GB2171617A

GB2171617A - Gas-water separator

Info

Publication number: GB2171617A
Application number: GB08603476A
Authority: GB
Inventors: Katsuji Fujiwara; Takeshi Yokoyama
Original assignee: TLV Co Ltd
Current assignee: TLV Co Ltd
Priority date: 1985-02-15
Filing date: 1986-02-12
Publication date: 1986-09-03
Also published as: MX162860B; SE8600605L; GB8603476D0; NO860514L; CH669985A5; IT8619385A0; NL8600375A; FI860551A; DK163568B; DK163568C; ATA35686A; CN86100622B; IN165862B; SE8600605D0; AU562086B2; CA1284773C; ES8700952A1; FR2581892A1; NZ214810A; AU5184686A

Abstract

A gas-water separator has a generally cylindrical partition wall member 34 disposed to form an annular space 37 between the member 34 and a casing 6, 8 located outside the member 34. Swirl-inducing vanes 38 are disposed in the annular space, which is connected to an inlet 22, a separating chamber 7 having a drain valve 43, 44 for separated water and a gas outlet 23. Each vane 38 includes a radially projecting longitudinal wall portion 39, an obliquely downwardly inclined wall portion 40 and a spiral wall portion 41 connected at their lower ends to a radial end wall portion 42. <IMAGE>

Description

SPECIFICATION Gas-water separator Field of the Invention The present invention relates to a separator to be attached to a pipe for gas such as vapor or compressed air to separate water (e.g. condensate) from the gas to the exterior. Particularly, it is concerned with a gas-water separator for separating gas and water from each other by the action of a centrifugal force induced by rotating fluid.

In this type of a gas-water separator, fluid is rotated at an upper portion within a casing and water drops contained in gas are shaken out to the outside by the action of the resulting centrifugal force and thereby separated. The gas is passed to an outlet side, while the separated water drops are discharged to the exterior of the casing through a drain valve disposed in a lower portion within the casing.

Prior Art In accordance with the construction of a conventional gas-water separator, a cylindrical partition wall member is disposed in an upper portion within a casing to form an annular space between the partition wall member and the casing located outside the partition wall member; a multitude of obliquely downwardly inclined rotary vanes are disposed radially in the annular space; and upper and lower portions of the annular space and an inside bore of the partition wall member are connected to an inlet side, a drain valve portion and an outlet side, respectively. In this construction, fluid from the inlet is rotated in the annular space by the rotary vanes, so that the water drops are shaken out to the outside by the action of a centrifugal force. The water drops thus separated flow down and are discharged to the exterior through the drain valve.In a central part of the rotating stream the gas movestowardsthe outlet sidethrough the inside bore of the partition wall member.

Problem to be Solved by the Invention In the above conventional structure, the water drops are only partially carried to the outlet side even if the rotating flow is strengthened and it has been impossible to enhance the gas-water separation efficiency beyond a certain degree.

The reason is that the process is merely predicated on the law of nature that when fluid is rotated, fluid is forced more outwardly by the action of a centrifugal force as its mass is larger, so very small water droplets turn in from the outside to the inside along the surface and consequently are carried to the outlet side together with gas.

The technical subject of the present invention consists in the use of additional means for catching water drops and positively expelling these to the outside in a gas-water separator provided with rotary vanes.

Means for Solving the Problem According to the solution proposed by the present invention for the above problem, obliquely downwardly inclined walls and spiral walls are formed on an outer peripheral wall of a cylindrical partition wall member which spiral walls each project gradually outward from an uppertoward a lower end of each said inclined wall and connected stepwise to a radial end wall at the lower end of the inclined wall.

Operation of the Apparatus According to the Invention The above technical means lead the following function.

An annular space is formed over the outer periphery of the cylindrical partition wall member and the obliquely downwardly inclined walls are positioned in the annular space, so fluid is changed in moving direction into an obliquely downward direction when passing through the annular space.

Consequently, the fluid rotates in the annular space because of its continuity and this rotation extends to above and below the inclined walls, that is to say, the fluid enters the annular space while rotating and goes out also under rotation.

Since the spiral walls are projecting outward gradually from to upper ends to the lower ends of the inclined walls, the fluid moves more outward than corresponds to a direction tangential to the annular space and is blown in a better condition against an inner wall of a casing located outside.

Further, since the width of the annular space becomes smaller toward the lower ends from the upper ends of the inclined walls, the speed of the rotating flow increases gradually and reaches a maximum at the lower end portion.

Moreover, since the spiral walls are connected stepwise to the radial end walls at the lower ends of the inclined walls, the width of the annular space expands suddenly at those end wall portions.

Consequently, as the fluid rotates, the pressure near the end walls drops and the water drops adhering to nearby wall surfaces gather at the connection edges between the spiral walls and the end walls, then are blown off by the strong rotating flow whose speed has reached its maximum at those connection edge portions as previously noted and are blown against the inner wall of the outside casing.

Field of the Invention The present invention brings about the following particular effects.

Not only is a gas-wate#r separation effected by the action of a centrifugal force induced by fluid rotation, but also water drops are gathered positively at the connecting edges between the spiral walls and the end walls and the speed of the rotating flow is rendered maximum at those edge portions to blow off the water drops from these portions and cause them to be blown against the inner wall of the outside casing. As a result, the gaswater separation efficiency is extremely high.

It is not a matter of merely increasing the speed of the rotating flow, but the width of the annular space is rendered minimum at the lower end portions of the inclined walls to thereby render the speed of the rotating flow maximum at important points, namely, at the lower end portions of the inclined walls. Therefore, the rotating flow is relatively gentle before and behind those portions, thereby preventing the water drops from being carried to the outlet side together with gas or preventing the water surface at the drain valve portion from being disturbed and causing a malfunction of the drain valve.

Embodiment of the Invention If the following is taken into consideration in practising the present invention, better functioning and a better effect will be obtained.

If a longitudinal wall which projects radially from the outer peripheral wall of the partition wall member is formed upward from an upper end of each inclined wall, the fluid which enters the annular space while rotating strikes against the longitudinal wall, so the water drops partially strike against and adhere to the longitudinal wall and are thereby separated from the gas.

If at least an outer peripheral wall surface of the partition wall member which includes the inclined walls and the spiral walls is so formed as to have a rough skin like the skin of a pear, water drops will adhere to this outer peripheral wall surface more easily and the surface speed of the rotating flow in the vicinity of the wall surface is decelerated moderately, thus making it possible to catch water drops on the wall surface. The water drops thus caught on the wall surface are gathered at the connecting edge portions as previously described and blown against the inner wall of the outside casing. Thus, water drops can be separated from gas by adhering them to such a rough wall surface like a pear skin.

If the outer periphery of a lower end portion of the partition wall member is projected outward gradually downward to narrow the spacing from the inner surface of the casing, the rotating flow again increases its speed and separates water from gas and is again blown against the inner wall of the outside casing. In this case, a desired function and effect is obtained if the angle of inclination of the outer periphery of the lower end portion of the partition wall member relative to a vertical direction is set in the range of 25 to 50 degrees. Particularly, if such inclination angle is set at 35 degrees, the best results will be obtained.

The following description relates to an embodiment illustrated in the accompanying Figs. 1 to 4, which shows a concrete example of the above technical means.

Brief Description of the Drawings Fig. 1 is a sectional view of a gas-water separator according to the present invention combined with a reducing valve; Fig. 2 is a longitudinal sectional view of a partition wall member; Fig. 3 is a sectional view taken on line Ill-Ill of Fig. 2; and Fig. 4 is a perspective view of the partition wall member.

The embodiment of Fig. 1 is an integral combination of a gas-water separator A according to the present invention with a reducing valve B for vapor.

A casing comprises a spring case 2 which encloses a pressure setting spring 1 therein, a valve case 4 in which is disposed a pilot valve 3, a body 6 in which is disposed a main valve 5, a separator case body 8 which forms a gas-water separation chamber 7, and a bottom cover 9. These components are formed by casting.

A diaphragm 10 formed by a thin metallic plate is held between the spring case 2 and the valve case 4.

A lower end of the pressure setting spring 1 is in contact with an upper surface of the diaphragm 10 through a diaphragm disc 11, while an upper end of a cap 13 attached to a pilot valve stem 12 the pilot valve 3 is in contact with a lower surface of the diaphragm. The space above the diaphragm 10 is connected to the outside air through a passage 14, while the space therebelow is connected to a laterdescribed output 23 through a passage 15.

An adjusting screw 17 is attached to a ceiling wall of the spring case 2 through a stainless steel bearing 16 and is swivel-stopped with a lock nut 18. A steel ball 20 is disposed between the adjusting screw 17 and a spring shoe 19 disposed on an upper end of the pressure setting spring 1.

The portion of the adjusting screw 17 which projects to the exterior is covered with a protective cap 21 which isthreadedly connected to the spring case 2 removably.

The body 6 is formed with an inlet 22 and an outlet 23. The inlet 22 and the outlet 23 are separated through a horizontal wall 24 and are interconnected through a valve port 25 of a valve seat member which is threadedly connected to the wall 24. The main valve 5 is disposed below the valve port 25 while being held in a resiliently urged state by means of a coiled spring. Its upper end is connected to a piston 26.

The pilot valve 3 is positioned between a passage 27 leading to the inlet 22 and a passage 28 leading to a space formed above the piston 26. It comprises a pilot vaive stem 12 adapted to slide through a pilot valve seat 29 and a pilot valve element 30 connected to a lower end of the valve stem 12. And it is urged upward from below by means of a spring. In the passage 27 is disposed a screen 31.

The piston 26 is adapted to slide within a cylinder 32 which is attached to an inner periphery of the body 6, and two annular grooves are formed in an outer periphery of the piston, in which are disposed piston rings formed of polytetrafluoroethylene (PTFE) and springs inside the piston rings. The piston 26 is further provided with an orifice 33 which connects upper and lower surfaces of the piston to release therethrough a certain amount of fluid from the upper surface of the piston to thereby make a pressure control.

Around the main valve 5 of the reducing valve B is disposed a generally cylindrical double partition wall member 34. An outside cylinder is straight and it is formed lower than an inside cylinder which is gently divergent at upper and lower portions thereof. A tapered screen 35 is disposed outside the partition wall member 34. Inside the partition wall member 34 is integrally formed a connecting rod 36 on a central axis through a rib to guide a lower portion of the main valve 5. The inlet 22 is connected through the screen 35 to an annular space 37 which is formed between the two cylindrical portions of the partition wall member 34, while the inside of the partition wall member 34 is connected to the outlet 23 through the valve port 25 of the main valve 5.

In the annular space 37 are formed rotary vanes 38 integrally with the partition wall member 34. The partition wall member including the rotary vanes 38 is formed by casing according to a lost wax process and its wall surface is finished as to have a rough skin like the pear skin. Of course, there may be used another casting method or a cutting or another processing method, provided that at least the outer peripheral wall surface of the partition wall member is finished rough.

According to the lost wax process adopted in this embodiment, the surface roughness of the wall surface is 15 to um in terms of a maximum height Rmax according to JIS (B 0601). If the wall surface is finished rough so that the surface roughness is not less than 10 Rmax, there will be obtained a good separation effect. The wall surface to be finished rough like the pear skin is indicated by the reference mark C.

As shown on a larger scale in Figs. 2 to 4, the rotary vanes 38 are each composed of a longitudinal wall 39 which is projecting radially from an upper end of the inside cylinder of the partition wall member 34 to an upper end of the outside cylinder thereof, an inclined wall 40 which is inclined obliquely downward from a lower end of the longitudinal wall 39 in a position between the outside and inside cylindrical portions, and a spiral wall 41 formed at an upper surface of the inclined wall 40 spirally from the inside cylinder toward the outside cylinder. Five rotary vanes 38 are formed in the annular space 37. A terminal end of the spiral wall 41 is connected stepwise to a radial end wall 42.

A lower portion of the inside cylinder of the partition wall member 34 expands gradually downward and terminates in the vicinity of and at a predetermined spacing from the inner wall of the outside cylinder. Its angle 6 relative to a vertical direction is 35 degrees. If the inclination angle 6 is set in the range of 25 to 50 degrees, there will be obtained a good separation effect.

The lower cover 9 is attached with bolts to the lower end of the casing 8 of the gas-water separator A to form the drain valve chamber 7 in the interior and a spherical float 43 is disposed within the drain valve chamber 7.

In the lower cover 9, a drain valve seat 44 is attached to an inner end of a drain port 45. The float 43 is covered with a float cover 46 having a connection opening 47 formed in a lower portion thereof. The reference numeral 48 denotes a vent hole formed in an upper portion of the float cover 46.

Fluid which has entered from the inlet 22 is rotated by the inclined walls 40 of the rotary vanes 38. Water drops contained in the fluid are shaken out and separated outside by the action of a centrifugal force. The longitudinal walls 39 allow the inflowing fluid to drop perpendicularly and offset the rotating flow created by the inclined walls 40 to decrease the flowing velocity of the rotating flow and direct it more downward. At this time, the water drops partially strike against the longitudinal walls 39 and adhere to the surfaces thereof.

The spiral walls 41 serve to direct the rotating flow more outward than a tangential direction of the annular space 37. At the lower ends of the inclined walls 40 the width of the annular space 37 becomes minimum and the flowing velocity becomes maximum. Since the terminal ends of the spiral walls 41 are connected stepwise to the radial end walls 42, the width of the annular space 37 expands suddenly with the connection edge portions between the spiral walls 41 and the end walls 42 as a boundary. Consequently, as the fluid rotates, the areas near the end walls are reduced in pressure and the water drops adhered to the wall surface gather at the connection ridge portions.The thusgathered water drops are blown away from the connection edge portions by the strong rotating flow and blown against the inner wall of the casing 8 (also including the inner wall of the outside cylinder of the partition wall member 34).

The water drops thus separated flow down along the inner peripheral wall of the outside cylinder of the partition wall member 34 and that of the casing 8. The gas which has passed the lower end of the partition wall member 34 passes the inside thereof and moves toward the main valve 5 of the reducing valve B and flows out to the outlet 23, while the separated water enters the interior through the connection opening 47 of the float cover 46. At this time, the gas present in the interior of the float cover 46 gets out through the vent hole 48. The float 43 moves up and down according to water levels to open and close the drain valve port of the drain valve seat 44, allowing only water to be discharged to the exterior from the drain port 45.

Claims

1. A gas-water separator in which a cylindrical partition wall member is disposed in an upper portion within a casing to form an annular space between the partition wall member and a casing located outside the partition wall member; rotary vanes are disposed in the annular space; and upper and lower portions of the annular space and an inside bore of the partition wall member are connected to an inlet side, a drain valve portion and an outlet side, respectively, characterized in that said gas-water separator includes obliquely downwardly inclined walls and spiral walls each projecting outward gradually from an upper end of each said inclined wall toward a lower end thereof and connected stepwise to a radial end wall at the lower end of the inclined wall, said inclined walls and spiral walls being formed on an outer peripheral wall of said partition wall member.

2. A gas-water separator as set forth in claim 1, further including longitudinal walls projecting radially from the outer peripheral wall of said partition wall member, said longitudinal walls being formed upward from the upper ends of said inclined walls.

3. A gas-water separator as set forth in claim 1 or claim 2, wherein at least an outer peripheral wall surface of said partition wall member is so formed as to have a rough skin like a pear skin.

4. A gas-water separator as set forth in claim 1 or claim 2, wherein an outer periphery of a lower end portion of said partition wall member projects outward gradually downward to narrow the space from an inner surface of the casing so that an inclination angle of the outer periphery of said lower end portion relative to a vertical direction is within the range of 25 to 50 degrees.