US 1790911 A
Description (OCR text may contain errors)
Feb. 3, 1931. sou 1,790,911
I WATER DEAERATION Filed Dec. 19, 1921 11 filq ATTORNEY Patented Feb. 3, 1931 j UNITED STATES PATENT OFFICE GEORGE H. GIBSON, F MONTOLAIR, NEW JERSEY, ASSIGNOR TO COCHRANE CORPORA- TION, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA WATER DEAERATION Application filed December 19, 1921. Serial No. 523,547.
The general object of the present invention is to provide an improved method of and apparatus for eliminating air from water heated to a moderate temperature which may be appreciably below 212 F., though in some cases the Water may be heated to a higher temperature.
My invention is particularly adapted for use in the treatment of boiler feed water 0 which it is desirable to preheat moderately by the use of exhaust steam as well as to deacrate, and I preferably carry out my invention by the use of a deaerating and preheating device which is in efi'ect an open feed water heater though differing in some respects from, and comprising features of con struction and arrangement not found in, standard types of open feed water heaters.
In carrying out my invention I proceed 2 on the principle that for the practical, commercial deaeration of water for boiler feed and analogous purposes it is not only necessary to subject the water to temperature P and pressure conditions "which will suitably' 2 reduce the capacity of the water to hold air in solution, but that it is also necessary to subject the water to mechanical agitation in order to liberate the air from the'water at a reasonably rapid rate without subjecting itto undesirably high temperature and vacuum conditions. My invention comprises a novel method of, and novel apparatus for obtainingthe desired mechanical agitation of the water.
The various features of novelty which characterizemy invention are pointed out with particularity in the claimsannexed to and forming a part of this specification. For a better understanding of my invention, how- 4 ever, and the advantages possessed by it.
reference should be had to the accompanyin drawings and descriptive matter in which I have illustrated and described preferred formsof my invention.
of the drawings:
prising a float E provisions of Fig. 1; and
Fig. 7 is a partial sectional elevation taken similarly to Fig. 1 and illustrating a modification of the apparatus shown in that figure.
In the drawings, and referring first to construction shown in Figs. 1 and 2, A represents the heating and deaerat-ing device proper which is in the form of a tank divided into lower and upper compartments A and A respeetivelyby a partition B. Mounted on the partition 1s a set of inclined baflies or water spreading trays C which are enclosed and supported by abox-like frame C open at top and bottom, and communicating at its lower end with the compartment A through an opening B in the partition B. I
The water to be deaerated is su trough C from which the baflies C as in an ordinary open feed water heater. The supply of water through the p1pe D is controlled by a valve D which is ad usted to constantly maintain approximatelythe water level indicated in the compartment A, the regulating means comworking in the float tank E and connected through the rock shaft E and link D to the valve D. The float tank'E is connected to the compartment A above and below the water level therein.
Mounted in the compartment A above the water over ows onto pplied through a pipe D which dischar es into a water level in the latter, are two seriesof water spreading trays or baflies F onto which the'water falling from the trays C in the compartment A is discharged. Water is also discharged onto the trays F from a conduit G which extends downwardly from the trays F nearly to the bottom of the compartment A. The conduit G is shown as formed by spaced apart vertical plate-like members G which extend horizontally across the tank. As shown the upper ends of the plates G form the supports for the adjacent edges of the corresponding trays F. A bafile F above the conduit G diverts water fallirrg from the trays C away from the conduit and partly to one, and partly to the other of the two sets of trays F. The plates G have their lower ends G2 spread apart to enlarge the conduit, and in this enlargement of the conduit is located a horizontally disposed steam spray pipe H provided with discharge ports H opening upwardly in line with the conduit G. Steam, which may be exhaust steam or live steam, is supplied to the pipe H through a pipe I advantageously provided with a non-return valve J, a manually controlled cut ofi valve K, and a valve L automatically actuated to regulate the supply of steam to the tank A in response to conditions Within the heater by suitable automatic control mechanism.
As shown in Figs. 1 and 2, the automatic control mechanism for the valve L is responsive to the temperature of the body of water in the lower portion of the tank A. This mechanism as shown comprises a bulb N located within the tank and containing a volatile liquid which may be water and is connected externally of the tank to an expansible element shown as a bellows element N. The movable end of the bellows N carries a valve N which opens and closes the exhaust port M of. a fluid pressure motor M accordingly as the temperature to which the bulb N is subjected rises to or falls below a predetermined temperature. The fluid pressure motor M is in the form of a pressure chamber having a flexible side wall M to which the stem of the valve L is connected. A suitable pressure fluid as compressed air is continuously supplied to the motor M through the supply conduit M which contains a restricted orifice M With this arrangement; when the exhaust port M is closed, the pressure in the motor M quickly builds up to the extent required to close the valve L, and when the exhaust port M is open the pressure in the motor M is decreased to "permit the valve L to open under the action of the spring M The air,liberated in the apparatus is withdrawn from the compartment A through a pipe P connected to a suitable exhauster P which may be a dry air pump. Anywater of condensation which may collect in the imately constant water level in the compartment A Steam is admitted to the bottom of the compartment A through the pipe I as required to maintain the body of water in the lower portion of the compartment A at the desired temperature by means of the thermostatic control provided for the automatic steam supply valve L. The conduit G with the steam pipe H arranged in it form a steam water lift or jet pump for moving water from the bottom of the tank upward through the conduit G and onto the trays F over which it moves in film-like and broken streams back into the pool or body of water in the bottom of the compartment A. The uncon-' densed steam, and the air liberated in the compartment A passes out of the latter and into the compartment A through the space traversed by the film-like and broken streams of water moving downward over the trays C. This water, the average temperature of which is below that of the water in the compartment A, tends to condense the steam passing out of the compartment A, and in practice the apparatus should bd so operated and proportioned that only a relatively insignificant portion of vapor will be carried out of the compartment A through the pipe through the conduit formed by the open end- I ed housing C for the trays C. The discharge I of steam into the body of water in the lower portion of the compartment A, and the move ment of this water upward through the conduit G and on to the-tray; F is to subject the water to a reboiling or scrubbing effect. This scrubbing effect and the passage of the water back to the bottom of the tank in filmlike and broken streams, contribute to the .rapid liberation of air mechanically entangled or entrained in the water, but not of the tray box C in which the bulk of the actually held in solution therein. The rate at which the air passes out of the solution and is separated from the water depends of course upon the temperature and pressure maintained in the apparatus.
With the apparatus shown in Figs. 1 and 2 the air liberated within the tray box C is prevented from entering the compartment A y the upward flow of steam and air into the lower end of the box. Thefact that a large portion of the air liberated in the apparatus is thus prevented from entering the compartment A is desirable as the greater the accumulation of air in the compartment A the more difficult it is to liberate the small remaining content of air in the water co1lecting in the lower portion of the compartment.
The advantage obtained by the trays C increase with the degree of vacuum maintained as the volume occupied and consequently the number of air bubbles formed by a given weight of air increases with the vacuum and thus increases the difficulty of separating the air from the water.
A further advantage resulting from the use water heating effect occurs is the consequent protection of the shell of the tank A from sudden and more or less local'temperature changes resulting from momentary variation in the relative amount of water to be heated and available steam for heating it, and the splashing of comparatively cold water against much hotter metal plates. With the described construction these local temperature variations are almost wholly restricted to the trays C and to the tray box C which is a separate mechanical structure from the tank A. If these temperature variations result in cracking the trays C or tray box C no particular harm is done, whereas a crack in the shell of the tank A renders the apparatus inoperative, particularly when a considerable vacuum is maintained within the tank, because of the resultant air leakage.
With the thermostatic control provided the temperature in the apparatus will be approximately constant and will depend upon the adjustment of the thermostatic control mechanism for the valve L. The pressure in the apparatus above the water level in the compartment A will be approximately that of water vapor at the temperature of the water in the lower portion of the compartment A provided the exhauster is effective, as it should be to prevent any appreciable accu mulation of air in the appa atus.
In the modified form of apparatus shown in Fig. 3 a. single set of trays CA are located in the upper portion of the heating and deaerating tank AA. The water to be deaerated is discharged on to the trays CA through a valve DT, pipe D, and overflow trough C as in Fig. 1. In this form of my invention steam for heating and scrubbing the water is supplied to the heater through a manifold HA located near the bottom of the tank and well below the water level therein and comprising branches Heach having a plurality of, small discharge orifices in its upper side. An inclined baffle R located above the water level in the tank AA and below the trays CA, and provided with a depending extension R forms a means for carrying the water falling from the trays CA down toward the bottom of the tank AA to a level below that of the manifold HA. To insure a substantial and directed circulation of the body of water in the tank AA, I arrange a vertical baille S in the tank, at one side of the manifold HA with its upper edge below the water level and with its lower edge above the bottom of the tank. lVith this arrangement steam discharged through the manifold HA tends to circulate the water in the direction of the arrows shown in Fig. 8. Steam is supplied to the apparatusshown in Fig. 3 through a switch valve Q having two outlets Q and Q and having an inlet Q, which may be connected to a suitable source of live or exhaust steam. An oscillating valve member Q forms a means for closing either of the two ports Q or Q while leaving the other port wide open, and in an intermediate position the valve Q partially throttles each of the outlets Q and Q The valve outlet Q is connected to the inlet of the manifold HA by a pipe Q advantageously provided with a cut off valve K and a non-return valve J.
In the normal contemplated mode of operation of the apparatus shown in Fig. 3, the valve member Q, closes the outlet Q of the valve Q, and all of the steam supplied to the apparatus is admitted to the latter through the manifold HA and is utilized in scrubbing, and setting up of a circulation of, the water in the bottom of the tank AA. The steam rising from the surface of the water and the air swept along with it pass upward to the air exhaust connection P through the space traversed by the raw water produced by injecting steam into thewater.
through a manifold HA at a temperature appreciably above thatof the water into which the'steam is discharged. It will be apparent, of course, that a valve like the switch valve Q may be employed with the apparatus shown' in Fig. 1. The switch valve arrangement shown in Fig. 3, while novel with me, is not claimed herein but is claimed in my copending application, Serial No. 528,546, filed of even date herewith.
In Fig. 4 I illustrate a modification of the apparatus shown in Figs. 1 and 3, in which trays CA are arranged in the top of the tank AB as in Fig. 3, and a second set of trays FA are located between the trays CA and the level of the water in the lower portion of the tank. In Fig. 4 the internal conduit G of Fig. 1 is replaced by an external steam jet pump conduit T into which steam is discharged in an upward direction through an orifice in the steam spray pipe T. The lower end of the conduit T is connected to the tank AB adjacent the bottom of the lat ter, and the upper end of the conduit T extends into the tank AB and discharges into the overflow trough'F provided above the trays FA and receiving not only the discharge from the conduit T, but also the water falling from the trays CA. To improve the steam and water mixing effect, the lower portion of the conduit T is enlarged and vanes or bafiies T are provided above the spray pipe T. With the apparatus shown in Fig. 4, the conduit T may be made of wrought iron or the like, and so designed; and proportioned as to resist water hammer strains. The water is circulated through the conduit T, as through the conduit G in the construction first described.
In lieu of controlling the supply of steam to the heating and deaerating chamber by thermostatic valve mechanism as in Fig. ,1, I may advantageously employ an automatic steam supply control valve mechanism responsive to the pressure in the deaerating chamber. Forms of valve mechanism for this purpose are shown in Figs. 5 and 6. The steam supply control valve LA shown in Fig. 5 comprises a cylindrical valve chamber L having a lateral steam inlet port L and steam outlet ports L Flow through the latter is controlled by a piston valve L in the chamber L which is connected by an upwardly extending stem to a balancing piston L of the same diameter as the-valve L The valve L is subjected at its under side to the pressure in the deaerating chamber A by means of a connection L leading from the chamber to the closed lower end of the valve chamber L. The upper end of the valve chamber L is open to the atmosphere so that the upper end of the piston L is subjected to the pressure of the atmosphere. A lifting force opposing the pressure of the atmosphere on the piston L is exerted on the latter by a lever L connected to the piston and provided with an adjustable counter weight L With the described construction, the valve L and piston L are balanced against the In Fig. 6 I have illustrated a modification of the valve mechanism shown in Fig. 5. In the valve chamber L of the: valve LB, a piston L is located above the steam inlet port L and is exposed at its upper end to the atmosphere and is connected to a lever L carrying a counter balance weight L as in Fig. 5. Flow through the valve LB is controlled by a valve member L in the form of a disc moving away from its seat into an enlargement L of the chamber L The enlargement L forms the outlet chamber of the valve, and is directly connected to the spray pipe through which the steam is discharged into the deaerating chamber. The pressure in the valve outlet chamber L depends, of course, upon the pressure in the deaerating chamber. The valve mechanism shown in Fig. 6, while in some respects simpler than that shown in Fig. 5, is in general less desirable because the pressure in the valve chamber L while dependent on, will not always be exactly proportional to the pressure in the deaerating chamber. While the steam controlling valve mechanisms shown in Figs. 5 and '6 are directly'responsive to the pressure in the deaerating chamber, they are also responsive to the temperature therein since the pressure in the vapor space of the chamber is normally the pressure of water vapor at the temperature of the body of water in the chamber. The steam controlling valve mechanisms of Figs. 2, 5, and 6 are all alike in that they prevent the introduction of steam to the deaerating chamber in excess of the amount required to maintain a maximum desired temperature therein which ordinarily will be appreciably beldw 212 F. The non-return valve J in the steam supply connection to the deaeratwater hammer. The water hammer or hydraulic shock then produced is caused by the total collapse of steam bubbles injected into the water whereby water currents traveling in opposite directions are brought into violent collision and thus produce enormous local pressures. The pressure waves thus formed travel outward from the points of collision through the mass of' water and these pressure waves may be sufiiciently severe to rupture the shell of the chamber A and to break pipes and pipe joints, especially when the shell and pipe connections are made of cast iron. To damp out such pressure Waves I may place a shock absorbing barrier or barriers in proximity to the point or points at which the water hammer is initiated, and thereby eliminate or substantially minimize water pressure fluctuations transmitted to the wall of the heating chamber.
For example, as shown in Fig. 7 the side walls G of the steam'lift conduit G may be formed with air chambers G? in their lower ends adjacent the level at which steam is discharged from the pipe H. The innerwalls Gr of the air chambers G should be made thin enough to have some flexibility. With this arrangement the pressure waves generated in the conduit G when the Water therein is substantially colder than the steam discharged by the pipe H setup vibrations in the flexible walls G of the air chambers G The vibrations of the flexible walls G15 are not transmitted to any appreciable extent across the air chambers, and in consequence but a small portion of the pressure wave disturbances set up within the conduit G are transmitted to the shell of the heater. The provisions of the air chambers Gr with their flexible inner walls also protect the jet conduit itself against injury from water hammer.
While in accordance with the provisions of the statutes I have illustrated the best methods of and apparatus for carrying out my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of my invention without departing from its spirit as set forth in the appended claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.
Having now described my invention, what I claim as new and desire to secure by Let- Y tersv Patent, is:
1. Apparatus for deaerating water, com-' prising in combination a closed chamber provided with an air outlet and a water outlet, means automatically responsive to the amount of water in said chamber forsupplying water to said chamber as required to maintain a body .of water therein partially filling the chamber, a set of trays or baflies located in the chamberabove the body of water, and means for injecting steam into and provided with a water outlet opening from the lower compartment, a conduit con necting said compartments, a series of water trays or bafiles in said conduit, means for passing water into the lower compartment through said conduit in film-like and broken streams without sealing the conduit against air flow from the lower compartment into the upper compartment through the conduit, and
maintaining a body of water partly filling said lower compartment, means for withdrawing air from the lower compartment through said conduit, and steam supply means located below the normal water level in said lower compartment for heating and scrubbing the water therein.
3. Apparatus for deaerating water comprising in combination a closed chamber having a water outlet and an air outlet, means for supplying water to be deaerated to said chamber to maintain a body of water therein partially filling the chamber, and means for supplying steam to the chamber to scrub and heat the water, comprising an open ended steam lift conduit vertically disposed in said chamber with its lower end immersed in said body of water and formed with elastic internal walls and means for discharging steam upwardly in the lower immersed portion of said conduit.
4. Apparatus for deaerating water comprising in combination a closed chamber having a water outlet and an air outlet, means for supplying water to be deaerated to said chamber to maintain a body of water therein partially filling the chamber, and means for supplying steam to the chamber to scrub and heat the water comprising an open ended steam lift conduit vertically disposed in said chamber with its lower end immersed in said body of water and formed with an air chamber in its walls, the inner walls of said air chamber being flexible, and means for dis charging steam upwardly in the lower immersed portion of said conduit.
5. Apparatus for deaerating water comprising in combination a closed chamber divided into upper and lower compartments and provided with an air outlet opening from the upper compartment and a water outlet opening from the lower compartment, a conduit connecting said compartments and filling said lower compartment, a series of water spreading trays or battles in said conduit over which the Water passing through the conduit flows in film-l ke and broken streams, steam supply means located below the normal water level in said lower compartment for heating and scrubbing the water therein.
6. Apparatus for heating and deaerating water comprising a tank, a bank of water spreading trays located in an upper portion of the tank, water supply means discharging onto the top of said bank of trays, a second bank of water spreading trays located in an intermediate portion of the tank beneath the first mentioned trays and receiving water at its upper end from the upper bank of trays in divided streams distributed over a substantial horizontal area, means responsive to the accumulation of water in a lower portion of the tank for regulating said water supply means so as to maintain a water level in the tank below the lowermost bank of trays,
means for supplying steam to the intermediate portion of the tank in which the lower bank of trays is located, and battle means located out of the path ofthe water passing from the upper trays onto the lower bank of trays for guiding the flow of steam passing over the upper trays and effective in normal operation to normally prevent downflow of steam from the space surrounding the upper trays, and means for withdrawing air from said upper portion of the tank.
7. Apparatus for deaerating water comprising in combination, a tank forming a closed chamber, means for withdrawing air from the upper portion of said chamber, means for withdrawing water from a Water storage space formed in the lower portion of said chamber, means for automatically supplying water to be deaerated to said chamber in accordance with the variations in level of the water in said storage space from a predetermined value, nieans in the upper portion of said chamber for breaking up the.
entering water into a plurality of divided streams distributed over a substantial horizontal area of said chamber, means fortinjecting steam into the bodyof water in said storage space below the water level therein, and a flow directing baffle arranged adjacent said steam injecting means in said storage space for directing the water circulation induced by the injection of steam 1n1t1ally away from and subsequently back towards said steam injecting means.
Signed at Philadelphia, in the county of Philadelphia and State of Pennsylvania, this fourteenth day of December, A. D. 1921.
GEORGE H. GIBSON.