DK177019B1 - A pressure relief valve - Google Patents

Abstract

Pressure equalization valve with a flow pipe, where the height of the flow pipe is equal to or greater than the third width of the flow pipe.

Description

DK 177019 B1 i

Field of Invention Pressure Relief Valve

The present invention relates to a pressure equalization valve for pressure equalization 5 between a closed space and the ambient atmosphere. More specifically, the invention relates to the field of high speed pressure relief valves.

Such pressure relief valves are particularly used as pressure relief means in arrangements where, for example, a cargo or stationary warehouse emits gases at a variable rate. Such an arrangement may include flammable carbohydrate tanks, especially during filling such tanks, chemical loads, asphalt loads or solids, such as fruits which, over time, emit gases upon storage.

15 Valves of this type are usually combined with vacuum valves in pressure vacuum high speed valves. The performance of such valves is subject to requirements and international regulations specified in, for example, IMO MSC / Circ 677 from the

International Maritime Organization and European Standard EN 12874. '' j 20

BACKGROUND OF THE INVENTION

A common problem with pressure relief valves used in arrangements where gas is emitted from a substance confined in a closed space 25 at a constant or variable rate is a phenomenon called hammering or oscillation.

Pressure relief valves are designed to open at a specific pressure that can build up in the closed space and to close when the pressure returns to a certain lower pressure. In such systems, the valve often tends to open and close very quickly - hammering. Hammering / osciflation occurs due to an imbalance caused by a pressure loss in the valve and the pipe system downstream of the valve, so that the valve, under certain operating conditions, moves between its extreme positions (open / closed) at a frequency substantially above 0.5 Hz. This movement causes severe shocks between the valve element and the valve seat (in closed position DK 177019 B1 2) and between the valve element and the valve top (in the open position), which over time we! destroy the parts involved. Hammering is thus particularly undesirable because parts of the valves will be subject to increasing wear, which results in a need for continuous maintenance and / or replacement of valves or valve parts.

Hammering also causes the gas flow rate from the valve between the valve seat and the valve element to decrease, thereby reducing or eliminating a desired flame retardant property of such valves.

The above provisions further require that the hammering phenomenon must be eliminated or reduced in order to preserve the aforementioned flame retardant characteristics of the valves.

Pressure relief valves are known in the art. An example of such a valve is shown in WO 02/095275 A1. This valve has magnetic means for securing a specific opening pressure for the valve and a lifting plate to assist in lifting the valve member. Since the area of the lifting plate must be larger than the outflow opening defined by the valve seat to ensure flow dynamics, this valve's valve body has a complicated geometric structure. Due to the flow dynamics around the lifting plate, hammering is only limited but not fully reduced. Furthermore, the design of this valve is complex, which results in high production and maintenance costs and makes it difficult to maintain.

Furthermore, the geometry of the type of valve presents problems with respect to the gap between the lift plate and the wall of the valve body. There is a limited gap between the lift plate and the valve body wall, making these types of valves unsuitable for sticky, crystallizing and frozen load types. In the prior art this is partially compensated for by the bell shape of the valve body which in turn causes problems with flow dynamics.

30

An improved pressure relief valve will therefore be advantageous, especially a more efficient and / or reliable pressure relief valve.

DK 177019 B1 3

Objects of the Invention

It is an object of the invention to provide a pressure relief valve! for pressure equalization between an enclosed space and the ambient atmosphere, thereby eliminating hammering / oscillation characteristics.

5

It is a further object of the present invention to provide an extended life pressure relief valve and reduced maintenance time and reduced maintenance costs.

It is a further object of the present invention to provide a pressure relief valve of a simplified design which is easy and cost effective to manufacture, maintain and repair.

It is a further object of the present invention to provide an alternative to pressure equalization valves of the prior art for pressure equalization between a closed space and the ambient atmosphere.

In particular, it can be considered an object of the present invention to provide a pressure relief valve that solves the above-mentioned problems in the prior art.

Brief Description of the Invention

It is intended that the above-described object and several other objects be achieved in a first aspect of the invention by providing a pressure equalizing valve comprising an elongated valve housing having an inlet end which can be connected to a closed space, an outlet end disposed therein. opposite the inlet end of the housing, 30 o a longitudinal center axis and o a substantially uniform first interior width perpendicular to the center axis in a cross section along the center axis from the inlet end to the outlet end, a valve seat disposed at the outlet end, having a second internal width perpendicular to the central axis in cross-section along the central axis; a valve member arranged to cooperate with the valve seat and arranged for translational movement in a direction along the axis to provide opening and closing of the valve; providing a resistance to opening the valve, • a flow tube disposed between the the outlet end and outlet end having a third outside width perpendicular to the center axis of a cross-section along the center axis, and a height defined between a first end facing the inlet end and a second end facing the outlet end; and • a connection between the valve element and the flow tube, whereby the flow tube and the element are arranged for simultaneous translational movement along the axis 15 where the height of the flow tube is equal to or greater than the third width of the flow tube.

The objects of the invention are further achieved with embodiments described in the various dependent claims.

20 Brief Description of the Drawing

The pressure relief valve according to the invention will now be described in more detail with reference to the accompanying figures. The figures show ways of implementing the present invention and are not to be construed as limiting other possible embodiments within the scope of the attached set of claims. 1 shows a partial sectional view of a pressure vacuum high speed valve with a pressure equalizing valve according to an embodiment of the invention.

FIG. 2 is a sectional view showing details of a pressure relief valve according to an embodiment of the invention.

FIG. 3 shows a system comprising a closed space in the form of a tank, and 35 shows various applications of a pressure relief valve; and DK 177019 B1 5. 4 shows the behavioral characteristics of a pressure relief valve according to one embodiment of the invention in a test study.

Embodiments of the Invention Figure 1 shows a pressure vacuum high speed valve 100. The right side of the figure shows a pressure equalization valve 1 according to an embodiment of the invention. The left side of the drawing comprises a vacuum portion of this valve 100 and does not form part of the invention.

It should be emphasized that the pressure equalizing valve 1 according to the invention can be used in combination with such a vacuum valve or can constitute a separate unit.

The pressure equalizing valve 1 comprises a housing 10 with a valve seat 20 and a valve element 30 arranged for translational movement along a central longitudinal axis A of the valve housing 10 between a closed position where the valve element 30 abuts the valve seat and an open position where the valve element 30 moves away. from the valve seat 20 to provide an outflow opening to a gas flowing 20 through the valve body. The valve housing 10 has a first inlet end 11 suitable for mounting to a closed compartment 1a, such as a tank, or to pipe 1b connected to such a closed compartment as shown in FIG. 3. The valve housing 10 further has an outlet end 12 arranged diametrically adjacent the inlet end 11 along the axis A of the housing 10. The valve seat 20 is arranged on the outlet end 12.

The pressure equalizing valve 1 is intended to be mounted with the outlet end 12 facing upwards and the inlet end 11 facing downward with respect to gravity such that the central longitudinal axis is located upright or vertically.

30

The valve housing 10 has a substantially uniform internal width wl in a direction perpendicular to the elongate axis from the inlet end 11 to the outlet end 12 seen in any section through the valve housing 10 through the center axis A.

The housing 10 preferably forms a cylindrical interior space 16 such that w1 is a diameter of a circular cross section of the space 16 perpendicular to the central longitudinal axis A. However, the interior space 16 may have a different cross-sectional shape, e.g. octagonal or other polygonal shapes.

By substantially uniform width is meant that the width may vary due to 5 production tolerances and also that pipe inlets or outlets, windows 17, etc. may be provided in the interior wall defining the interior space 16.

The valve seat 20 forming the outlet of the valve 1 has a width w2 in a section including the central longitudinal axis A and in a direction perpendicular thereto.

The valve seat 20 is preferably circular; the width w2 being a diameter. The width w2 of the valve seat 20 is preferably the same or only slightly smaller than the width w1 of the interior space 16 of the housing 10.

A valve member 30 is arranged to cooperate with the valve seat 20 in the closed position of the valve 15. The valve member 30 is located on the outside of the interior space 16, and is arranged for translation movement along the center axis A, between a closed position (see Figs. 1 and 2) where a portion of the lower side of the valve member 30 interacts with valve seat 20, and an open position. (not shown) where the valve member 30 is moved away from the valve seat 20 to form a 20 outlet opening through which a gas can escape.

The valve member may be mounted on a shaft 61 formed along the axis A of the housing, the shaft 60 being slidably disposed relative to holding means 18, 19 formed relative to the valve seat 20 and / or the housing 10. A stop device 65 is formed on the shaft 61 to the valve member 30 to restrict the opening of the valve 1, for example, by the stop device adjacent to the holding member 19 or by other suitable means provided in the housing 10.

A flow tube 50 is provided on the shaft 61, the flow tube being disposed in the interior space 16. The shaft 61 thus forms a connection 60 between the valve member 30 and the flow tube 50. This connection is fixed so that the flow tube, the connection 60 (in this embodiment). shaft 61) and valve member 30 are displaceably disposed as a single unit or assembly, although for manufacturing purposes they may be formed as individual parts 35 connected during manufacture.

DK 177019 B1 7

Other means of providing and guiding the translational movement of the valve member 30 may be arranged, for example, by means of guide rails outside the interior space 16. The connection 60 between the flow tube 50 and the valve member 30 may also be separated (not shown).

5

The flow tube 50 is disposed between the inlet end 11 and the outlet end 12. It has a third outer width w3 which is perpendicular to the center axis A in a cross section along the center axis A, and a height h defined between a first end 51 facing the inlet end 11 and a second end 52 facing 10 outlet end 12.

The flow tube 50 has

Means 40 for providing a resistance to opening the valve are provided between the housing 10 and the assembly consisting of the valve member 30, the connection 60 and the flow tube 50.

Such a member 40 may be provided in the valve member 30 in the form of a magnet or magnetizable body disposed to cooperate with a magnet or a magnetizable body formed in or connected to the housing 10. The pair forms a means for providing a downward (relative to the intended use) abutment force Fc containing contributions from the mass of the valve member 30, the mass of the connection 60, either the mass of the magnet or the magnetizable body, depending on which of these parts is mounted on the connection 60 / the valve member 30, and from the attracting force Fm between the magnet and the magnetizable body. Thus, the connecting force Fc is to be understood as the force holding the pressure valve closed, ie. the closing force of the pressure valve.

The magnetizable body is configured to cooperate with the magnet in the closed state of the pressure valve 1. It is preferred that the magnet and magnetizable body be located in the region at the outlet end 11 when regular access to the magnet is needed.

DK 177019 B1 8

Alternatively, however, the magnet and magnetizable body may be mounted in conjunction with the connection 60 at the end located in the interior space 16 away from / opposite the valve member 30, below the flow tube 50.

It can be either a permanent magnet or, for example, an electromagnet.

5

If the pressure rises above atmospheric pressure in the closed space, such pressure due to the gap between the flow tube and the inner wall of the housing 10 will also prevail in the space between the flow tube 50 and the valve element 30. The pressure in this space is thus equal to the pressure in the closed space. (tank) and the pressure affects the top surface and bottom surface of the flow tube 50 with the same force. As long as the superatmospheric pressure does not produce an upward force on the valve member 30 exceeding the closing force Fc of the pressure valve, the pressure valve will remain in the closed state. The upward force on the valve member 30 can be determined as the superatmospheric pressure in the vessel multiplied by the opening area 15 defined by the valve seat 20.

When the superatmospheric pressure exceeds the closing force of the pressure relief valve Fc, the pressure relief valve opens. The gas outflow causes the pressure on the surface of the flow pipe 50 facing the outlet end 12 to decrease.

The upward movement of the valve member 30 towards the fully open position of the pressure relief valve 1 is then controlled to a certain extent by the force exerted by the gas flow on the bottom surface of the flow tube 50 and the gas passing over the outer side wall of the flow tube. The first impact can be determined as the superatmospheric pressure of the container multiplied by the area defined by the cross-sectional area of the flow tube. The lifting force of the gas on the flow tube increases, and the velocity of flow of the flow tube 50 and thus the valve element 30 increases in a direction towards the fully open state of the pressure valve, thus helping to keep the valve element 30 "liquid".

The valve member 30 is held in the open position by the gas flow. The downward force on the valve member 30 contains contributions from the mass of the valve member 30, the mass of the connection 60, either the mass of the magnet or the magnetizable body, depending on which of the two parts is mounted on the connection 60 / the valve member 30. The force of attraction Fm between the magnet and DK 177019 B1 9 the magnetizable body does not contribute substantially as soon as the valve member 30 has moved slightly away from the position shown in Figs. 1 and 2.

Experiments have shown that if the height h of the flow tube 50 is equal to or greater than the third width w3 of the flow tube 50, the flow tube will cause the valve member 30 to "flow" into the gas flow, avoiding the phenomenon of hammering / oscillation.

The third width w3 of the flow tube 50 is preferably smaller than the second width w2 of the valve seat 20 which opens in such a way that the cross sectional area of the flow tube is less than the cross sectional area of the opening of the valve seat 20. The flow pipe is thus easily mounted in the housing 10 during manufacture and also in connection with maintenance and / or repair.

The third width w3 of the flow tube 50 is preferably between 60% and 90% of the first internal width w1 of the valve housing 10, thereby providing a sufficient space between the flow tube and the interior wall of the housing 10.

In a first preferred embodiment, the third width w3 of the flow tube 50 is 80% of the first internal width w1 of the valve body 10.

20

As can be seen in the figures, the flow tube 50 has a uniform width w3 from the first end 51 facing the inlet end 11 and the second end 52 facing the outlet end 12.

The valve member 30 is preferably shaped such that it can intercept a gas flow through the valve 1 as it flows past the valve seat 20. This can be achieved by forming the valve member drop-shaped or cone-shaped (Figs. 1 and 2). Thus, a vertical flow of the effluent gas can be obtained.

A pressure relief valve (1) according to any one of claims 1-8, wherein the first inner width (wl) of the valve housing (10) is 100 mm, the third width (w3) of the flow tube (50) is 80 mm in diameter and the second width ( w2) of the opening of the valve seat (20) is 90 mm.

DK 177019 B1 10

As shown in the figure, the flow tube 50 may be hollow. In FIG. 1 and 2, this is provided by a cavity at the bottom of the flow tube but may also be provided by an upwardly extending cavity or a closed cavity in flow tube 50. In a hollow flow tube, the mass of the flow tube can be adjusted to provide optimal operation of the valve 1. The foregoing provisions limit the materials which may be used for the parts of such a valve. The hollow flow tube thus allows a certain height h of the flow tube to be obtained without necessarily having too much mass.

10 The flow tube may be made of stainless steel.

The distance d between the contact surface 31 between the valve member 30 and the valve seat 20 and the other end 52 of the flow tube 50 is arranged so that the second end 52 of the flow tube 50 at the open state of the valve 1 is at least 15 mm, such as between 25-30 mm.

In one embodiment, the inner diameter of the housing 10 is 100 mm, the diameter of the flow tube 50 is 80 mm, and the opening of the valve seat is 90 mm. The mass of the assembly consisting of the flow tube and the valve element can be 4.3 kg, 4.6 kg or 4.7 kg.

20

The latter embodiment has been tested and has been shown to eliminate the phenomenon of hammering. The test result is illustrated in FIG. 4th

Although the present invention has been described in connection with the 25 embodiments specified, it should not be construed as in any way limited to the examples given. The scope of the present invention is defined in the accompanying set of claims. Within the context of the claims, the terms "comprehensive" or "include" do not exclude other possible elements or steps.

Also, such references, such as "one" or "one", etc., should not be interpreted as excluding a plural form. Also, the use of reference characters in the claims in relation to elements set forth in the figures is not to be construed as limiting the scope of the invention. Furthermore, individual characteristics mentioned in different claims may advantageously be combined and the fact that these characteristics are mentioned in different claims does not preclude a combination of characteristics not being possible and advantageous.

Claims (11)

1. Pressure equalizing valve (1) comprising • an elongated valve housing (10) having an inlet end (11) connectable to a closed compartment, 5. an outlet end (12) disposed opposite the inlet end (11) of the housing (10) o, a longitudinal center axis (A) and o a substantially uniform first inner width (w1) perpendicular to the center axis (A) in a cross section along the center axis (A) from the inlet end (11) to the outlet end (12); valve seat (20) disposed at the outlet end (12) having a second inner width (w2) perpendicular to the center axis (A) in cross-section along the center axis (A), a valve member (30) arranged to cooperate with valve seat (20) 15 and arranged for translational movement in a direction along axis (A) to provide opening and closing of valve (1), means (40) to provide resistance to opening of valve (1), flow tube (50) disposed between the inlet end (11) and 20 outlet end (12), and so m has a third outer width (w3) perpendicular to the center axis (A) in a cross-section along the center axis (A), and a height (h) defined between a first end (51) facing the inlet end (11) and a second end (52) facing outlet port (12); and 25. a connection (60) between the valve element (30) and the flow tube (50), whereby the flow tube and element are arranged for simultaneous translational movement along the axis (A) where the height (h) of the flow tube (50) is equal to or greater than that of the flow tube ( 50) third width (w3). 30 A pressure relief valve (1) according to claim 1, wherein the third width (w3) of the flow tube (50) is less than or equal to the second width (w2) of the valve seat (20). DK 177019 B1 12 A pressure relief valve (1) according to claim 1 or 2, wherein the third width (w3) of the flow tube (50) is between 60% and 90% of the first interior width (wl) of the valve body (10). A pressure relief valve (1) according to claim 3, wherein the third width (w3) of the flow tube (50) is 80% of the first interior width (wl) of the valve body (10). A pressure relief valve (1) according to any one of claims 1-4, wherein the flow tube (50) has a uniform width (w3) from the first end (51) facing 10 to the inlet end (11) and the second end ( 52) facing the outlet end (12). A pressure relief valve (1) according to any one of claims 1-5, wherein the housing (10) has a cylindrical inner surface (14) and the flow tube (50) has a cylindrical outer surface (54), the widths ( w1, w2, w3) are diameters. A pressure relief valve (1) according to any one of claims 1-6, wherein the valve member (30) is formed to intercept a gas flow through the valve (1) as it flows past the valve seat (20). 20 A pressure relief valve (1) according to claim 7, wherein the valve member (30) is conically shaped. A pressure relief valve (1) according to any one of claims 1-8, wherein the first inner width (wl) of the valve housing (10) is 100 mm, the third width (w3) of the flow tube (50) and the second the width (w2) of the opening of the valve seat (20) is 90 mm. A pressure relief valve (1) according to any one of claims 1-9, wherein the flow tube is hollow. A pressure relief valve (1) according to any one of claims 1-10, wherein the flow tube is formed of stainless steel.