US2394698A - Evaporator - Google Patents

Description

Feb. 12, 1946.

o. J. KuENHoLD EVAPORATOR4 3 Sheets-Sheet 1 5 lNvENTR. BY Orro JI KuENHoLD, SR.

Original Filed OG'(H 6, 1958 ATTORNEYS.

Feb. 12,1946.

o. J. KUENHLD, SR

EVAPORATOR Original Filed Oct. 6, 1938 3 Sheets-Sheet 2 INVENTOR. Orro J2 KUENHOLD, Se.

ATTORNEYS.

Feb. 12, 1946.

O. J. KUENHOLD, SR

EvAPoRAToR 3 Sheets-Sheet 3 Original Filed Oct. 6, 1938 INVENTOR. Orro J.' KuENHoLQR.

BY @www4 ATTORNEY Patented Feb. 12, 1946 UN IT ED STAT E S PAT 0F Fl C Ev EvAioRA'roR Otto J. Kuenhol'd, Sr., Shaker'Heights,: Ohio, assgnor to Monmouth Productsompany, Cleveland, Ohio', a corporation of (Jho d Continuation of application Serial No'. 340,827, June 1940, which is a divis-ol'i'ff- Serial No.

233,631, October 6, 1938.A

August 7, 1942, seal No'. 453,990

11 claims'.

The present invention relatesy to an evaporatin'g device particularly adapted for use in the heating, Ventilating and air conditioning art, and is of the type wherein evaporation of water and its entrainment in a passing air stream is obtained by means of porous, ceramic plates dismy United states Letters Patent No. 2,166,414,-

granted July 18, 1939, for Humidifying system. The present application is a continuation of my divisional application Serial Number 3&'O,82'7,i le'd June 15, 1940, said divisional application being a division of my application Serial Number 233,631, filed October 6', 1938, and issued Apri-l 1v,- 1941,` as United States letters Patent No. 2,236,538.

The general object and nature of my present invention vis to provide an evaporator of the type indicated having a much greater evaporation rate capacity and increased life or period of service. Additional objects and advantages of the invention shall become apparent as the follov'vir'igV description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims. v The annexed drawings and the' following description setforth in detail certair'iI mechanism embodying the invention, such disclosed means constituting, however, but one of various Inechanical forms in which the principle of the invention may be used.

In said annexed drawingshand endg elevation f the: water Dan; Fig. 11 is a cross-"setional view taken substantially along the line l'l-r-'ill {if} 7; Fig'. 12y is a longitudinal sectional view' showing one' means of varying the Fig. 1 is a view illustrating an evaporating' plate of Fig. 1; Fig. 3 is a partially diagrammatic figure ofan evaporator plate and water pan and is for the purpose of aiding in the explanation of the principle of my invention; Fig. 4 is a top plan view of onefhalf of one of the evaporating plates having the improved construction; Fig. 5 is a longitudinal sectional view of the water pan and 'supporting' rack witli'one of the evapo'rating plates shown in positionj Fig. 6 is a top plan view of the evaporator embodying the principle of my invention; Fig. 7 is a side elevational view thereof; Fig. 8 is a cross-sectional view taken substantially along the line 8.-'8 of Fig. 7i Fig. 9 is an end elevational viewof the cover plate and water `feed apparatus for the evaporator; Fig. 1U is a right height oi the evaper'eting plates with respect to the Wafer level;- rid' Fig. lf3 is a longitudinal sectional view'shovving an alternative means of vary'- ing the height of the' evaporatingv plates with respeol" t0 the Watrl'evel.

Now referring to Figs. 1 and 2, it will be seen that the' porous ceramic' evaporating plate I shownthereii is in the form of a rectangle with a central downwardly extending tongue 2 c'ontacting withtl'e water in the Water pan or reservoirl 3. Projections 4' are provided in the bottoni f the' for' engaging withV the tongue 2 and notches 5 are vided in the upper edges of., the pan 3 for engaging with the body portion of .the plate l. yThe above illustrated and de"- scribed onst'ruc'tion is further set uforth and claimed in; my aforesaid Patent No.y 2,166,414. K

Porous, ceramic evaporating plates operate generally upon the principle' of absorbing water from the W'atby capillary action, presenting4 exposedvwet or' moistend surfaces for contact with a passing air streairi.l

New referring to Fig. 3, there is shown therein an evaporating plate consisting generally of the two half portions and B. A series of dotted line curves a to h inclusive represent the upper limits of Vth wet vor moistened area of the Plate at the following timeintervals' after the d lY Plate has been inserted in the Water pan with the level maintained at the line marked WL, viz.:

Upper limit of water penetrationV These curves a to h inclusive represent a careful copy of pencil linesi'nade on the face of the plate during actual test. Curve g 'correspondingl therefrom and presents an abutting edge adapted to bear against the bottom of the slots of the rack 2|. The latter is laid upon the bottom of the water pan 20 and is also of inverted V-shaped cross-section with the upwardly -extendingqmarginal edges 22 which also contact with thebottom edges of the tongue portion I5 of the evaporating plate B. Transverse slots 23 are provided at intervals in the rack 2| for spacing the plates B.

I have made the discovery that if the plate is of cumulating and cutting down the pore area until water can no longer pass through the inner pores of the plates as fast as the plates can evaporate it.

A third type of clogging action occurs but. this occurs either in plates not having correct outline or when plates considerably clogged by calcium and magnesium carbonates as described in the preceding paragraph are continued in service. In

' either one of these two cases, the outermost areas of the plates, last to receive the water, become dry. Evaporation then occurs from the innermost areas of the plates, these areas being bounded respec- Y tively by lines defined by mineral salts which are tapered cross-section, thicker at the bottom than edges at top andsides, asindicated by top view Fig. 4, the capillary advance of the water laterally would be more rapid and the curves a to h inclusive Would extend out furtherv laterally. y This means that the plate can be extended laterally substantially as sho-wn `at I2, I3 and III, and still remain as wet in service at the extreme lateral edges as it does `in the rectangular lform of Figs.

1 and 2. In other Words, moreevaporation could be secured per plate without danger of the outer `edges remaining. insufficiently moistfor eicient vevaporating service and durability. The tapering Yof the plate as described not only adds'to the l eflicient evaporation per plate but extends its period of eiiicient service as'will be mode fully explained later.V f

All city supplied water contains dissolvedmineral salts and floating matter such as algae and -ircn oxidesv (rust). All city supplied water passes through iron pipes and the rust so formed by'action of the water and its Ycontents upon the inner walls of the iron mains and pipes. The floating matter in the water enters and clogs the inlet pores of the plates. Y 1 Any mineral salts dissolved in the water freely enters the inlet pores and is carriedV by the capillaryl iiowoutward toward the outeredges of the plates. The water itself is evaporated from the lsurfaces of the plates but the soluble salts accumulate on the outer edges of the plates. As the rapid water evaporation from the surfaces of the platesreduces their temperature, the mineral accumulations on the outer edges of the plates remains soft, porous, moist and easily brushed ofi from time to time-each year or two normally.l

Besides the mineral salts which remain permalnently soluble as above described, city supplied water also contains calcium and magnesium carbonates which remain dissolved in the water if the water also contains carbon dioxide, as is almost invariably'the case. But an action takes place vwhich seems to be as follows: When the water enters the pan where it is warmed somewhat by the warm air circulating around and past the pan and plates, the carbon dioxide begins to escape and continues to doso after the water enters the plates. The calcium and magnesium carbonates can then kno longer be heldin solution by the plates, especially near the inlet end, gradually acdeposited along these lines and block the iiow of Ywater past these lines within the plates.

To prevent the first named ltype of clogging',l that is clogging of the inlet pores of the plate by floating matter in the supplied Water, I havev found it practically imperative to provide a water` filter containing a filter medium composed of the same porous material as the plates. Such a filter medium can be conveniently installed in either of the feed lines 36 or 31. This filtering medium thus passes floating matter that will not clog the inlet pores of the plates but stops floating matter thatl would clog the inlet pores of the plates. The filter is then cleaned from time to time which is very much easier to do than to remove and clean all the plates. s

There will then still remain in the water floating oxides formed by Yaction of the Water upon the inner wall of the metal tubing from the lter to the water pan. This too would clog ther inlet pores of the plate within possiblyv a couple months but to extend this time limit to a full season or two, I provide much greater inlet area such as indicated at I5, than is actually necessary. In this way I am able to extend the active efcient service period of the inlety surface upto a time when internal plate clogging makes attention to vthe 'preceding paragraph and also by the tapern ing of the plate, making .it thicker toward the inlet area, as has been described, this tapering adds considerable to the active service vperiod of theV plate before internal clogging accumulates to the point Where evaporation is impaired, The more rapid and therefore more effective capillary flow induced by the tapering formation also helps 4to extend the active life of the plate for other but not yet known reasons.

In addition to the steps taken asabove described two other steps are taken to cope with internal deposits. I have found that certain sol- Events and acids suchV as hydrochloric acid readily then be washed out with water substantially as if the deposits were sugar. I therefore make the plates of a material which is unaifectedby hydrochloric acid and other calcium or magnesium carbonate solvents. In addition I make theplates of a material having rather coarse capillarity Vto facilitate the washing out process and at the same time provide ample voids for accumulation of inservice period is attained.

ternal deposits so that longest Vpossibleactive I have furthermore discovered thatif, while the plates are in servicey a solvent such as acetic water, consequently they are deposited in the acid or `hydrochloric acid in relatively small and harmless quantity isadded to the water in the ban from time to time, it converts insoluble aceV cumulations in the plates to soluble salts and the capillary iiow within the plates thereupon carries the said accumulations, then in soluble form, to the surface and toward the outer edges of the plates. y

Figs. 6 and 11 illustrate the evaporator as assembled in a heating furnace bonnet or plenum chamber. The guides 25 on the sides o'f the pan 22 engage with the 'support rods 2li which ex'- tend through to the outer wall 2`| of the furnace. A hook bolt 28 connects the inner or right hand end of the pan 20 to the ceiling or top wall 29 of the furnace and is attached by means 'of the nut 3|). As shown in Fig. 10, an extension Strip '23 may be used in the event that the hook bolt is not of sufcient length. Openings 3| and 342 are provided in the inner and outer furnace lwalls 2l and 21' respectively for access to the evaporator pan 20 and plates B. A cover plate 33'e`xtends over the outside vwall opening 3|. A feed pipe 34 leads into the left hand or 'front end of the pan 20 from the feed cup 35. The water supply, if previously controlled, as from a remote control source such as a Water vfeed regulator located in the space to be heated, may beled into the feed cup 35 through the line 36j on the other hand, if the water feed is to be by way of a dib rect control instrument such as indicated at 38. the water feed line 'may be located as indicated at 3l. A water level eii'ualiz'er cup 39 has an air tube 40 which passes through the cover plate 33 and connects the cup 39 with the 'air pressure in the interior of the furnace. The overflow pipe 4| leads lto a drain from the equalizer cup 39..

Referring now to Figs. 12 and 13, my invention also includes means for rapidly increasing the rate of evaporation in proportion to the rate`A of introduction of water to the pan 2D. 'In Fig. `12, the .right hand end of the pan 20 is eleva'teddby means of shortening the support rod 28. In Fig. 13, the supporting 4rack 2| is elevated by means of the lug 42 placed between thebottom of the rack 2| and the bottom of the pan 2|) inthe right hand conditions of demand and operation. By means of varying the distance of the bottoms of the plates B with respect to the waterlevel range; or in other words, by Varying the depthof i'mmersion of the plates, a greatly increased evaporating rate is obtainable in proportionvto the rate of water supply or rate of elevation of the water level. This result is explainable by the factv that there is a substantial difference inthe rat of evaporation by an individual plate between depth of immersion corresponding to a substantial amount of water immersion of the bottom of the plate and to a mere minimum wetting of the bottom of the plate respectively. In other words, when the water level substantially coincides with the bottom of the plate, the evaporating rate of the latter is greatly reduced as compared to its evaporating rate when the water level is higher. As shown in the accompanying drawings, the bottom of the highest plate substantially coincides with the lowest water level, so that such highest plate will at all times receive some wetting action and will thereby not become completely dry. I have found that this relative positioning of the height of the highest plate with respect to the lowest water level is of advantage, since when the datesarepermitted te become alternately wet and dry, there exists a tendency lfor the ereationof increased lime deposits in the plates. The tilting oi the pan such as shown in Fig. 12, efr the tilting.

of water, and an upper portion `extending upwardly and outwardly therefrom, th'e outer. terminal edge of said last-named portion yhaving a contour 'conforming substantially to the line oi advance of water of absorption from said body, said plate being of decreasing cross-sectional thickness from its water contacting portion to said terminal edge.

An evaporating plate composed of a porous material adapted to absorb water, comprising an intermediate lower portion adapted to be inser'ted in a body of water and upper and lateral portions extending upwardly from and to both sides of said intermediate portion, the outer terminal edge of said upper and lateral portions having a contour conforming substantially to the line of advance of water of absorption from` said body of water, said plate being of decreasing Grossa-sectional thickness from its water contacting portion to said terminal edge.

3. A vapor diffusing plate formed of capillary material, and rigid and self-supporting, and comprising a lower portion to be positioned in a body of water and an upper portion to be positioned above the water, and having at least part of said upper portion of less thickness than at least part of 'said lower portion, and th'e margin of said upper portion remote from the body'of waterhaving such contour that water progressing from the body of water will reach all points of said margin substantially simultaneously.

4. In a vaporizing device comprising a recepta- `ele adapted to contain water and having a pair of spaced sides, and a body of water withinsaid receptacle having its surface not above a predetermined level appreciably below the upper edges 'of said sides: a vapor diffusing plate, formed of capillary material, positioned transversely of said sides, and vcomprising a lower portion positioned inr the Water, an upper portion extending upwardly from said lower portion a substantial distance above the upper edges of said sides, said upper portion including oppositely extending lateral portions extending a substantial distance laterally of said sides respectively, and including depending portions extending downwardly from said lateral portions respectively yexteriorly of said sides and vterminating not lower than said predetermined level, thereby to provide additional vapor diffusing area within the non-Siphoning limits of extent.

5. In a vaporizing device comprising a receptacle adapted to contain water and having a pair of spaced sides, and a body of water within said receptacle having its surface not above a predetermined level appreciably below the upper edges of said sides: a vapor diiusing plate, formed of capillary material, positioned transversely of said sides, and comprising a lower portion positioned in the water, an upper 'portion extending upward- 1y from said lower portion a substantial distance above the upper edges of said sides, said upper ally of said sides respectively, and including-depending portions extending downwardly Vf rom said lateral portions respectively exteriorlyr of said sides and terminating not lower than said predetermined level, thereby to provide additional va- I por diffusing area within the non-siphoning limits of extent, and the margin of said upper portion remote from the body of water having such contour that water progressingV from the body of water will reachrall points of said margin, substantially simultaneously.

` above the upper edges of said sides, said upper portion including oppositely extending lateral portions extending a substantial distance laterally of said sides respectively, and including depending portions extending downwardly from said body of water will reach all points of said margin substantially simultaneously. Y

9. A vapor diffusing plate, formed of capillary material, and comprising a lower portion to be positioned in a body of water, and an upper portion to be positioned above the water, said upper portion extending upwardly and laterallyv with respect to said lower` portion to an outer terminal margin remote from the body of water and being lateral portions respectively exteriorly of said sides and terminating not lower than said predetermined level, thereby to provide ladditional vapor diffusing area within the non-Siphoning Ythe upward extent and lateral extent of said upper portion being such and the contour of said margin being such that water progressing `from the body vof water will reach all points of said margin substantially simultaneously.

8. A vapor diffusing plate, formed of capillary material, and ,comprising a lower portion tovbe positioned in a body of water, and an upper portion to be positioned above the water, said upper portion extending upwardly and laterally to both sides with 'respect to said lower portion to an outer terminal margin remote from the body of water, said margin extending Yfrom points up-l Wardly remotest to points laterally remotest from the respective sides of -said lower portion, the upward 'extent and lateral extents of said upper portion being such and the contour of Ysaid margin being such that water progressing from the progressively thinner at successive lines of front ofwater advance, said margin extending from points upwardly remotest to points laterally remotest from sai-d lower portion, the upward extent and lateral extent of said upper portion being such and the contour of said margin being such that water progressing from the body of water will reach al1 points of said margin substantially simultaneously.

10. A vapor diffusing plate, formed of capillary material, and comprising a lower portion to be positioned in a body of water, and an upper portion to be positioned above the water, said upper portion extending upwardly and laterally to both sides with respect to said lower portion to an outer terminal margin remote from the body of water and being progressively thinner at successive lines of front of water advance, said margin extending from points upwardly remotest to points laterally remotest from said lower portion, the upward extent and lateral extent of said upper portion being such and the contour of said margin being such that water progressing from the body of water will reach all points of said margin substantially simultaneously. Y

11. In a vaporizing device comprising a receptacle adapted to contain water and having a pair vof spaced sides, and a body of water within said receptacle having its surface not above a predetermined level appreciably below the upper edges `of said sides: a vapor diffusing plate, formed of capillary material, positioned transversely of said sides, and comprising a lower portion positioned in the water, an upper portion extending upward ly from said lower portion a substantial distance above the kupper edges of said sides, said upper portion including lateral portions extending a substantial distance laterally of said sides, and including depending portions extending downwardly from said lateral'portions respectively exterior-y ly of said sides and terminating not lower than said predetermined level, thereby to provide additional vapor diffusing area within the non-Siphoning limits of extent, said upper portion being progressively thinner at successive lines of front of water advance, and the margin of said upper portion remote from the body of water having such contour that water progressing from the body of water will reach all pointsy of said margin substantially simultaneously.

OTTO J. KUENHOLD, SR.

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