GB1602183A

GB1602183A - Tower packing element

Info

Publication number: GB1602183A
Application number: GB272778A
Authority: GB
Original assignee: LEVA M
Current assignee: LEVA M
Priority date: 1978-05-24
Filing date: 1978-05-24
Publication date: 1981-11-11

Description

(54) TOWER PACKING ELEMENT (71) I, MAX LEVA, a citizen of the United States of America of 1, Hodgson Avenue, Pittsburgh, Pal5205, United States of America, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a novel tower packing element for use in random poured packed beds in towers and columns, to bring about mass and heat transfer in gas absorptions, dis tillations, reactors and similar apparatus extensively used in chemical and physical operations.

The most commonly used packings for such purposes are various sizes of rings and saddles.

Although widely used these packings all suffer from the same shortcomings, namely, they will not really form truly physically stable packed beds. Thus, in the randomly poured beds composed of rings and saddles, the pieces are not truly individually interlocked and will, therefore, with time, continue to shift and settle in the towers. This shortcoming has the obvious disadvantage that the flow resistance, which these beds will offer to the fluids that are passing through them, will steadily increase. Pressure drops and energy requirements for pumping are, therefore, very difficult to predict in advance, for such packings, with any great degree of assurance, because these quantities are forever changing.

Another severe shortcoming of the various ring and saddle packings is due to the fact that the beds, formed by these packings, are not truly homogeneous in their texture.

With rings, one always finds large numbers of the pieces aligned in tandem arrangement.

This tandem arrangement is particularly objectionable because a channel is thus formed that is ideal for passing the liquids downwardly, and the liquids are thereby often entirely separated from the gas phase that moves along somewhere else. This separation of flows, which is virtually impossible to control and prevent, is one of the reasons why the contacting efficiencies of these packings are not accurately predictable. Furthermore, this separation of the phases results, in all instances, in a low contacting efficiency. With saddles, the pieces tend to "nest", which is a generally accepted term with saddles, to indicate the pieces will build up into stacks, the individual pieces fitting into each other snugly and preventing large portions of the packing surface from becoming accessible to the flowing liquid and gas phases. Obviously, nesting is, therefore a major cause of poor contacting efficiency.

Thus it is seen that the usual ring and saddle packings offer, in their randomly dumped beds substantial regions of high and low local packing densities. As already stated, this undesirable sit uation leads to channeling of the liquids and hence to actual physical separations of the gas and liquid phases. The result is that these packings are much less effective to bring about heat and mass transfer between the liquid and gas or vapour phases than could be achieved if the packings would not encourage this separation.

The present invention relates to a modification of improvement of the invention set forth in the Complete Specification of U.K. Patent No 1562402. In that specification was described a tower packing element comprising an open-ended curved strip having an integral tongue struck out from the strip to leave a slot therein and extending away from the plane of the curved strip.

The material of which the packing element was proposed to be constructed was any metal or plastics sheeting, clay or ceramic product or other that permits the formation of the elemen by various means.

In the Provisional Specification of my U.K.

Patent Application No 20098 (Serial No 1602182) I have described a tower packing element comprising an open-ended curved strip having a plurality of tongues struck out from the strip and each extending inwardly of the curveature of the strip, the tongues being arranged in a row extending longitudinally of the strip, and the lengths of the tongues being chosen such that they all lie substantially between the curved strip and the chord that extends between the two ends of the strip, and such that the free end of one of the tongues at an intermediate position in the row is located on or closely adjacent to said chord.

Since each tongue of the constructions disclosed in those specifications was formed from the material of the strip, the length of each tongue was determined by the length of the associated slot. This placed substantial restrictions upon the possible configurations of the tongue and slot.

According to the present invention a tower packing element comprises a open-ended curved strip provided with at least one aperture, and a tongue integral with the strip and extending inwardly of the curvature of the stirp from one circumgerential end of the aperture, the length of the tongue being greater or smaller than the circumferential length of the aperture.

Preferably the tongue is greater in length than the aperture.

Preferably the element is formed by moulding from any suitable material such as a plastics or a ceramic.

Polypropylene is a convenient material for many applications.

The strip is preferably formed with at least one circumferentially extending row of apertures, and said one aperture preferably constitutes an intermediate aperture of the row.

Integral tongues may extend from one or both circumferential ends of all or only some of the apertures.

Preferably there are two parallel rows with three apertures in each row, and the tongues associated with the apertures at at least one end of each row are shorter in length than the circumferential length of the associated apertures.

Preferably the curved strip extends through an arc of 1800 or less, and the tongues all lie within the space bounded by the curved strip and a chordal plane extending between the ends of the strip.

The strip is preferably provided with an integral projection which prevents stacking of two elements.

The projection conveniently comprises a post directed radially inwardly from a central portion of the strip and extending substantially to a chord joining the free ends of the strip.

When the strip is provided with two parallel rows of apertures and said one aperture comprises a central aperture of each row, the tongues associated with the central apertures of the rows are arranged such that, when viewed in the axial direction of the strip, they cross each other.

Each tongue may be either straight or curved.

The free ends of the strip and/or the free ends of said one tongue may be serrated to increase the number of possible points of contact with adjacent elements.

The strip may be provided along its circumferential edges with one or more integral reinforcing ribs, and preferably each rib extends radially inwardly of the strip.

A preferred packing element moulded from polypropylene and a modification are shown in the accompanying drawings in which: Figure 1 is a side elevation of the element; Figure 2 is a cross-section on the line 2-2 of Figure 1; and Figure 3 is a view similar to Figure 2 but of a modification.

The element of Figures 1 and 2 comprises a part-cylindrical strip 1 extending for an arc of less than 1800 and provided with a radially inwardly directed rib 2 along each circumferential edge. The free ends of the strip are formed with teeth 3 to provide a large number of contact points with adjacent elements.

The strip 1 has two parallel circumferentially extending rows of oblong-rectangular apertures 4a, 5a, 4b, 5b, the reference letter a designating apertures of one row, and the letter b those of the other row. The apertures 4a, and 4b are shorter in circumferential length than the apertures 5a and 5b.

Long tongues 6a and 6b extend from opposite ends of the apertures 5a and 5b respectively so that they cross when viewed as in Figure 2.

It will be seen that the lengths of the long tongues 6a and 6b are substantially greater than the circumferential lengths of the apertures Sa and 5b.

Short tongues 7a and 7b extend from the ends of the apertures 4a and 4b respectively that are adjacent to the circumferential ends of the strip. Thus in each row tow tongues extend generally in one direction whereas the other tongue extends generally in the opposite direction. The lengths of tongues 7a and 7b are shorter than the circumferential lengths of apertures 4aand4b.

The long tongues 6a and 6b are formed with teeth 8 at their free ends to provide additional points of contact with adjacent elements.

A central radial post 9 prevents stacking of the element with an identical element.

It will be seen from Figure 2 that all the tongues, and the post 9, lie between the strip 1 and a chord extending between the free ends of the strip.

In the modification of Figure 3 the long tongues 6a and 6b are each curved and preferably taper downwardly in thickness towards their free ends. One end tongue 10a, 10b of each row is longer than the corresponding tongue 7b, 7a at that end of the other row and is longer than the corresponding aperture 4a, 4b respectively. In this case the tongues 7a and 10b cross when viewed as in Figure 3, as do the tongues 7b and 10a.

Some of the features of the illustrated packing elements are described and claimed in the Complete Specification of my copending Patent Application No. 20098/77 (Serial No 1602182) WHAT I CLAIM IS: 1. A tower packing element comprising an open-ended curved strip provided with at least one aperture, and a tongue integral with the strip and extending inwardly of the curvature of the strip from one circumferential end of the aperture, the length of the tongue being greater or less than the circumferential length of the aperture.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the material of the strip, the length of each tongue was determined by the length of the associated slot. This placed substantial restrictions upon the possible configurations of the tongue and slot. According to the present invention a tower packing element comprises a open-ended curved strip provided with at least one aperture, and a tongue integral with the strip and extending inwardly of the curvature of the stirp from one circumgerential end of the aperture, the length of the tongue being greater or smaller than the circumferential length of the aperture. Preferably the tongue is greater in length than the aperture. Preferably the element is formed by moulding from any suitable material such as a plastics or a ceramic. Polypropylene is a convenient material for many applications. The strip is preferably formed with at least one circumferentially extending row of apertures, and said one aperture preferably constitutes an intermediate aperture of the row. Integral tongues may extend from one or both circumferential ends of all or only some of the apertures. Preferably there are two parallel rows with three apertures in each row, and the tongues associated with the apertures at at least one end of each row are shorter in length than the circumferential length of the associated apertures. Preferably the curved strip extends through an arc of 1800 or less, and the tongues all lie within the space bounded by the curved strip and a chordal plane extending between the ends of the strip. The strip is preferably provided with an integral projection which prevents stacking of two elements. The projection conveniently comprises a post directed radially inwardly from a central portion of the strip and extending substantially to a chord joining the free ends of the strip. When the strip is provided with two parallel rows of apertures and said one aperture comprises a central aperture of each row, the tongues associated with the central apertures of the rows are arranged such that, when viewed in the axial direction of the strip, they cross each other. Each tongue may be either straight or curved. The free ends of the strip and/or the free ends of said one tongue may be serrated to increase the number of possible points of contact with adjacent elements. The strip may be provided along its circumferential edges with one or more integral reinforcing ribs, and preferably each rib extends radially inwardly of the strip. A preferred packing element moulded from polypropylene and a modification are shown in the accompanying drawings in which: Figure 1 is a side elevation of the element; Figure 2 is a cross-section on the line 2-2 of Figure 1; and Figure 3 is a view similar to Figure 2 but of a modification. The element of Figures 1 and 2 comprises a part-cylindrical strip 1 extending for an arc of less than 1800 and provided with a radially inwardly directed rib 2 along each circumferential edge. The free ends of the strip are formed with teeth 3 to provide a large number of contact points with adjacent elements. The strip 1 has two parallel circumferentially extending rows of oblong-rectangular apertures 4a, 5a, 4b, 5b, the reference letter a designating apertures of one row, and the letter b those of the other row. The apertures 4a, and 4b are shorter in circumferential length than the apertures 5a and 5b. Long tongues 6a and 6b extend from opposite ends of the apertures 5a and 5b respectively so that they cross when viewed as in Figure 2. It will be seen that the lengths of the long tongues 6a and 6b are substantially greater than the circumferential lengths of the apertures Sa and 5b. Short tongues 7a and 7b extend from the ends of the apertures 4a and 4b respectively that are adjacent to the circumferential ends of the strip. Thus in each row tow tongues extend generally in one direction whereas the other tongue extends generally in the opposite direction. The lengths of tongues 7a and 7b are shorter than the circumferential lengths of apertures 4aand4b. The long tongues 6a and 6b are formed with teeth 8 at their free ends to provide additional points of contact with adjacent elements. A central radial post 9 prevents stacking of the element with an identical element. It will be seen from Figure 2 that all the tongues, and the post 9, lie between the strip 1 and a chord extending between the free ends of the strip. In the modification of Figure 3 the long tongues 6a and 6b are each curved and preferably taper downwardly in thickness towards their free ends. One end tongue 10a, 10b of each row is longer than the corresponding tongue 7b, 7a at that end of the other row and is longer than the corresponding aperture 4a, 4b respectively. In this case the tongues 7a and 10b cross when viewed as in Figure 3, as do the tongues 7b and 10a. Some of the features of the illustrated packing elements are described and claimed in the Complete Specification of my copending Patent Application No. 20098/77 (Serial No 1602182) WHAT I CLAIM IS:

1. A tower packing element comprising an open-ended curved strip provided with at least one aperture, and a tongue integral with the strip and extending inwardly of the curvature of the strip from one circumferential end of the aperture, the length of the tongue being greater or less than the circumferential length of the aperture.

2. A tower packing element as claimed in

Claim 1 and formed by moulding.

3. A tower packing element as claimed in Claim 2 and formed of polypropylene.

4. A tower packing element as claimed in any of the preceding claims in which the strip is formed with at least one circumferentially extending row of apertures which includes said one aperture.

5. A tower packing element as claimed in Claim 4 in which said one aperture is an intermediate aperture of the row.

6. A tower packing element as claimed in Claim 4 or Claim 5 in which there are two parallel rows of apertures with three apertures in each row, and the tongues associated with the apertures at at least one end of each row are shorter in length than the circumferential lengths of the associated apertures.

7. A tower packing element as claimed in any of the preceding claims in which the curved strip extends through an arc of 1800 or less, and each tongue lies within the space bounded by the curved strip and a chordal plane extending between the ends of the strip.

8. A tower packing element as claimed in any of the preceding claims in which the strip is provided with an integral projection so arranged to prevent stacking with an identical element.

9. A tower packing element as claimed in Claim 8 in which the projection comprises a post directed radially inwardly from a central portion of the strip and extending substantially to a chord joining the free endsj of the strip.

10. A tower packing element as claimed in Claim 5 or any of Claims 6 to 9 each as appended to Claim 5 in which the strip is provided with two parallel tows of apertures and said one aperture comprises a central aperture of each row, the tongues associated with the central apertures of the rows being arranged such that, when viewed in the axial direction of the strip, they cross each other.

11. A tower packing element substantially as described with reference to Figures 1 and 2 of the accompanying drawings.

12. A tower packing element substantially as described with reference to Figure 3 of the accompanying drawings.