US2979156A

US2979156A - Vacuum degasifier

Info

Publication number: US2979156A
Application number: US810345A
Authority: US
Inventors: Joseph F Sebald
Original assignee: Worthington Corp
Current assignee: Worthington Corp
Priority date: 1959-05-01
Filing date: 1959-05-01
Publication date: 1961-04-11
Anticipated expiration: 1978-04-11

Description

April 1961 J. F. SEBALD 2,979,156

VACUUM DEGASIFIER Original Filed Dec. 2, 1952 2 Sheets-Sheet 1 JOSEPH F. SEBALD INVENTOR.

W FIGJ W April 11, 1961 J. F. SEBALD VACUUM DEGASIFIER 2 Sheets-Sheet 2 Original Filed Dec. 2, 1952 FIG.3

VACUUM DEGASIFIER Joseph F. Sebald, Bloomfield, NJ assignor to Worthington Corporation, Harrison, N.J., a corporation of Delaware Continuation of application Ser. No. 323,625, Dec. 2, 1952. This application May 1, 1959, Ser. No. 810,345

1 Claim. (Cl. 183---2.5)

This invention relates generally to the degasification of fluids and more particularly to means for maintaining a vacuum degasifying apparatus at substantially uniform total pressure within the apparatus so as to approach the desired equilibrium solubility of the dissolved oxygen and non-condensible gases to be removed.

In apparatus which is used for the degasification of liquids involving primarily the removal of oxygen and non-condensible gases therefrom, generally a tower maintained at low pressures corresponding to the desired equilibrium solubility relationships, is utilized which is divided into a water storage section and a desgasifying section and includes a venting arrangement.

In the degasifying section some means is generally provided such as inter-spaced trays or baflle arrangements or other type of packing arrangements over which the down Wardly injected fluid which is to be degasified must pass whereby the fluid is broken up into droplet form, which increases the total surface area and reduces the ratio of volume to surface to allow the oxygen and non-condensi bles to escape more easily from the fluid.

It has been found in connection with such packing arrangements that unless suitable vapor flow lanes are provided in and about the packing portion of the degasifying section of the tower and between the packing and the air outlet connections, in those systems applying the suction to the uppermost or venting end of the tower there will exist a pressure difference above and below the packing. Hence, for systems where there are no vapor flow lanes it is necessary to produce extremely low pressures at the outlet connections requiring very large vacuum pumps in order to compensate for the pressure differences resulting from the restricted gas and vapor flow passages through the packing in the tower.

The present invention accordingly defines and covers a packing arrangement for a degasifier which provides flow passages to maintain the degasifier at a substantially equal total pressure in the portion thereof throughout the packing and the containing vessel whereby a relatively small steam jet ejector or a relatively light vacuum pump can be used for withdrawing the oxygen and non-condensibles removed from the fluid being deaerated to obtain the necessary degree of purity of effluent as may be required for the specific industrial purpose. 7

It is anobject of this invention to provide a degasifier with a substantially uniform total pressure throughout its entire vapor space. i

It is another object of the present invention to provide a degasifier with a packing arrangement having vapor flow lanes therein in direct connection with the air and vapor outlet.

7 various features of construction and combination of parts,

which will be first described in connection with the accompanying drawings, showing a vacuum degasifier of a preferred form embodying the invention, and the feabottom of the condensate trap Patented Apr. 11, rear tures forming the invention will be specifically pointed out in the claim.

In the drawings:

Figure 1 is a side elevation partly in section of the invention.

Figure 2 is a top view of the invention.

Figure 3 is a section taken on line 3-3 of Figure 1.

Figure 4 is a section taken on line 44 of Figure 3.

Referring more particularly to the drawings, Figure 1 shows a vacuum deaerator comprising an elongated fully encloser tower 1 having formed therein a water storage section 2 and a degasifying section 3.

Raw water or other fluid is brought into the tower 1 through a raw water inlet pipe 4- from a source (not shown). The raw water inlet pipe 4 extends transversely of the vertical axis of the tower 1 near the upper end of the deaerating section 3 of the tower 1 and is provided with distributing conduits 5 positioned substantially perpendiculariy thereto in a horizontal plane and in some suitable pattern such as is shown in Figures 2 and 3 of the drawings. This allows fluid to be discharged downwardly into the degasifying section 3 from spray valves 6 formed in spaced relation to each other on the distributing conduits 5 as is also clearly shown in Figures 1, 2 and 3 of the drawings.

Above the raw water inlet pipe 4 at the uppermost point is a vent outlet 7 which is connected to'a suitable suction device (not shown) such as a steam jet ejector or vacuum pump both easily purchasable on the open market and Well known in the art. They act to reduce the pressure in the tower 1 to a point consistent with the desired degree of purity of the efiluent fluid to be obtained.

Surrounding the vent outlet 7 is an annular partition or bafile 8 which is connected to the inner wall 9 of the upper end of the tower 1. The annular partition 8 extends down into a condensate trap 10 which is a shallow cylindrical pan-like vessel also connected to the inner wall 9 and having openings 11 so that vapor or gases will move in a convoluted flow from the degasifying space 3 to the vent outlet 7, as is clearly shown in Figures 1 and 2 of the drawings.

A liquid sealed condensate return 12 is provided in the 10 to return condensate by gravity flow downwardly through the degasifying space 3 of the tower 1.

The vacuum producing means will maintain the tower 1 at the reduced pressure consistent with required performance. Raw water will be sprayed out of the spray valves 6 indroplet form and will drop by gravity through a spray confining baffle 13 mounted in the degasifying space 3 below the raw water inlet pipe 4, as is clearly shown in Figures 1 and 2 of the drawings, which directs the fluid on a packing arrangement generally designated 14 which provide means for increasing or maintaining the injected water in its droplet form.

The bafile 13 is, of course, mounted so that a vapor flow space 15 is maintained in the degasifying section 3.

The packing arrangement 14 is substantially in gross appearance in rectilinear box-like form. However, it is not a solid but contains many convoluted vapor flow pasarrangement consists of a series of layers of spaced slats or trays 16. The layers are spacedfrorn'each other by transverse spaced support members 17 which are joined to the layer of slats or trays 16 immediately above it by suitable means such as threaded members 18 all of which is clearly shown in Figure 4' of the drawings. Thevarious layers of slats or trays 16 are from layer to layer oflfset from each other so that every other layer has its slats or'trays 16 in alignment with each other and fluid will thus fall or drip from the slats of one layer onto those of the layer directly below it by gravity flow until the droplets join the fluid being stored in the storage space 2 of the tower 1; A discharge outlet 19 is provided for the water storage at the lower end of the tower 5 1 from which degasified water can be removed by gravity or to which the suction of a pump (not shown) can be connected. I 4 Where necessary about the outer periphery of the various layers of slats or trays a splash edging 20 is provided to redirect stray droplets of fluid inwardly towards the central portion of the packing, as is clearly shown in Figures 1, 3 and 4 of the drawings.

Figures 1, 2 and 3 further show that the packing arrangement 14 is square in the horizontal cross-section and 15 when mounted in the cylindrically-shaped tower will provide vapor flow passages 21 between the inner wall 9 of the sides of the tower 1 and the outer periphery of the packing arrangement which will be open at the bottom thereof to the water storage space 2 and are continuous throughout theapparatus promoting maximum degasifica- 1 tion of the fluid for the specific pressure that is produced in the degasifying space by the pressure reduction apparatus.

Where there is a packing arrangement in the degasifying space which does not make provision for unrestricted vapor flow passages between the portion of the degasifying space above the packing and the spaces either within or below the packing, there will be during operation a significant dilference in pressure in the space above the packing and the space below the packing due to the frictional engagement between the downflowing water and 40 upflowing water vapor and non-condensible gases.

In packing arrangements with no provision for vapor flow passages if P represents the pressure applied to the outlet or venting arrangement, then in the space above the packing arrangement the total pressure at the given temperature will be equal to P,,, while the pressure P will represent the pressure below the packing arrangement, which pressure will be greater than F, by an increment A P which is significant because the partial pressure .of'=-' the vapor and non-condensible gases will depend upon the pressure and temperature conditions. AP, represents the increment in pressure which occurs due to the frictional engagement between the downflowing water and upflowing water vapor and non-condensible gases where there are no vapor flow passages provided.

The effect of providing vapor flow passages, as in the present structure, is to make the value of AP approach zero, and as AP approaches zero the pressure P of the space below the packing arrangement will approach the" pressure P of the space above the packing arrangement,

thusgiving a uniform total pressure tothe degasifying space and thereby producing the advantages and results of the present invention. I his clear from the above that where vapor flow lanes are provided' as against such equipment that does not 5 have vapor flow lanes provided, the vacuum producing equipment would the case where vapor flow lanes are provided be relatively light as compared with those used in equipment with no vapor flow lanes; This was clearly shownaboveas in apparatus where no vapor lanes are provided AP is significant and in such equipment where vapor flow lanes are provided this significant value is eliminated. Hence the equipment necessary for producing the vacuum is relatively light.

In operation raw water or fluid is led from a source not shown through the raw water inlet 4 into the degasifying space 3, where it is'discharged downwardly from the distributing conduits 5 and nozzles 6 through the bafile 13 onto the packing arrangement 14 whence it drips from layer to layer of the slats 16 releasing water vapor and non-condensible gases to the vapor collecting spaces. The effluent water is collected below the packing arrangement 14 in the water storage space 2 and will be drawn therefrom through the discharge outlet 19 for use.

While one form of the invention has been illustrated and described, it is obvious that those skilled in the art may vary the details of construction as well as the precise arrangement of parts and it is understood therefore that the invention is not to be limited to this arrangement but may be widely modified within the invention defined by the claim.

What is claimed is:

In a vacuum degasifier, a cylindrical tower forming a degasifying section in the upper end thereof and a water storage section at the lowermost end thereof, inlet means for delivering fluid to said tower at the upper end of said degasifying section for flow therein by action of gravity, a fluid directing element of substantially square horizontal cross-section mounted in said tower about the inlet means to direct fluid delivered from said inlets toward the center of said degasifying space, said fluid directing element mounted in spaced relation to the inner wall of said tower to form vapor flow spaces therebetween which vapor flow spaces communicate at their upper ends with said vent means, packing at substantially square horizontal cross-section in said degasifying section mounted therein in spaced relation to and between the outlet end of said fluid directing element and the water storage section to receive fluid from said inlet means, vertical vapor flow passages formed along the length of said packing and said vapor flow passages between the outer periphery of said packing and said tower, said vapor flow passages connected at their upper ends with said vapor flow spaces and opening at their lower ends into the degasifying space above said water storage section whereby substantially uniform total pressure may be maintained in said degasify- .ing section, said packing including a plurality of stacked slats forming a plurality of stacked lateral passageways through the length of said packing, said passageways directly connected at one of their ends with said vertical flow passages to coact therewith to maintain substantially -uniformtotal pressure in said degasifying section, and

means for venting oxygen and non-condensible gases centrally-located in the uppermost end of said tower and equidistantly spaced from said vapor flow spaces to coact therewith to provide for uniform flow of said non-condensible gases out of said vacuum degasifier.

References Cited in the file of this patent j UNITED STATES PATENTS 7 Carrier May 4, 1915 1,508,985 McDermet Sept. 16, 1924 1,758,566 Elliott May 13, 1930 2,068,094 Webre n Jan. 19, 1937 2,353,138 'Beach July 14, 1944 2,677,433 Kretzschmar May 4, 1954 FOREIGN PATENTS Germany .1 Sept. 26, 1921