth, of a series of separate evaporating apparatus, each consisting of a tank open to the atmosphere for containing the liquid to be evaporated, a vacuum-chamber opening at its lower end into said tank and sealed by the liquid therein, and a heater arranged to impart heat to the liquid in the tank to effect its evaporation within the vacu um-chamber, the upper portion of the vacuum-chamber in one tank being connected wit-h the combined condensing and heating coil in the next succeeding tank or member of the series, for the purpose described.

3. In a Vacuum apparatus, the combina tion, substantially as and for the purpose set forth, of a tank open to the atmosphere for containing the liquid to be evaporated, a vac-' uum-chamber opening at its lower end into said tank and sealed by the liquid therein, a heater arranged to impart heat to the liquid in the tank to effect its evaporation within the said vacuum-chamber, a conveyer for removing solid matters from the tank or tanks, and a second conveyer formed with a steamchamber for heating the said its contents.

at. In vacuum apparatus arranged in series for multiple effect, substantially as described, the tanks A A A sufficiently open at the top to receive atmospheric pressure, a vacuumcylinder arranged in each tank and supplied therefrom, and a condenser-coil in each tank, excepting the first, connected with the upper portion of the vacuum-cylinder in the next preceding tank of the series, each condensercoil having a greater surface than the next preceding one, substantially as described.

CASSIUS O. PEOK. \Vitnesses:

N. S. WELLs, WM. E. MILLER.

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