GB1591731A - Degassing apparatus - Google Patents

Description

(54) IMPROVEMENTS IN THE CONSTRUCTION OF DEGASSING APPARATUS (71) We, I.D.S. WATER TREAT MENT LIMITED, of West India House, Baldwin Street, Bristol BS1 1QW, and formerly of 64 Rounceval Street, Chipping Sodbury, Bristol, BS17 6AR, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to liquid degassing apparatus, and has as an object to provide an improved construction of such apparatus.

A known form of degassing apparatus in the United Kingdom comprises a tower filled with packing material, the lower end of the tower being mounted on the top of a sump for the degassed liquid. The liquid containing the gas to be removed is introduced in the top of the tower and falls downwards through the packing. A countercurrent to the liquid flow, comprising air or other gas depending upon the circumstances, is drawn upwards through the tower by a fan. Mass transfer occurs and the desired gas is removed from the liquid. The degassed liquid is collected in the sump at the bottom of the tower. It is normal for the tower to be supported on the lid of the collecting sump, and this puts considerable strain on the lid, which has to be strong enough to carry the static loads and any dynamic loads introduced by tower swaying.

Generally, this arrangement is unsatisfactory.

The present invention provides an improved construction in which the tower extends downwardly through the lid of the sump to the base thereof and is there supported vertically and laterally. The lid of the sump engages the tower, and thus provides a secondary lateral support spaced upwardly from the base support, resulting in a stronger tower construction. However, the additional strength is not advantageous unless it can be utilised. In the present invention, the weight of water in the sump combines the novel.sump and tower construction to give additional stability to the tower, enabling its improved strength to be fully utilised. This effect is not possible in the prior constructions where the tower is supported on the lid of the sump.

In order that the invention may be more clearly understood, one embodiment will now be described with reference to the accompanying drawings, wherein: Figure 1 shows a side view of water degassing apparatus, with the sump in crosssection, Figure 2 shows a cross-section through the apparatus on the line A-A Figure 1, and Figure 3 shows a cross-section through the apparatus on the line B-B of Figure 1.

Referring to the drawings; the degassing apparatus comprises a tower 10 of suitable height (only the upper and lower portions of the tower are shown in Figures 1 and 2). At the top of the tower is mounted a fan and motor assembly 12 which constitutes means for drawing air or other counter-current scrubbing gas up the tower. A sump 14 provided at the lower end of the tower, and comprises a generally rectangular container 16 with a lid 18 secured thereto through flanges 20 at the upper edge of the container. Adjacent one end of the container the lid 18 is provided with a circular aperture through which the tower 10 passes, the lower end of the tower extending as far as the base 22 of the sump. The tower rests on the base and is vertically supported thereby.

An upstanding collar 24 on the base surrounds the bottom end of the tower and provides lateral support. Thus, the tower is maintained in a vertical position by engagement with the collar 24 and the lid 18. The tower is secured to the lid at 26 by welding or other suitable attachment. Just below the lid the tower is provided with a number of apertures 28 for the entry of degassing medium, in this case. air. Apertures 29 are also provided near the bottom of the tower for the: degassed water to pass into the sump. An outlet' conduit 30 is provided in the wall of the sump near the base thereof for. the, removal of degassed water. Means are provided as follows- for delivering water to, be degassed to ,the top of the tower. A vertical riser.pipe 32 extends up the interior of the tower to a point near the top thereof.

The ,bottom end of the riser is closed and rests on the closed bottom of the tower. The upper end of theriser is provided with a header 34 with apertures 36 through which water. to be degassed is discharged from the pipe 32 into the tower. Water to be degassed is fed to the riser 32 through an inlet conduit 38, which extends through the wall of the sump, and is controlled by a valve 40 operated by a float 42 so that the water in the, sump does not normally exceed a maximum level 44. An overflow conduit 46 extends through the wall of the sump at a point above this maximum level 44. The supply of, water to-the sump is provided by a pump, (not, shown). The lid 18 is also provided with an opening 56 for access to the, interior of the sump, with a hinged cover 58,únder the eaves of which are gaps 62 for the entry of air into the sump. There is further provided a port 60 in the lid for the introduction of caustic doses, in accordance with, conventional practice The operation of the degassing tower is as follows. If the level of water in the sump is belo.w.the maximum level 44, the valve 40 is open. The water to be degassed is pumped through the inlet -38- to the riser 32, and emerges-from the header 34 to fall down the tower over:,the packing material contained therein, which,may for example be 38 mm.

plastic Pall (Trade Mark) rings. At the same time,,, the fan assembly 12 draws the degas sing air upwards through the tower via the openings 28 from the air reservoir above the water in the sump. Air can enter the sump through the gaps 62 under the cover 58. The degassed water falls to the bottom of the tower and passes into the sump, from which it isEdrawn off through the outlet 30 by a suitable pump (not shown). A liquid level sensing - -device 48 of conventional type, operating on fixed electrical probes 50, 52, 54, controls the operation of this pump. If the outlet pump is not operating, the degas sed water is stored in the sump.

Apart from- the improved strength and stability of the construction, as indicated earlier, certain other advantages can be obtainçd. No special provision need be made to support the tower packing, which can thet fill the, tower completely. Such support is optional. Since the fall of water is entirely through the packing and contained within the tower walls, there is no splashing, and the surface of water in the sump remains calm, thereby iniproving the operation 9f the liquid level control device. Since the air enters the tower through apertures within the sump,!nó special provision need be made to prevent the exit of descending water through these apertures. Since the vertical riser pipe is contained entirely within the tower, there is no point of entry of the pipe through the tower wall outside the sump, at which point leakage might occur. This arrangement is also mechanically stronger; and any leakages of water will be within the tower, and therefore relatively unimportant.

WHAT WE CLAIM IS: 1. Liquid degassing' apparatus comprising a sump for the liquid and a degassing tower projecting-upwards from the sump, means for delivering liquid to be degassed to the top of the tower and discharging it to fal''l downwards through the- tower, and means for inducing a flow of a scrubbing gas upwards within the tower so that it contacts the des'c'ending - 'liquid', the tow,er .extending downwards through a lid of the sump to the base thereof and being there supported vertically and laterally, the lid of the sump engaging the tower and providing thereby a secondary support 'spaced upwardly from the base support.

2. Liquid degassing apparatus according to claim 1 wherein the bottom of the tower rests on the base of the sump and.is supported laterally by a collar upstanding from the base and surrounding the bottom of the tower.

3. Liquid degassing apparatus according to claim 1 or claim 2 wherein the tower has an aperture near its bottom for discharging degassed liquid into the sump, and an aperture within the top portion of the sump below the lid for the entry of scrubbing gas from the space within the sump above the liquid level.

4. Liquid degassing apparatus according to any one'of the preceding claims wherein' the means for delivering liquid to be degas-, sed to the top of the tower includes a vertical riser pipe entirely contained within the tower.

5. Liquid degassing apparatus, substan- tially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. apertures 28 for the entry of degassing medium, in this case. air. Apertures 29 are also provided near the bottom of the tower for the: degassed water to pass into the sump. An outlet' conduit 30 is provided in the wall of the sump near the base thereof for. the, removal of degassed water. Means are provided as follows- for delivering water to, be degassed to ,the top of the tower. A vertical riser.pipe 32 extends up the interior of the tower to a point near the top thereof. The ,bottom end of the riser is closed and rests on the closed bottom of the tower. The upper end of theriser is provided with a header 34 with apertures 36 through which water. to be degassed is discharged from the pipe 32 into the tower. Water to be degassed is fed to the riser 32 through an inlet conduit 38, which extends through the wall of the sump, and is controlled by a valve 40 operated by a float 42 so that the water in the, sump does not normally exceed a maximum level 44. An overflow conduit 46 extends through the wall of the sump at a point above this maximum level 44. The supply of, water to-the sump is provided by a pump, (not, shown). The lid 18 is also provided with an opening 56 for access to the, interior of the sump, with a hinged cover 58,únder the eaves of which are gaps 62 for the entry of air into the sump. There is further provided a port 60 in the lid for the introduction of caustic doses, in accordance with, conventional practice The operation of the degassing tower is as follows. If the level of water in the sump is belo.w.the maximum level 44, the valve 40 is open. The water to be degassed is pumped through the inlet -38- to the riser 32, and emerges-from the header 34 to fall down the tower over:,the packing material contained therein, which,may for example be 38 mm. plastic Pall (Trade Mark) rings. At the same time,,, the fan assembly 12 draws the degas sing air upwards through the tower via the openings 28 from the air reservoir above the water in the sump. Air can enter the sump through the gaps 62 under the cover 58. The degassed water falls to the bottom of the tower and passes into the sump, from which it isEdrawn off through the outlet 30 by a suitable pump (not shown). A liquid level sensing - -device 48 of conventional type, operating on fixed electrical probes 50, 52, 54, controls the operation of this pump. If the outlet pump is not operating, the degas sed water is stored in the sump. Apart from- the improved strength and stability of the construction, as indicated earlier, certain other advantages can be obtainçd. No special provision need be made to support the tower packing, which can thet fill the, tower completely. Such support is optional. Since the fall of water is entirely through the packing and contained within the tower walls, there is no splashing, and the surface of water in the sump remains calm, thereby iniproving the operation 9f the liquid level control device. Since the air enters the tower through apertures within the sump,!nó special provision need be made to prevent the exit of descending water through these apertures. Since the vertical riser pipe is contained entirely within the tower, there is no point of entry of the pipe through the tower wall outside the sump, at which point leakage might occur. This arrangement is also mechanically stronger; and any leakages of water will be within the tower, and therefore relatively unimportant. WHAT WE CLAIM IS:

1. Liquid degassing' apparatus comprising a sump for the liquid and a degassing tower projecting-upwards from the sump, means for delivering liquid to be degassed to the top of the tower and discharging it to fal''l downwards through the- tower, and means for inducing a flow of a scrubbing gas upwards within the tower so that it contacts the des'c'ending - 'liquid', the tow,er .extending downwards through a lid of the sump to the base thereof and being there supported vertically and laterally, the lid of the sump engaging the tower and providing thereby a secondary support 'spaced upwardly from the base support.

2. Liquid degassing apparatus according to claim 1 wherein the bottom of the tower rests on the base of the sump and.is supported laterally by a collar upstanding from the base and surrounding the bottom of the tower.

3. Liquid degassing apparatus according to claim 1 or claim 2 wherein the tower has an aperture near its bottom for discharging degassed liquid into the sump, and an aperture within the top portion of the sump below the lid for the entry of scrubbing gas from the space within the sump above the liquid level.

4. Liquid degassing apparatus according to any one'of the preceding claims wherein' the means for delivering liquid to be degas-, sed to the top of the tower includes a vertical riser pipe entirely contained within the tower.

5. Liquid degassing apparatus, substan- tially as described herein with reference to the accompanying drawings.