US3399871A

US3399871A - Bubbling valves of liquid-phase and gaseous-phase exchange apparatus

Info

Publication number: US3399871A
Application number: US565205A
Authority: US
Inventors: Bon Pierre
Original assignee: Compagnie des Ateliers et Forges de la Loire SA
Current assignee: Compagnie des Ateliers et Forges de la Loire SA
Priority date: 1965-07-28
Filing date: 1966-07-14
Publication date: 1968-09-03
Anticipated expiration: 1985-09-03
Also published as: FR1452216A; DE1542069A1; BE684642A; GB1148464A; NL6610570A

Description

Sept. 3, 1968 P. BON- 3,399,871

BUBBLING VALVES OF LIQUID-PHASE AND GASEOUS-PHASE EXCHANGE APPARATUS Filed July 14. 1966 2 Sheets-Sheet 1 Sept. 3, 1968 P. BON 3,399,871

BUBBLING VALVES OF LIQUID- ASE AND GASEOUS-PHASE EXCHANGE A P RATUS Filed July 14, 1966 2 Sheets-Sheet a Fig. 7

3,399,871 Patented Sept. 3, 1968 United States Patent Olfice Claims. (e1. 261 -114 ABSTRACT OF THE DISCLOSURE Bubbling valve for liquid-phase and gaseous-phase exchange apparatus consisting of a relative thin disk formed with rectilinear slots disposed "tangentially on a circle concentric to said disk and adapted to reduce priming and providing a self-centering effect.

This invention relates to bubbling valves of the type utilized in the trays of gaseous-phase and liquid-phase exchange apparatus. With these valves the transfer conditions, in comparison with conventional systems such as cylindrical or rectangular caps, or perforated trays, are improved considerably. Moreover, as these valves are easily manufactured by punching and stamping, they constitute an economical proposition.

However, these valves are frequently objectionable because they are scarcely adapted to properly divide the gas or vapour in the liquid mass, and furthermore they are attended by a considerable degree of priming whereby the trays must be spaced to a substantial extent from each other. Moreover, the valves remain locked in their upper or open position, thus causing an imperfect operation of the tray when working conditions are restored. I

It is the essential object of the present invention to provide bubbling valves capable of producing a tangential dispersion of the vapour phase in the liquid phase, whereby a maximum utilization of the tray surf-ace can be achieved. Tangential dispersion imparts to the gaseous jets a horizontal speed component whereby priming is reduced to a substantial extent. Moreover, at very low gas outputs and when the apparatus is stopped the geometrical configuration of the valve according to this invention ensures a satisfactory fluid-tightness of the tray to the liquid loads acting thereupon. Furthermore, slots formed in the valve according to an arrangement constituting an essential feature of this invention provide a leakage path through these valve slots, thus providing a better equilibrium and preventing the valve from jamming during its vertical translation in the tray aperture, which is a frequent occurrence in other types of valves.

According to a specific feature of this invention, the valve consists of a disk in which slots disposed along one or a plurality of circles concentric to the disk axis are formed. If these slots are disposed on a plurality of concentric circles their number may vary, but preferably the different concentric circles will have the same number of slots and these slots will be distributed in staggered relationship between adjacent circles. The number of these slots may advantageously be three per circle. The concentric series of slots lie on a plane somewhat raised with respect to the valve edge and the slots themselves lie at different levels, the differences in level being of the order of 1 to 5 mm.

This invention is also concerned with exchange trays equipped with bubbling valves of the type broadly set forth hereinabove which are disposed on the tray according to a triangular, square or rectangular mesh pattern.

In order to afford a clearer understanding of this invention and of the manner in which the same may be carried out in practice, a typical form of embodiment of the valve constituting the subject-matter of this invention will now be described by way of example with reference -to the attached drawings, in which:

FIGURE 1 illustrates in side elevational and partsectional view the bubbling valve in its closed position;

FIGURE 2 is a plane view of the valve shown in FIGURE 1;

FIGURE 3 is a perspective view of the same valve;

FIGURE 4 is a cross-sectional view of the valve;

FIGURE 5 is a diagram showing a curve plotting the loss of pressure as a function of the velocity of the gas flowing through the valve;

FIGURE 6 is another diagram showing the curve plottingthe valve efficiency as a function of the gas flow velocity; z

FIGURES 7, 8 and 9 are plane views showing various patterns of the apertures formed in-the exchange trays, each aperture being equipped with a valve, and

FIGURE 10 is a fragmentary elevational and sectional view of an exchange apparatus equipped with trays comprising bubbling valves according to this invention.

In the form of embodiment illustrated in the drawing the valve consists of a disk 1 of relatively reduced thickness, for example 1 to 3 mm., in which

slots

2 and 2a are punched along two concentric circles disposed at different levels, said slots being arranged in staggered relationship from one circle to another. The valve is fitted on the tray 3 and guided by lugs 4 extending through a circular aperture 5 formed in the tray. In its upper or open position the valve has its stroke limited by lateral extensions 6 of said lugs. The permissible stroke a-b of these disks may be of the order of 5 to 20 mm.

The bubbling valve according to this invention operates as follows:

The tray utilizing these valves is disposed like a conventional exchange tray in that the stream of liquid pouring from the overflow-chute of the upper tray flows through the set of valves and overflows into the chute leading to the underlying tray. These trays may comprise one or more liquid circulation paths. The trays may be held in the columns through any suitable and known means.

Assuming that a tray 3 is loaded with liquid at a level adjusted as a function of the chute level, the gas or vapour is bubbled at a moderate output rate through the

slots

2 and 2a of the valve 1 without lifting the latter and causing any leakage of liquid (FIGURE 1). This ensures a satisfactory operation of the complete exchange tray and of the column as a whole for low outputs, as contrasted with valves constructed according to a different geometry. As the gas or vapour output increases, the valve is gradually lifted and assumes the upper position shown in FIGURE 4. This height is limited by the lateral extensions 6 of guiding lugs 4, in the upper valve position the major portion of the gaseous stream or jet flows through the space A between the valve and the tray. One fraction of this gas or vapour flows through the

slots

2 and 2a (FIGURE 4) to form radial jets intersecting the main jet and producing a dispersion effect, and at the same time the main jet is deflected in a horizontal direction, whereby the complete surface of the tray will become operative while reducing considerably any priming effect.

The valve according to this invention is characterised by the following advantages:

The permissible output through the trays equipped with valves according to this invention exceeds that of conventional trays under comparable conditions of operation and dimensions;

The pressure drop increment (FIGURE 5) as the gas output increases is considerably lower.

As the gas throughout increases the pressure drop increm entKF IGURE. 5) is considerably lower than that observed with conventional apparatus. Thus, for instance, the pressure drop A varies from 30 mm. of water column to 50 mm. of water per tray when the gas speed v changes from 0.3 to 2 m./s. in a tray tested with air and water, this speed v being measured under empty column shaft conditions.

The efiiciency E (FIGURE 6) is increased due to the nearly complete utilization of the tray surface for bubbling gas through the liquid and may attain or even in certain cases exceed 100% of the theoretical efficiency expressed according to the Murphee method. For a given gas output the efficiency is improved notably by the reduction in the priming. This priming reduction permits on the other hand of reducing the relative spacing of the trays and therefore the height of the columns as much as 20% of the height of columns equipped wih conventional bell or valve trays having a different geometrical arrangement. Moreover, the range'of operation under satisfactory conditions of efiiciency is increased as the valves are not prone to jam in their upper position due to the self-centering action caused by the gaseous flow through the

slots

2 and 2a.

FIGURE 7 illustrates an exchange tray 3 comprising holes 5 disposed according to a square-mesh pattern, each hole being equipped with a valve.

FIGURE 8 illustrates a modified form of embodiment wherein the holes are disposed according to a rectangularmesh pattern.

FIGURE 9 shows a modified structure wherein the holes are disposed according to a triangular-mesh pattern.

FIGURE 10 illustrates in section a distillation column 10 comprising trays 3 equipped with valves of the abovedescribed type. The liquid delivered from the chute 12 of the upper tray 3 fiows through the valve assembly and overflows into the next chute 13 from which it is directed towards the next tray. In this FIGURE 10 the arrows show the direction of circulation of the gas or vapour flowing through the valves and bubbling through the liquid.

What I claim is:

1. A bubbling valve for a gas liquid contact apparatus '4 consisting. of a relatively thin disk formed with a plurality of rectilinear slots disposed tangentially on a plurality of imaginary circles concentric to said disk, the slots on a first circle being spaced radially inward from the slots on a second circle and the slots on a given cricle being staggered with respect to slots on adjacent circles, said disk being adapted to reduced primingand providing a selfcentering effect.

2. The valve of claim 1 wherein the valve is provided with depending guide lugs adapted to extend through a corresponding valve aperture in a tray of the apparatus, said guide lugs having lateral extensions for limiting the permissible vertical stroke of the valve.

3. The valve of claim 1 wherein the slots are vertically disposed at different levels.

4. In a gas-liquid exchange apparatus, a tray equipped with bubbling valves of the type set forth in claim 1.

5. As a novel industrial product a gas liquid exchange apparatus equipped with trays having a bubbling valve consisting of a relatively thin disk formed with slots disposed tangentially on a plurality of circles concentric to said disk, said slots being disposed at different levels, each circle comprises three slots the slots of one circle being shifted inrelation to those of the adjacent circles, said disk being also formed with depending guide lugs adapted to extend through a corresponding valve aperture formed in the tray of the apparatus, said lugs being formed with lateral extensions for limiting the permissible vertical strokes of the valve.

References Cited UNITED STATES PATENTS 3,056,592 10/1962 Thrift 2611 14 3,143,582 8/1964 Jones et al. 261114 3,162,701 12/1964 Joor 261114 FOREIGN PATENTS 645,354 7/ 1962 Canada. 1,237,299 6/1960 France.

vHARRY B. THORNTON, Primary Examiner.

E. H. RENNER, Assistant Examiner.