CH476245A - Hollow float, in particular for a device for venting a container containing liquid and a gas under variable pressure - Google Patents

Description

Hollow float, in particular for a device for purging a container containing liquid and a gas under variable pressure The subject of the present invention is a hollow float, in particular for a device for purging a container containing liquid and a gas under variable pressure. variable, for example for a device for purging a separator or filter capable of being connected to a pressurized gas line.

The object of the present invention is to provide such a float, the construction of which eliminates the differential crushing pressure which would be applied to a hollow body subjected to high external pressure and which offers effective protection against unwanted intrusion. capacity of liquid in the float as well as a self-purging option to eliminate any liquid which may have accidentally entered it.

The float according to the present invention comprises at least one passage between its upper part and its lower part so that the pressure inside the float is always equal to the pressure outside said float.

The accompanying drawing illustrates, by way of example, a separator comprising a preferred embodiment of the object of the invention.

fig. 1 represents a section of a complete separator having an automatic device for draining the separated liquid and a float according to the present invention, the assembly having to be connected to a pressurized gas line; fig. 2 is a detail section, at a larger scale, of the float and certain Parts contained in FIG. 1; fig. 3 is a plan view of a pike of the separator containing the float according to FIG. 2; and fig. 4 is a plan view of another part of the separator containing the first float according to FIG. 2. The assembly represented in fig. 1 comprises the body of the separator 12 and a liquid container 14 connected by the thread 16, the sealing being effected by the gasket 18. The body 12 has an inlet nozzle 20 and an outlet nozzle 22 for connection ä a pressurized gas line.

The gas enters through the nozzle 20 and reaches the container 14 by passing through a flow guide 24 having vanes 26 giving the gas a helix rotational movement throwing the liquid and the solid impurities against the walls of the container. The liquid falls to the bottom of the container along with some of the solids.

The gas is forced to pass under the lower edge of the baffle 26 before reversing its movement, then it rises through the filter 30 and the Passage 32 to reach the outlet orifice 22. The filter 30 is very fine and serves practically to retain all solid particles not removed by centrifugal force. A conical screen 34 is disposed at an intermediate level in the container 14, its lower end being provided with a series of notches 36 to allow the passage of liquid and solid particles; it separates the container into a quiet area towards the bottom to prevent the gas from taking up the accumulated liquid, and into an upper area. A cylindrical screen 38 is mounted with gentle friction between the conical screen 34 and the bottom of the container to intercept solid particles large enough to interfere with the action of the servo-mechanism 40 and the float 42 housed completely in the cylindrical screen 38.

The servo-mechanism 40 (FIG. 2) has a bottom forming a valve, the base 44 determining the final wall 46. The base, as well as some other Parts will preferably be annular. The valve body also includes an inverted cup with cylindrical wall 48 and top flange 50. Base 44 and cup are made of a tough plastic material. The free lower edge of the cup has an internal annular groove 52 enclosing the outer edge of the base 44, as well as crenellations 54 to facilitate placement of the cup. The cup and its base form the chamber 56 in which the piston-shaped partition 58 is housed. This partition being able to be a flexible diaphragm with its edge fixed to the cylindrical wall 48, an has however preferred to give it the shape of a piston which can slide vertically in the chamber and dividing it into two compartments: the lower and the upper one, 60 and 62 respectively. The periphery of the piston Carries, for 1'obturation, an annular Borge 64 provided with a Seal 66. The base 44 has a hollow protuberance 68 descending vertically and Passing through an opening 70 made in the bottom wall of the container 14; this protrusion is secured in place by a threaded ring 72. The Link is made liquidtight by a sealing ring 74 housed in the Borge 76.

The bore 78 of the protuberance 68 serving as a drain tube for the accumulated liquid in the container 14 has a narrowing 80 forming a support shoulder for an annular joint 82 constituting a valve seat. The enlarged central portion of the partition 68 forms a hub 84 which has a stepped bore 86 into which is press fitted the upper end 88 of a stem 90 descending through the bore 78 and freely movable through the valve seat 82. A bulge 92 is formed at the underside of stem 90 and serves as a valve head, acting in conjunction with seat 82 to provide an outlet valve for liquid, either open or closed by movement of septum 68. .

Slots 54 primarily function as inlets for compressed liquid passing from the container into compartment 60. The liquid inlets are always open and the pressure in compartment 60 is always open. also exerts on the surface of the adjacent partition 58.

The upper flange 50 of the compartment 68 pos sMe a hollow mast, central and vertical, 94, preferably slightly conical. A tube 96 projects past the upper end of the mast a short distance terminating at the gas inlet port 98. The tube and the hollow intermediate portion of the mast serve as a pipe connecting the gas inlet orifice 98 to the compartment 62, the gas being able to enter this compartment 62 at the pressure prevailing in the pipe to balance, at the desired rate, the force. vertical exerted by the liquid in the compartment 60.

The float 42 carries a valve at its upper part, in other words a closure for the gas inlet port 98 in the form of a flexible diaphragm 100 fixed at its periphery in the recessed seat 102 of the yoke 104 of the float. Blocking panel 106 presses into seat housing 102. As the float rises it uncovers orifice 98, allowing pressurized gas to pass through tube 96 and mast to compartment 62. the float drops it closes the gas orifice.

To achieve the release of gas from compartment 62, rod 90 is provided with an axial purge channel 108 which is very narrow at its upper part 110 and partially closed off by a rod 112 which can be actuated and whose section is hardly weaker than that of Part 110, to leave only an extremely reduced annular Passage. The upper portion of stem 90 is formed into an annular valve seat 114, coaxial with the Constricted Passage 16. The cooperating valve element is formed by the face 116 of the lower end of the sleeve <B>118.</B> This sleeve will preferably be constituted by the Buna N 116 elastomer so as to stem 112, the upper end 120 of which reaches through tube 96 to a point just below orifice 98.

The sleeve 118, moving vertically, is carried by a guide comprising a cylindrical sleeve 122 and an annular flange 124 fixed in the first seat 126 of the upper flange 50. The flange 124 provides passages 128 for the flow of gas going from the orifice 98 to the compartment 62. The plan of this guide is given by FIG. 4. The downward movement of the sleeve 118 and the normal position of the seat 116 is limited by the contact of a shoulder 130 of the sleeve on the upper end of the sleeve 122. The sleeve is resiliently held in the position indicated by a bearing spring 132 surrounding the active rod 112 and a neck 134 at the upper end of the sleeve which bears against the bottom 136 at the bottom of the cavity 138 of the mast 94. The sleeve can be moved with rod 112 to manually open orifice 98; it springs back into place under the action of the spring 132. When the sleeve is in its rest position, the seat 116 is positioned in such a way that it will be contacted by the seat 114 shortly after the valve head 92 has engaged in the seat. valve seat 82 as indicated by dotted lines in FIG. 2.

It is good that an elastic force constantly acts in the opening direction of the valve 92 for liquid outlet. This is achieved by the aid of a compression spring 140 placed between the upper face of the partition 58 and the upper flange 50 of the compartment 62 and acting through the partition, it pushes the valve 92 downwards, in open position. The effective pressure area of partition 58 is greater in compartment 62 than in compartment 60.

To prevent partition 58 from pressing flat on end face 46 blocking the exit of liquid, a multi-purpose retainer has been provided. This retainer (Figs. 2 and 3) includes a thin retaining ring 142 pressed into the upper portion of the bore 78 to hold the valve seat 82 in place, and surmounted by a flange. integral 144 in the Periphery of which radial passages 146 have been cut at intervals. In addition, to hold the valve seat in place, the retainer includes a stopper for the bulkhead 58; passages 146 provide fluid flow through compartment 60 to passage 78.

When the device is at rest and the pressure in the line is near or equal to atmospheric pressure, the various parts of the mechanism rest in the positions indicated.

Valve 92 and liquid outlet 78 are open while gas inlet 98 is closed by diaphragm 100. the fluid enters through the inlet 54 and exits through the outlet. But since the latter is throttled, the pressure rises in the compartment 60 overcoming the effect of the spring 140 and the difference in the effective areas on the two sides of the partition, causing the partition to rise to the position marked by the dashed line. (fig. 2). As a very small amount of gas at atmospheric pressure flows through Passage<B>110</B> During this short time, nearly all of the gas in compartment 62 is substantially compressed and retained by the closure of the valve. formed by 114 and <B>116.</B> At this time the valve 92 is closed by the displacement of the partition and the container is closed.

When the device starts from rest and the pressure rises in the container 14, or when the pressure increases in the bowl as a result of normal operation, or during spillage, if there is too much purge from the compartment 62, the pressure of the gas enclosed in this compartment 62 added to the force of the spring 140 may not be sufficient to equalize the pressure in the chamber 60. In these circumstances the partition will be forced beyond the position shown by the broken line and Valve seat 114 will cause sleeve 118 to move upward. The valve head 92 does not prevent this action, because the valve seat 82 is such that its contact edge deflects upwards. Sleeve 118 is raised enough by movement of septum 58 to bring upper end 120 of stem 112 into contact with diaphragm 100 and lift it above orifice 98. This allows the compressed gas to escape. enter the orifice and enter the chamber 62 until the forces are balanced, then the septum 59 will fall back into place and the diaphragm 100 will close the orifice 98.

During the operation the liquid separates from the compressed gas and collects at the lower part of the container 14. When the liquid reaches a level 150 near completion (fig. 2) the float has risen, - phase above the gas inlet orifice 98, and the gas passes through the tube 96 and the cavity 138 to reach the compartment 62. When the unit pressure of this compartment increases to a value approaching - or substantially equal - the pressure in the line, the total pressure of the gas acting downwards, added to the force of the spring 140 exceeds the resisting force of the liquid in the compartment 60 and the valve 92 opens to drain the gas. liquid from the container.

The Trangle Passage 110 is open as long as the bulkhead is in the Valve Open Position; gas is constantly flowing out of compartment 62. However, gas inlet 98 and cavity 138 are significantly larger than the Restricted Passage 110 and therefore some gas reaches the compartment to replace the constricted one. who escaped. As the float descends, the orifice 98 is closed, shutting off the supply of supplemental gas, while the throttled charge continues. Consequently, the gas supply to compartment 62 is gradually reduced RTI ID="0003.0275" WI="15" HE="4" LX="171" LY="2037"> and the partition 58 moves well towards 1st up, closing the 1st Strang16 Passage and the exit of the liquid, the 1st drainage cycle being closed. The Pressure of the gas remaining enclosed in the compartment 62 adds its Pressure to the force of the spring 140 and balances the forces prevailing in the compartment 60. The balance of forces is sought and obtained and if it is necessary to achieve it, Following the Balance, an additional gas will automatically be obtained by moving the bulkhead beyond the Position marked by the dashed line, as described above, to re-establish the Gas Pressure after discharge. If the float then rises and opens inlet port 98 a sufficient increase in gas entering compartment 62 will cause the pressure there to rise with the result that the charge valve opens again. Since the mechanism is in such a precarious balance, the valve is very sensitive to variations in liquid level and opens frequently for small, gently executed loads which do not disturb the pressurized gas line.

The balance takes into account the liquid pressure on valve 92. The effective area of the valve is very small compared to that of the bulkhead and the opening force exerted by the valve is only two percent of that of the valve. undergone by the partition under the effect of the compressed fluid.

Since the compartment 62 retains the gas at a pressure slightly less than that exerted in the pipe, the forces developed by the fluid on the various parts of the servo-mechanism are weak enough to be able to be neglected, so that said parts can small and as light as possible, without risking errors, under normal operating conditions.

The presence of the active rod 112 in the narrow passage 110 effectively avoids any blockage by solid particles which could have accidentally penetrated into the compartment 62. As this passage is annular instead of circular, it is impossible to finely particles to block the entire surface available for the 1st flow. In addition, the Restricted Passageway moves axially relative to the stem throughout the drainage cycle and this movement makes it self-cleaning.

Maintaining the gas pressure in compartment 62 only slightly below that in the vessel or line, the difference being from 210 to 350 g/cm2, reduces the required buoyancy of the RTI ID="0003.0549 " WI="12"HE="4" LX="1461" LY="1319"> float to open gas inlet valve. The vertical forces on all parts of the float and valve except the small portion above port 98 are exactly in balance, all ports being subject to the pressure in the line. . If the gas in compartment 62 were at atmospheric pressure, as in the previous devices, the differential pressure at the top of the center of the yoke or diaphragm 100 would be equal to the unit pressure in the line multiplied by the surface area of the yoke. the orifice 98 including the face of the end of the tube 96. At low pressures of 0.35 to 0.70 kg/cm2 the matter is not serious. However, at high Pressures, say at 70 kg/cm2, an orifice area as small as 0.08 cm2 would require a force from the float of about 60 g or more, the force required being directly proportional to the Pressure. The necessary size of the float completely eliminates the possibility of constructing a small and compact device, usable in high pressure pipes.

Currently the differential pressure at the gas inlet port 98 can be made as low as possible, about 210 to 350 g/cm 2 , and varies only slightly with fluctuations in gas pressure in the line. Therefore, at any operating pressure, a float with a low buoyancy force, for example between 3 and 30 grams, can be used, the area of the orifice 6 being 0.08 cm2. . Thus the pressure in the second compartment 62 is automatically maintained at a predetermined value below that prevailing in the container 14 without taking into account the high or low value of the regime pressure of the gas in said container, in other words terms the validity is the same at all Working Pressures.

The construction of the diaphragm 100 also reduces the lifting force required. The diaphragm is in the form of a disc made of a flexible material and of aesthetic presence such as, for example, Buna<B>N.</B> As seen in fig. 2 in its rest position, its central portion 152 rests on the inlet port 98, and its body has a slightly conical shape because of its flexibility and the weight of the float 42. As the float rises The body assumes an inverse conical shape with the rim higher than the central portion 152 still held down by the differential pressure. The upwardly acting force of the float is now applied to the outermost edge of the center portion, due to the flexibility of the material and material, and need only exceed a small fraction of the total differential force. The central part is thus gradually removed from the mouth of the inlet port using only a minimum of force.

The construction of the float 42 eliminates the differential crushing pressure which would be applied to a closed hollow body under the high pressure prevailing in the pipeline; it effectively protects against the unwanted intrusion of liquid and has a self-purging action eliminating any that may have entered accidentally. The float is constituted by two Elements the cup 164 and the yoke 104. The yoke is provided with at least one passage 156 allowing the compressed gas to penetrate freely under the first diaphragm 100. The yoke 104 has an outer descending annular border 158 and a appendix descending, cylindrical, 160, arranged coaxially, the internal surface of which is provided with a certain number of longitudinal ribs 162 distributed over the first periphery.

The cup 164 has a downward-pointing frustoconical bottom 154 and a vertically rising outer cylindrical wall 166, as well as a vertical inner cylinder 168. The wall 166 has at its upper part an internal groove 170 intended to cover the Rod of the Annular border 158 to make Joint. The inner surface of the wall 168 is provided with numerous longitudinal ribs 172 tapering towards the center and upwards and distributed around the circumference. They allow the liquid and the gas to circulate between the float and the hollow central mast 94, guiding the float in its vertical movement, ensuring sufficient lateral clearance which does not interfere with the control of the inlet orifice 98 because Any portion of the central part of the diaphragm 100 ensures its leaktight closure.

The ribs 162 gently rub against the outer surface of the wall 168 thus terminating a number of pathways for flow from the RTI ID="0004.0275" WI="12" HE="4" LX ="896" LY="2056"> top of wall 168 to bottom of wall 160 just above the junction of walls 168 and 164 where a shallow annular passageway leads to the interior of the float . Close to its upper end the wall 160 is provided with an inwardly extending lip 174 which serves to protect the inlet leading to the interior of the float.

In operation, when the compressed gas enters the container, it enters its interior through the passages between the walls 160 and 168, equalizing the pressures on said walls. Since this inlet is well above the level of the fluid, the admitted gas has no tendency to entrain liquid. If any liquid entered the float, it would remain in the reservoir at the junction of walls 164 and 168, at the other end of the annular inlet, where it will remain until the end of the operation. When the line ceases to operate and the pressure is removed, the compressed gas contained in the float will escape through the annular passage pushing the liquid past it and back into the vessel. Normally only a few drops are involved and the float is ready for a new operation. Thanks to this self-purging action the float will never get soaked with water.

It may be necessary to drain the liquid manually, by pushing rod 112 upwards, which can be reached through the release orifice. The upper portion 120 of the stem driving the diaphragm 100 raises it to open the gas inlet port 98; Gas entering compartment 62 operates the mechanism. As soon as this operation is started, the rod can be released. As rod 112 is linked to sleeve 118, the latter presses spring 132 upwards during the opening action, but as soon as rod 112 is released it springs back into place at the same time as the sleeve. .

If the pressure in the line drops substantially or if it is shut off completely, the pressure drops in the compartment 60 and the mechanism will open the valve and expel the liquid. If the pressure is reduced, that of compartment 62 will slowly decrease once seats 114 and 116 are cleared, until a new equilibrium condition is reached, and the mechanism will operate as before. .

If the drain valve has a tendency to äRTI ID="0004.0551" WI="9" HE="4" LX="1786" LY="1297"> stick in the open position, it may leak all the liquid and let it escape. gas under pressure. However, with the present construction this is practically impossible, because if the compartment 62 empties to atmospheric pressure the force acting upwards on the partition will be sufficient to release the valve and close it.

When the mechanism is designed for a given operating pressure it can be constructed to operate without the use of the spring 140. the stem 90 above the bulge 92. The forces exerted by the pressure of the fluid can be balanced in such a way that the weight of the partition, the stem and the valve give an imbalance causing said valve to open, since the device is normally used in the upright position shown in the drawing. If desired, additional weights to add to the tail can be determined.

When all the valves are closed the balance of forces is maintained. As soon as the rising float causes the gas inlet valve to open, the resulting increase in pressure in the second compartment, due to the additional gas admitted, destroys the balance and the relief valve begins. to open and drain the liquid. There are several variables which intervene automatically to perfect the balance of forces, variables increasing in value when driving starts from rest, when the pressure in the container or in the bowl varies during operation or when 'During the discharging or emptying of the liquid there is excessive leakage of gas from the second compartment.

The differential pressure at the gas inlet orifice multiplied by the area of that orifice determines the force the float must exert to operate the valve. Even if the orifice is very small, if it is the atmospheric pressure which reigns there, as is the case for the above-mentioned devices, the force necessary to open it for a pressure in the pipe of 7 kg/ cm2 or more, eventually reaching several kilograms. This requires a large float and renders all efforts to achieve a compact device useless.

However, the design which allows the pressure difference to be maintained between 210 and 350 g/cm2, regardless of the pressure in the line, now only requires a gram-magnitude fordre force to make the opening.

Claims (4)

CLAIM Errous float, in particular for a device for draining a container containing liquid and a gas under variable pressure, characterized in that it comprises at least one passage between its upper part (104) and its lower part (164) so that the pressure inside the float (42) is always equal to the pressure outside said float. 1. Float according to claim, characterized in that its lower part (164) is cup-shaped and has at least one rising cylindrical wall (168), while its upper part (104) is clevis-shaped. and has at least one downward cylindrical wall (160), the latter wall surrounding, at a distance, said wall of the first part. 2. Float according to sub-claim 1, characterized in that said cylindrical wall (168) of the lower part (164) comprises longitudinal ribs (162) which contact said cylindrical wall (160) of the upper part (104). 3. Float according to sub-claim 1, characterized in that the lower part (164) has a bottom (154) of frustoconical shape. 4. Float according to sub-claims 1 and 3, characterized in that said cylindrical wall (160) of the upper part (104) extends practically to the lowest part of the bottom ( 154) from the lower part (164).