US1540179A - Apparatus for the deaeration of boiler-feed water - Google Patents

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June 1925- 1,540,179

D. B. MORISON APPARATUS FOR THE DEAERATION 0F BOILER. FEED WATER Filed Sept. 21, 1921 INvENT K: w

' DONALD 6.MOI?I$0N Patented June 2, 1925 UNITED STATES PATENT OFFICE.

APPARATUS FQR THE DEAERATION OF BOILER-FEED WATER.

Application filed September 21, 1921. Serial No. 502,188.

To all whom it may concern:

Be it known that I, DONALD Bangs Mom- SON, of Hartlepool, in the county of Durham, England, have invented a certain new and useful Improvement in Apparatus for the Deaeration of'Boiler-Feed Water,

of which the following is a specification.

This invention relates to the deaeration of boiler feed and other water.

It is well known that air in boiler feed Water promotes corrosion within the boiler system including tubular economizers or heaters, and that numerous devices are at present in use for deaerating the Water.

Water such as condensate from a main condenser under vacuum contains air and other gaseous impurities and for that reason it is not desirable to discharge it directly back to the boiler system. If, however, this water is heated to or near to boiling point at a given pressure, as by a steam jet for instance, some of the air escapes.

It is well known that if aerated water is sufficiently heated as by means of steam, air will be liberated; it is also well known that air in feed water is absorbed by bringing the water into contact with iron or other corrodible material and that the corrosion is impeded if the water contains oil.

In modern high pressure steam systems and especially in steam turbine systems having high steam pressure in the boilers and high vacuum in the condenser, it is of ever increasing economic advantage to deprive the water of all its oxygen and to minimize the volume of its remaining non-condensible gases as by so doing notonly is corrosion in the boiler structure and connections practically prevented but the volume of noncondensible gases passing into the condenser is reduced whereby the vacuum producing efficiency of the condenser is increased and a smaller air pump or its equivalent is required.

The object of my invention is to deaerate the boiler feed water to a degree greater than is usual in steam engine plants and the principle involved in my invention is the employment in succession of the dual effects of air liberation and discharge resulting from heating, and of air absorption resulting from intimate surface contact with oxidizable material.

My invention consists, therefore, in subjecting water to be purified to the action of heat-whereby a percentage of air or gasis liberated and discharged and further subjecting the water to the action of a neutralizing agent such as steel iron or like shavings whereby the remaining oxygen is absorbed. The desired effects may be obtained in a desired sequence. The sequence I prefer is to obtain the liberation effect to be followed by the absorption effect, as this sequence prolongs the activity of a given amount of oxidizable material.

In practice I propose to provide means for maintaining the surface activity of the neutralizing material, such means consisting, in general, in providing a carrier preferably removable for the neutralizing agent and providing, it may be, additional carriers and means whereby one which has been used can be renewed and cleansed and replaced by another which has previously been so treated.

This is of great importance because in steam engine practice oil is usually present in feed water and if oily water passes over the oxidizable material a film of oil gathers on its surface and lessens the intimacy of contact and the corrodible activity. In order to neutralize this bad effect the material of contact, such as metal shavings, may, as. before mentioned, be contained in suitable carriers, a suitable arrangement being adopted whereby they may be removed singly when desired and immersed in a cleansing solution such as a soda bath, which effectively cleanses the surfaces, a spare cleansed carrier taking the place ofrthe one removed.

In the accompanying drawings I have i1- lustrated my invention diagrammatically as applied to the treatment of boiler feed water.

In these drawings Fig. 1 is a diagram illustrating apparatus for carrying out my invention interposed between a condenser and the boiler feed pumps. Fig. 2 illustrates one method of providing for the renewal and regeneration of the neutralizing agent without interference with the continuity of the treatment, and Fig. 3- shows how multiple circulation through the deoxidizing agent is provided for.

Referring to these drawings the numeral 1 designates a condenser and 2 designates the condensate pump which delivers condensate from the condenser to a deaerat ing apparatus wherein a considerable proportion of the air is removed. the water being subjected to the action of the steam heating nozzle 3, the liberated air escaping by the pipe 4, and the partially deaerated water passing off by the pipe 5 through the deoxidizing chamber 6, which is supplied with carriers containing the neutralizing agent such as steel or iron Shavings. The arrangement for liberating air by the aid of the steam nozzle 3 is an important feature of my invention. The form of nozzle I prefer to employ is described in the speci-' fication .of British Letters Patent No. 11690 of 1910.

On reference to Figs. 1 to 3 of the drawings it will be seen that the aerated water to be treated flows into the deaerating apparatus and is delivered to the steam heating nozzle 3 which is so formed that thin streams of water meet thin streams of steam whereby the water is heated locally and in such a manner and with such effect that air or gas is liberated and the column of heated water with its accompanying air bubbles flows through the ap yaratns in stream lines upwardly whereby the air bubbles pass at considerable velocity through the surface of the water, the air being delivered into the hood or air receiver and passing off by the pipe 4 from which it is discharged to the atmosphere, or otherwise where desired, the water flowing downwardly through an extension of the receiver and then upwardly to the discharge pipe 5.

In the arrangement illustrated the de aerator is placed at a considerable distance above the feed pump and admits of the deaerated water being raised to 212 F. or above, but it above 212 F. the escape of air and vapor from the deaerator.

In this example the heated and some of the deaerated water flows from the receiver and mixes with the incoming aerated Water the mixture flowing to the nozzle 3.

The air receiver may also be maintained below atmospheric pressure ifso desired by any suitable means.

Within the deoxidizing chamber 6 a chemical reaction proceeds, the remaining oxygen in the water reacting with the iron or steel which becomes oxidized. From this chamber the water passes off by the pipe 7 to the feed pump 8 practically free of oxygen.

The importance of this dual treatment of condensate will be. understood when it is mentioned that tests have shown that condensate, after deaeration treatment by a heating nozzle to a temperature of 175 F. at atmospheric pressure still contains oxygen. If the two treatments, i. e. deaeration by means of a heating nozzle in a vessel atsuitable temperature and pressure and further treatment by reaction with iron are carried out in series there is no measurable trace of oxygen left in the water and it passes to the boiler feed pumps to all intents and purposes free of oxygen.

In order to provide for a continuous process I propose to provide the apparatus wit b means whereby while some ofthe neutralizer carriers are in situ in the deoxidizing chambers 6, others are in position in a cleansing chamber T which may contain a suitable cleansing agent and I propose to provide a suitable lifting tackle whereby these carriers can be easily manipulated.

The water entering the deoxidizing vessel may pass through the deoxidizing agent direct to the outlet but according to iny invention there may advantageously be intermediate recirculation through the deoxidizing vessel or a portion thereof, as, for example, in Fig. 3 water from the deoxidizing vessel is recirculated through the deaerating vessel whereby the deoxidizing effect of a given quantity of deoxidizing agent is increased. In the example Fig. 3, the recirculating effect is produced by the action of the steam jet but any suitable means for promoting recirculation may be employed.

The utility of this dual treatment of condensate is very considerable, for example a given quantity of average condensate at 1th F. taken from the surface condenser under vacuum of a steam turbine plant was found to contain l of gas, and was delivered direct into a heat deaerator and when raised at atmospheric pressure to a temperature of 180. fully 90% of its contained gas was liberated and discharged. The water then passed through the deoxidizing chamber from which it flowed to the feed pump to all intents and purposes entirely free from oxygen, a result impossible to obtain by heating only, at the temperature set forth, and equally impossible to obtain by oxidation only.

I declare that what I claim and desire to secure by Letters Patent is 1. Apparatus for degassing boiler feed water, comprising a vessel into which the water to be treated flows, means for heating the. water in said vessel, whereby the bulk or" the contained gases are liberated, means for recirculating partially treated water back again to the inlet to said vessel. an outlet for the escape of the liberated gases from said vessel, a second vessel having an inlet to which the partially degassed water flows, an outlet from said second vessel, and means for supporting oxidizable material within said vessel between the inlet thereto and the outlet therefrom, whereby the partially degassed water is finally deozidized during its passage through said second vessel.

2. Apparatus for degassing boiler feed water, comprising a vessel into which the water to be treated flows, means for heating the water in said vessel, whereby the bulk of the contained gasses are liberated, an outlet oxidizable material through which the parfor the escape of the liberated gases from tially deaerated water flows to a final outlet. said vessel, a second vessel to which the par- 5. A deaerator for treating water or other tially degassed water flows, an outlet from liquid in which the water is separated ofi said second vessel, means for supporting oxand deaerated provided with one or more idizable material within said vessel between pipes or passages open at the top containthe inlet thereto and the outlet therefrom, ing nozzles which are supplied with multiple whereby the partially degassed water is streams of water and steam whereby succesfinally deoxidized during its passage sive films of water nearest to the streams of through said second vessel, and means for I steam are preferentially heated to or near to recirculating water from the second vessel the temperature of maximum air liberation back again to the first vessel. and together with the liberated air in the 3. Apparatus for degassing boiler feed form of bubbles flow through the pipe in i water, comprising a vessel .into which the upward stream lines at such velocity that supporting oxidizable material within said Water to be treated flows, a steam heating the air bubbles are delivered through the nozzle located in the bottom of said vessel surface of the water upwardly into a hood designed to promote stream lines of upward or receiver enclosing the pipe like structures flow, an outlet for the escape of the liberated and thence to the atmosphere, the water gases from said vessel, a second vessel to overflowing downwardly into a water sealed which the partially degassed water flows, an 1 extension of the receiver from which it is outlet from said second vessel, and means for led where desired. i

6. Apparatus for heating and deaerating vessel between the inlet thereto and the outliquids comprising an open ended structure let therefrom, whereby the partially dethrough which the water to be heated flows, gassed water is finally deoxidized during its a steam heating nozzle operating to promote passage through said second vessel. stream lines of upward flow in said struc- 4." Apparatus for heating and deaerating ture, a hood or receiver enclosing said strucliquids, comprising .an open-ended structure ture and having an outlet for the escape of through which the water to be heated flows, liberated air and means for causing a proa steam heating nozzle operating to promote portion of the water heated and deaerated steam lines of upward flow in said structure in the structure to recirculate without cona hood or receiver enclosing said structui e tact with air or other water and mix with and having an outlet for the escape of libthe inflowing comparatively cold and erated air and means for causing a proporaerated Water prior to or during its passage tion of the water heated and deaerated in the through the structure whereby the datum structure to recirculate without contact with line of temperature within the structure is air pr other water and mix with the infl0w raised and the release of air facilitated, subing comparatively cold and aerated Water stantially as specified. prior to and during its passage through the In witness whereof I aflix my signature. structure, and a second vessel containing DONALD BARNS. MORISON.

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