WO2005008071A2

WO2005008071A2 - Gas-liquid separator for pumping systems

Info

Publication number: WO2005008071A2
Application number: PCT/IB2004/002326
Authority: WO
Inventors: Giancarlo Sorgato
Original assignee: Varisco Spa
Priority date: 2003-07-18
Filing date: 2004-07-19
Publication date: 2005-01-27
Also published as: WO2005008071A3; ITVI20030143A1

Abstract

A gas-liquid separator for pumping systems comprises a separation chamber (2) having at least one lower liquid inlet/outlet port (3) and at least one upper gas or air outlet port (4), a float (5) adapted to move vertically within the chamber (2), a valve (6), operated by the float (5), and adapted to put the upper port (4) in fluid communication with external vacuum generating means to facilitate gas discharge from the liquid contained in the chamber (2) and/or to draw in liquid through the lower port main portion (7) having a substantially prismatic inner surface (8). Furthermore, the float (5) is housed in the main portion (7) and has a substantially cylindrical outer surface (9), such as to delimit, with the inner surface (8) of the main portion (7), angular portions (10) for preferentially collecting any suspended solid contained in the liquid.

Description

GAS-LIQUID SEPARATOR FOR PUMPING SYSTEMS

Field of the Invention

The present invention is generally applicable to the field of fluid machines, and particularly relates to a gas-liquid separator for pumps or similar equipments, in accordance with the preamble of claim 1. Background art

A number of embodiments of gas-liquid separators for pumps or stationary or movable pumping systems are known. These apparatuses are widely used to reduce or remove the gases dissolved in the pumped liquid.

US-A-4,775,292, US-A-4, 358, 299, US-A-4, 447, 189 disclose respective gas-liquid separator apparatuses, each including an appropriately shaped chamber, so positioned as to impart vortical motion to the liquid. Gas is forced to the center of rotation of the vortex and is collected in an appropriate discharge duct, whereas the degassed liquid exits from the separator through a second duct, different from the former.

An apparent drawback of these arrangements lies in that vortex generation causes unavoidable liquid energy dissipations, which persist throughout the operation of the separator. Furthermore, this type of separator cannot apply a negative pressure in the liquid suction duct, during priming of the plant in which it is contained.

An additional drawback lies in that, in this type of separators, the gas discharge duct or the liquid duct may be clogged, particularly when the liquid contains suspended solids. Such clogging may affect proper operation of the separator.

DE-A-198 10 005 discloses a gas-liquid separator comprised of a porous liquid filter crossed by the liquid and which has a large liquid contact surface. Any gas bubbles present in the liquid are likely to contact the filter surface and be retained thereby.

An apparent drawback of this solution lies in that the filter causes considerable localized liquid energy losses. Also, the filter requires frequent maintenance to avoid clogging and is nearly unusable with liquids containing suspended solids.

US-A-1,551,362, GB-A-645, 626, GB-A-843,329 and EP-A-1, 024, 293 disclose respective apparatuses for separating one or more gases dissolved in a liquid and/or to prime a corresponding pump. The common feature of these apparatuses is a vertically extending chamber having a lower liquid inlet and an internal float adapted to selectively close at least one valve, depending on the liquid level in the chamber.

Particularly, in EP-A-1, 024, 293 and US-A-1, 551, 362, the float-operated valve selectively puts the upper portion of the chamber in communication with appropriate suction means . Thus, gas is discharged by gravity from the liquid contained in the chamber and is drawn in at the upper wall of the chamber by the suction means. When the chamber is empty or contains a relatively small amount or liquid, the valve is open and the gas contained in the upper portion of the chamber is drawn in. Conversely, when liquid level rises above a predetermined level, the valve is closed, thereby preventing any excessive rise of liquid level.

A drawback of these prior art arrangements lies in that, when liquid contains suspended solids, undesired clogging may occur in the spaces between the float and the inner wall of the chamber. Also, even when solid matter is able to circulate in the spaces between the float and the inner wall of the chamber, an early wear of the float may occur.

An additional drawback of these solution consists in that any sudden change in motion conditions of the liquid entering the chamber or the generation of pressure waves may cause undesired dynamic thrusts on the float. Such dynamic thrusts may stress and damage the float or the mechanism which allows motion thereof.

Summary of the invention

A primary object of this invention is to obviate the above drawbacks, by providing a sturdy and reliable gas-liquid separator.

A particular object is to provide a separator, whose features remain unchanged with time.

A further object of the invention is to provide a separator that can be advantageously used with different liquid types and particularly with liquids containing suspended solids.

Another particular object is to provide a cost-effective separator.

Yet another object is to provide a separator which affords an easy and fast maintenance.

Another particular object is to provide a separator which may be mounted on various kinds of pumps or pumping systems.

These objects, as well as others that will be apparent hereafter, are achieved, according to claim 1, by a gas- liquid separator for pumping systems, which comprises a separation chamber having at least one lower liquid inlet/outlet port and at least one upper gas or air outlet port, a float adapted to move vertically within the chamber, a valve operated by the float and adapted to put the upper port in fluid communication with external vacuum generating means to facilitate gas discharge from the liquid contained in the chamber and/or to draw in liquid from the lower port, characterized in that the separation chamber includes a main portion having a substantially prismatic inner surface, the float being housed in the main portion and having a substantially cylindrical outer surface, such as to delimit, with the inner surface of the main portion, angular portions for preferentially collecting any suspended solid contained in the liquid.

Thanks to this particular configuration the liquid circulation in the separation chamber will be dramatically improved even when suspended solids are contained in the liquid, thereby reducing float wear caused thereby.

Preferably, the main portion has a substantially elongated shape, defining a longitudinal axis, and the separation chamber includes a radially offset lower portion which is connected to the main portion through a transverse connecting portion. Thanks to this particular arrangement, the fluid entering the separation chamber will be forced to follow a relatively tortuous flowpath, whereby any float-damaging dynamic thrust will be considerably attenuated by the radially offset lower portion.

Brief Description of the Drawings

Further features and advantages of the invention will be more apparent from the detailed description of a few preferred, non-exclusive embodiments of a gas-liquid separator according to the invention, which are described as non-limiting examples with the help of the annexed drawings, in which: FIG. 1 is a sectional side view of an embodiment of a separator according to the invention; FIG. 2 is a sectional side view of a second embodiment of a separator according to the invention; FIG. 3 is a sectional view of the separator of FIG. 1. Detailed description of a preferred embodiment

Referring to the above figures, a gas-liquid separator according to the invention is shown, which is generally designated with numeral 1, for use in pumping plants and adapted to be mounted on various pumps of different types and sizes .

Separator 1 comprises a separation chamber 2 having at least one lower liquid inlet/outlet port 3 and at least one upper gas or air discharge port 4. Within chamber 2 a float 5 is housed, which is constrained to move vertically to operate a valve 6 as a function of the liquid level in the chamber 2. Valve 6 is conformed in such a manner as to selectively put the chamber 2 in fluid communication with external vacuum generating means (not shown) through the upper port 4.

The negative pressure that is selectively generated by the external vacuum generating means in the chamber 2 facilitates gas discharge from the liquid contained in the chamber 2.

Also, in the pumping plant priming steps, and anytime that the chamber 2 is emptied, the external vacuum generating means may actively assist in drawing in liquid through the lower port 3 and in filling the pumping plant, by adding their action to the self-priming capabilities of the system pump/s.

According to the invention, the separation chamber 2 includes a main portion 7 having a substantially prismatic inner surface 8. Also, the float 5 is housed in the main portion 7 and has a substantially cylindrical outer surface 9. This latter delimits, with the inner surface 8 of the main portion 7, angular portions 10 of the chamber 2, that are adapted to preferentially collect any suspended solids contained in the liquid.

Each angular portion 10 is substantially delimited by a pair of adjacent sides of the inner surface 8, that form a dihedral angle , and by a corresponding portion of the outer surface 9 of the float 5.

Suitably, the substantially prismatic inner surface 8 of the main portion 7 may have a substantially polygonal cross section. In the embodiment as shown in the drawings, the section is four-sided, so as to define four angular portions 10 of the chamber 2. Particularly, the four-sided section may be square, rectangular or rhomboidal .

The main portion 7 may have a substantially elongated shape, defining a longitudinal axis L. Also, the separation chamber 2 may include a lower portion 11 that is radially offset with respect to the longitudinal axis L and is connected to the main portion 7 through a transverse connecting portion 12.

The lower port 3 may be formed on a bottom wall 13 of the radially offset lower portion 11, so that the entering liquid is forced to follow a relatively tortuous flowpath before reaching the main portion 7.

The radially offset lower portion 11 may also have a top wall 14, opposite the bottom wall 13, which may be possibly equipped with an inspection door 15 to facilitate the cleaning of the lower offset portion 11.

The top wall 14 is positioned and shaped in such a manner as to absorb any dynamic thrust from the liquid entering through the lower port 3.

As shown in the embodiments of the figures, the valve β may include a body 16 having a duct 17 for connection with vacuum generating means.

Furthermore, in the body 16, the valve 6 may include a first frustoconical hollow member 18, adapted to put the connecting duct 17 in fluid communication with the separation chamber 2 and, suitably, also a second frustoconical hollow member 19 adapted to put in fluid communication the connecting duct 17 and the outside.

Float 5 may include at least one shaft 20 adapted to operate the valve β. At least one prismatic pair 21 is further provided to guide shaft 20 along a sliding axis that is substantially parallel to the longitudinal axis L. The prismatic pair 21 causes the float 5 to translate vertically without substantially rotating, thereby preventing any possible contact or impact between the float and the inner surface 8 of the main portion 7.

The valve may include a first ball 22, integral with the shaft 20, which is adapted to obstruct the first frustoconical member 18. When the liquid level in the chamber 2 rises, the float 5 is pushed upwards to a raised position in which the first ball 22 comes in contact with the first frustoconical member 18 and is biased against it. In this configuration, gas passage between the connecting duct 17 and the separation chamber 2 is blocked, to prevent any excessive increase of the liquid level in chamber 2.

The valve may further include a second ball 23, adapted to obstruct the second frustoconical member 19. When the liquid level in the chamber 2 is relatively low, gravity the second ball 23 in contact with the second frustoconical member 19. In this position, the second ball 23 obstructs the cavity of the frustoconical member 19 and prevents any passage of air between the outside environment and the connecting duct 17.

Furthermore, shaft 20 may have a longitudinal end 24 adapted to interact with the second ball 23. When the liquid level in the chamber 2 rises, a longitudinal end 24 of the shaft rises vertically until it touches and lifts the second ball 23, which comes off the second frustoconical member 19, thereby allowing air passage between the outside environment and the connecting duct 17.

Thus, when the liquid level in the chamber 2 rises above a predetermined value, the chamber 2 is isolated from the external vacuum generating means, whereas these latter are put in communication with the outside environment, thereby preventing the liquid level from further rising and the pressure in the connecting duct 17 from dropping excessively.

Conversely, when the level falls below the predetermined value, the external vacuum generating means are put in fluid communication with the chamber and isolated from the outside, thus starting again to exert their action on the liquid in the chamber 2.

Advantageously, in order to further assist cleaning and maintenance in general, the main portion 7 may have at least one discharge orifice 26 near its lower end 25.

This latter orifice may also be used for introducing additional elements or members in the main portion 7, for instance floodgates or stop members to prevent the float 5 from directly contacting the lower end 25 of the main portion 7.

From the above description it clearly appears that the separator according to the invention fulfils the proposed objects and particularly the presence of angular portions considerably improves liquid circulation in the separation chamber, even when liquid contains suspended solids. Moreover, this feature, as well as the fact that the float translates vertically without touching the inner surface of the chamber, reduces float wear, thereby preventing any damage thereto.

The separator of the invention is susceptible of a number of changes and variants, within the inventive concept expressed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

While the separator has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligence of the invention and shall not be intended to limit the claimed scope in any manner.

Claims

1. A gas-liquid separator for pumping systems, which comprises a separation chamber (2) having at least one lower port (3) for liquid inlet/outlet and at least one upper port (4) for gas or air outlet, a float (5) vertically moving within said chamber (2), a valve (6) operated by said float (5) for fluid communication of said upper port (4) with external vacuum generating means to facilitate gas discharge from the liquid contained in said chamber (2) and/or to draw in liquid from said lower port (3) , characterized in that said separation chamber (2) comprises a main portion (7) having a substantially prismatic inner surface (8), said float (5) being housed in said main portion (7) and having a substantially cylindrical outer surface (9), such as to delimit, with the inner surface (8) of said main portion (7), angular portions (10) for preferentially collecting any suspended solid contained in the liquid.

2. Separator as claimed in claim 1, characterized in that said substantially prismatic inner surface (8) of said main portion (7) has a substantially polygonal transverse cross section.

3. Separator as claimed in claim 2, characterized in that said transverse cross section is substantially four-sided.

4. Separator as claimed in claim 1, characterized in that said main portion (7) has a substantially elongated shape, which defines a longitudinal axis (L) .

5. Separator as claimed in claim 4, characterized in that said separation chamber (2) comprises a lower portion (11) that is radially offset and connected to said main portion (7) through a transverse connecting portion (12) .

6. Separator as claimed in claim 5, characterized in that said lower port (3) is formed on a bottom wall (13) of said radially offset lower portion (11) .

7. Separator as claimed in claim 6, characterized in that said radially offset lower portion (11) has an upper wall (14) opposite said bottom wall (13), which is adapted to absorb any dynamic thrust of the liquid entering through said lower port (3) .

8. Separator as claimed in claim 7, characterized in that said upper wall (14) has an inspection door (15) to facilitate the cleaning of said lower offset portion (11).

9. Separator as claimed in claim 1, characterized in that said valve (6) includes a body (16) having a duct (17) for connection with said vacuum generating means.

10. Separator as claimed in claim 9, characterized in that said valve (6) comprises within said body (16), a first frustoconical hollow member (18), for putting said connecting duct (17) in fluid communication with said separation chamber (2) .

11. Separator as claimed in claim 10, characterized in that said valve (6) comprises, within said body (16) , a second frustoconical hollow member (19) , for putting said connecting duct (17) in fluid communication with the outside environment.

12. Separator as claimed in claim 1, characterized in that said float (5) comprises at least one shaft (20) for operating said valve (6), at least one prismatic pair (21) being provided for guiding said shaft (20) along a sliding axis, substantially parallel to said longitudinal axis (L) .

13. Separator as claimed in claims 10 and 12, characterized in that said valve (6) comprises a first ball (22), integral with said shaft (20) , for obstructing said first frustoconical member (18), thereby preventing any passage of gas between said connecting duct (17) and said separation chamber (2) , with said float (5) in a raised position.

14. Separator as claimed in claims 11 and 12, characterized in that said valve (6) comprises a second ball (23), for obstructing by gravity said second frustoconical member (19), thereby preventing any passage of air between the outside and said connecting duct (17) .

15. Separator as claimed in claim 14, characterized in that said shaft (20) has a longitudinal end (24) for lifting said second ball (23) thereby allowing air passage between the outside and said connecting duct (17) , with said float (5) in a raised position.

16. Separator as claimed in claim 1, characterized in that said main portion (7) has at least one discharge orifice (26) near its lower end (25) , to assist maintenance and cleaning.