NL2006998C2

NL2006998C2 - A pulse valve system having a pipe holder with axially deformable spring arms.

Info

Publication number: NL2006998C2
Application number: NL2006998A
Authority: NL
Inventors: Stefanus Theodorus Maria Schijndel
Original assignee: Asco Controls Bv
Priority date: 2011-06-24
Filing date: 2011-06-24
Publication date: 2013-01-02
Also published as: EP2723469A1; WO2012177130A1

Description

P30720NL00/RR

Title: A pulse valve system having a pipe holder with axially deformable spring arms.

The invention relates to the field of pulse valve systems which are used to controllably blow out pulses of compressed gas.

Such pulse valve systems are known to be used in combination with dust collector systems or pollution preventing filter installations in order to periodically blow air into them in 5 a direction opposite to a filtering direction so as to detach adhered dusts from the filtering surface. In the beginning stand alone pulse valves were used for this which all had a die cast body having a machined seat for a diaphragm of the valve to lie sealingly against in a closed position of the valve. See for example EP-0 817 931.

When the dust collector systems and pollution preventing filter installations grew 10 bigger, this evolved to pulse valve systems having a large common pressurized gas storage tank against the outside of which large numbers of controllable pulse valves can be mounted. With this the large common pressurized tank no longer was welded steel but was formed as an extruded aluminium body having an interior space. After having extruded the aluminium body, for each pulse valve a main opening was machined into the tank wall. With 15 this each main opening was machined in such a way that it comprised a central inlet opening and four banana shaped slots around it. At the outer side around each central inlet opening seats were formed for diaphragms of the pulse valves to lie sealingly against in closed positions of their valves. At the inner side around each central inlet opening seats were formed for so-called blow pipes to be placed sealingly against with their inlet ends. At 20 positions diametrically opposite the main openings, blow pipe openings were also machined into the tank wall. During assembly the blow pipes can be inserted into the tank through the blow pipe openings. As soon as the inlet ends of the blow pipes have come to lie sealingly against their respective seats of the main openings, the opposite outlet ends can be fixedly mounted to mounting flanges of the blow pipe openings by means of suitable pipe holders. 25 For this the pipe holders have sleeve shaped parts sealingly fitting around the outlet ends of the blow pipes, while supporting and delimiting them in the axial direction. They can also be connected threaded to each other.

However, the machining of the steering and blow pipe openings required huge investments in production machines. In case of a small mistake, broken tool or damaging of 30 one of the openings, the complete tank was immediately useless.

It has been tried to overcome this disadvantage by starting to make the main openings as simple round openings. The blow pipes then were only fixedly mounted with their outlet ends to the blow pipe openings of the tank wall. The inlet ends of the blow pipes -2- then were no longer supported but just kept supported floating in front of the steering valve. See for example US 6,354,562.

This however made the blow pipes instable, particularly because of the high pressure air blows which had to flow through them during operation.

5 In order to prevent this, a wide variety of rigid pipe holders have then been developed which could be placed between the main openings and inlet ends of the blow pipes. Each of these pipe holders have a part sealingly connecting to an inlet end of a blow pipe, and have radially outwardly projecting support arms which are well able to support the inlet end of the blow pipe interspaced from the tank wall and main opening therein. The 10 support arms are thus able to delimit a flow path for the supply of compressed gas to flow out of the tank into the blow pipe in the open position of the valve. The ring shaped parts of those pipe holders then comprise the seat for a diaphragm of the valve to sealingly lie against in the closed position of the valve for then closing the flow path. Thus the pipe holders still made it possible to machine rather simple round openings as main openings into 15 the tank wall. EP-1 094 880 and US-7,837,062 show two variants of such rigid pipe holders.

The disadvantage of these known constructions however is that the lengths of the blow pipes all need to lie within strict boundaries. Otherwise they do not accurately fit between their pipe holders which may lead to leakages. Also expansions or shrinkages of the blow pipes which may well occur during temperature changes can lead to deformations 20 of the blow pipes themselves or of their pipe holders which in turn may lead to the seats no longer being able to properly close or open the flow paths towards the blow pipes. In order to prevent this, the blow pipes are mostly mounted with a certain axial play between the pipe holders at the blow pipe openings and the pipe holders at the main openings. This however may lead to oscillating movements of the blow pipes during use, which results in a lot of 25 noise being produced and which may lead to wear and damaging of seals placed between the pipe holders and the blow pipes.

The invention aims to overcome one or more of the abovementioned disadvantages at least partially or to provide a usable alternative. In particular the invention aims to provide a user-friendly and reliable multi-station pulse valve system which can be manufactured 30 environmentally friendly against low costs.

This aim is achieved by a pulse valve system according to claim 1. The system comprises a pressurized gas storage tank having an interior space. A main opening is provided in the tank wall. A blow pipe opening is provided in the tank wall at a position opposite of the main opening. Between the main and blow pipe opening a longitudinal blow 35 pipe is provided which extending through the interior space of the tank. A controllable pulse valve is mounted at the location of the main opening, and has a movable valve organ which is able to close or open a flow path for the gas between the interior space and an inlet end -3- of the blow pipe. According to the inventive thought one or more axially deformable spring organs are provided for exerting an axially directed flexible clamping force to the blow pipe.

If expansions or shrinkages of the blow pipe occur due to temperature changes, then this is no longer a problem since the spring organ(s) is well able to deform in the axial direction and 5 thus is able to compensate for the change in length of the blow pipe. Owing to this the blow pipe does not have to deal with large internal compressive stresses in the case of higher temperatures, nor can it start to oscillate between its supports in the case of lower temperatures. Another advantage is that the invention makes it possible to use blow pipes during manufacturing/assembly of which the precise length may be less accurate. The blow 10 pipes may well be a mm longer or shorter without this having to lead to rejections. Again the spring organs are well able to compensate for such deviant blow pipe lengths.

In a particular embodiment the pulse valve system further comprises a first pipe holder at the main opening for supporting the inlet end in the axial direction. This first pipe holder has a sleeve shaped part sealingly fitting around the inlet end of the blow pipe. The 15 sleeve shaped part comprises a seat for the valve organ to sealingly lie against in its closed position. In this closed position the sleeve shaped part may be crunched or otherwise clamped or mounted around the inlet end of the blow pipe. Support arms are provided which project radially outwardly form the sleeve shaped part. The support arms can then advantageously perform a double function. On the one hand they are able to properly 20 position the sleeve shaped part of the pipe holder and thus also the inlet end of the blow pipe at an aimed distance from the tank wall. The flow path for the gas to be able to flow from the interior space of the tank towards the inlet end of the blow pipe in the open position of the valve can then be left clear between the support arms. The support arms for this are divided around the circumference of the sleeve shaped part. On the other hand the support 25 arms may perform the function of the axially deformable spring organs. The support arms then in particular are formed as being at least partially axially flexible. The sleeve shaped part is then resiliently movable in said axial direction relative to the support arms in order to have the sleeve shaped part exert a force on the blow pipe in the axial direction towards the blow pipe opening.

30 It is noted that a construction with a semi-rigid pipe holder is already known from WO

2010/028813. In this publication the pipe holder however is merely provided with a number of snap arms which can spring in the radial direction. The purpose of this radial springing is to be able to insert the blow pipe into the tank via the main opening and to snap the blow pipe into position with its arms snapping behind an inwardly projecting edge of the tank as 35 soon as the outlet end of the blow pipe is properly placed into the blow pipe opening. The blow pipe opening for this comprises an inwardly projecting edge for forming an abutment for the blow pipe in the axial direction. The snap arms are made out of plastic such that they -4- are able to flex radially inwards. A flexing of the arms in the axial direction of the pipe is not possible since they project radially outwards at merely a small angle relative to the axial direction. Thus the length of the pipe with this semi-rigid pipe holder still needs to lie within strict boundaries and differences in length occurring during temperature changes can not be 5 compensated for. Also the snap connection makes it difficult to remove the blow pipe out of the tank again if desired for maintenance or other reason.

The support arms according to the invention may have all kinds of shapes and dimensions. Preferably they are made as flexible plate shaped wings. In particular the support arms then are given a thickness of less than 2 mm. For example the thickness may 10 be approximately 0,8 mm. The thin arms have the advantage that they do not block the flow path anymore than necessary. The thin arms make it possible for the gas to flow from the interior of the tank into the blow pipe while only having to make one bend. Fewer restrictions are to be overcome by the compressed gas when flowing into the blow pipe. This makes it able to maintain more energy inside the gas blows, owing to which the performance gets 15 slightly improved.

The first pipe holder can be made out of various materials like plastic. Preferably it is made out of metal, in particular stainless steel, since this material maintains its spring characteristics and does not have to deal with relaxation.

According to an environmentally friendly embodiment the first pipe holder has been 20 cold formed out of metal plate material. Polluting techniques like die casting or machining of a pipe holder with a lot of waist of material are then no longer needed. The sleeve shaped part can then for example easily be deep drawn out of the metal plate material.

In an embodiment the support arms have curved middle sections. Thus they are able to take up both axial play and length changes of the blow pipe, as well as expansion of the 25 blow pipe in the radial direction. The curved middle sections advantageously are concavely curved towards the valve such that they do not abut against parts of the valve or tank wall if they need to deform/flex in the axial direction.

Further embodiments are stated in the dependent subclaims.

The invention also relates to a use of a pulse valve system for blowing air into a dust 30 collector or filter installation in a direction opposite to a filtering direction so as to detach adhered dusts.

The invention shall be explained in more detail below with reference to the accompanying drawings, in which: 35 Fig. 1 shows a schematic cross sectional view of an embodiment of the pulse valve system according to the invention in an open position of the valve;

Fig. 2 shows an enlarged partial view of an upper part of fig. 1; -5-

Fig. 3 shows an enlarged partial view of a lower part of fig. 1;

Fig. 4 shows a perspective and cross sectional view of the first pipe holder of fig. 1;

Fig. 5 shows a perspective view of fig. 1 without the valve;

Fig. 6 shows a top view of fig. 1; 5 Fig. 7 shows a cross sectional view over the line B-B in fig. 6; and

Fig. 8 shows a view similar to the one of fig. 1 in which a plurality of adjacent pulse valves and blow pipes are to be seen.

In fig. 1 the valve system is referred to in its entirety with the reference numeral 1.

10 The system 1 comprises an extruded aluminium tank 2 having an interior space 3. The outer ends of the tank 2 are closed by end caps 4, inside one of which a gas inlet 5 is provided for feeding pressurized gas into the tank 2, for example via a compressor (not shown). At the upper side the tank 2 has a large number of circular so-called main openings 7 machined into the tank’s circumferential wall. A pulse valve 8 is bolted to the outside of the tank 2 at 15 the location of each main opening 7. The pilot operated valve 8 comprises a diaphragm 9 which can be positioned up and down between an open and a closed position against the action of a spring 10 (see fig. 2). The valve 8 can be of various types, like a solenoid operated valve or, as shown here, a remote operated valve. A control box (not shown) can be connected to the pulse valves 8 for periodically actuating them, that is to say to have 20 their diaphragm 9 move upwards against the action of the spring 10.

Directly underneath the main opening 7 a blow pipe 15 is provided which extends downwards through the interior space 3. At its upper end the blow pipe 15 comprises an inlet end 15a onto which a first pipe holder 16 is placed. The pipe holder 16 is cold-formed and punched out of stainless steel plate and has a deep-drawn central sleeve shaped part 25 16a (see fig. 4). The sleeve shaped part 16a at its upper side has an inwardly deflected curved edge which forms a seat 16a’ for the diaphragm 9 to lie sealingly against in the closed position. The seat 16a’ has been given a radius of a few millimetres, in particular approximately 2 mm. The inlet end 15a of the blow pipe 15 has been inserted into the sleeve shaped part 16a with its free end edge 15a’ abutting in the axial direction A against 30 the seat 16a’. Between the sleeve shaped part 16a and the inlet end 15a an O-ring 17 is placed. The sleeve shaped part 16a merges at four locations around its circumference into wings 16b. The wings 16b extend substantially in the radial outwards direction relative to the central sleeve shaped part 16a, and each start with a concavely curved part 16b’ which is substantially radially directed while being curved around a tangential direction, to end with a 35 straight part 16b” which is fully radially directed. The straight part 16b” lies abutting against axially inward edge parts 2’ of the tank wall circumventing the main opening 7.

-6-

Between the curved part 16b’ and the straight part 16b” a centring projection 16b’” is provided (only shown in fig. 2) which lies against radial inward edge parts 2” of the tank wall circumventing the main opening 7. The centring projections 16b’” of al the wings 16b together centre the seat 16a’ and inlet end 15a of the blow pipe neatly in front of the 5 diaphragm 9.

The blow pipe has an outlet end 15b which is sealingly held inside a second pipe holder 20. This pipe holder 20 comprises a sleeve shaped part 20a into which the outlet end 15b has been inserted with its free end edge 15b’ abutting in the axial direction A against an inwardly projecting flange 20a’. The pipe holder 20 further comprises a mounting flange 20b 10 with which it is bolted against the tank wall 2, while its sleeve shaped part 20a extends through a circular so-called blow pipe opening 22. The blow pipe openings 22 are machined into the tank’s circumferential wall at diametrically opposite positions of the main openings 7. At their lower ends the pipe holder 20 comprises a connection 20c for connecting the blow pipe 15 via an additional blow pipe to a filtering cloth of a filter installation (not shown).

15 During use the tank 2 is filled with a pressurized gas, in particular at pressures between 0-10 bar. The gas most of the time can be environmental air. Each time that it is desired to have an amount of the gas blow out of the blow pipe 15 into the filtering cloth of the filter installation in order to blow any particles like dust free form the filtering cloth’s surface, the pilot operated pulse valve 8 is operated by means of the control means in such 20 a way that the diaphragm 9 moves upwards from the closed position in which it lied sealingly against the seat 16a’ towards the open position as shown in fig. 1 and 2. In this open position a play is obtained between the diaphragm 9 and the seat 16a’. Thus a flow path arises which starts in the interior space 3 of the tank 2, and from there runs in between the wings 16b, over the seat 16a’ into the inlet end 15a of the blow pipe 15. This flow path is 25 shown with the arrows FP in fig. 1.

Advantageously the first pipe holder 16 out of thin metal plate material does not block the flow path anymore than needed with only a few energy taking restrictions like corners, in- and outlets, etc. This helps to prevent loss of pressure of the gas flow to occur and/or prevents turbulences to be introduced into the gas flow. Thus the flow path FP is hardly 30 restricting the pulse performance. This is even further improved by the downwardly concavely curved parts 16b’ of the wings 16b which make it possible for the gas to flow quicker with larger amounts and at less steep angles into the blow pipe 15. Not only is the first pipe holder 16 able to clamp and hold the blow pipe 15 into position horizontally, it is also able to position the seat 16a’ in the axial direction and to take up any tolerance stack of 35 the assembly of blow pipe 15, pipe holder 20 and valve 8 in the axial direction.

In the case of temperature changes the flexible wings 16b offer freedom for the blow pipe 15 to expand or shrink in the axial direction by flexing somewhat upwardly or -7- downwardly. Furthermore the flexible wings 16b are able to take up deformation caused by blowing up of one or more parts of the system because of the high pressures occurring during use. Owing to the curved parts 16b’ the blow pipes also have the freedom to expand or shrink somewhat in the radial direction by curving somewhat more or less. The centring 5 projections 16b’” then still keep the assembly perfectly centred and prevent the straight wing parts 16b” to start sliding along the tank wall during this deformation.

Besides the embodiment shown numerous variants are possible. For example the various parts may have other shapes and dimensions and be made out of different materials. The system can be used in combination with partly or fully cylindrical tanks but 10 also with other geometries like square ones. In case of an overhaul the various parts of the system, including the first pipe holder, can easily be replaced and repaired. Instead of four wings other numbers are also possible. Instead of using the valve system for blowing through filter installations and the like it can also be used for other purposes like blowing confetti into a room or other situations where a quick exhaust of an amount of gas is 15 required. Instead of using a pipe holder with axially flexible wings, it is also possible to use other forms shapes and types of support arms, as long as they are able to exert the required axially directed flexible clamping force to the blow pipe. In the alternative or in addition it is also possible to add an axially deformable spring organ between the blow pipe and one of its axial supports. For example an axially compressible spring organ may be placed between 20 the second pipe holder and the outlet end of the blow pipe and/or between the first pipe holder and the inlet end of the blow pipe.

Thus according to the invention a low cost and environmentally friendly valve system is obtained having improved pulse flow characteristics.

25

Claims

A pulse valve system for controllable blowing out of pressurized gas through a blow pipe, comprising: - a storage tank for pressurized gas with an inner space; - a main opening provided in the tank wall; 5. a blow pipe opening provided in the tank wall at a position opposite the main opening; - a blow pipe with an axial direction, which extends through the inner space from the main opening to the blow pipe opening; - a controllable pressure valve mounted at the position of the main opening, and with a valve member movable in the axial direction for closing / opening a flow path for the gas to flow out of the inner space into an inlet end of the blowpipe in an open position of the valve, characterized in that one or more spring members are provided for exerting an axially directed flexible clamping force on the blow pipe. 15

A pulse valve system according to claim 1, further comprising: - a first pipe holder at the main opening for supporting the inlet end in the axial direction, the first pipe holder having a sleeve-like part that fits sealingly around the inlet end 20 and radially outwardly directed support arms has said supports against the tank wall, wherein the sleeve-shaped part comprises a seat for the valve member to abut sealingly in a closed position of the valve, and wherein the radially outwardly directed support arms position the sleeve-shaped part and inlet end at a distance from the tank wall in order to limit the flow path, wherein the support arms form the spring members.

A pulse valve system according to claim 2, wherein the support arms are made as flexible plate-shaped wings.

A pulse valve system according to claim 3, wherein the support arms have a thickness of less than 2 mm.

A pulse valve system according to claim 3 or 4, wherein the first pipe holder is cold formed from metal sheet material. 35

A pulse valve system according to claim 5, wherein the sleeve-shaped part is deep-drawn from the metal plate material.

7. A pulse valve system according to any of claims 2-6, wherein the support arms are shaped such that the sleeve-shaped member is resiliently movable in the axial direction relative to the support arms to allow the sleeve-shaped member to exert a force on the blowpipe in the axial direction to the blow pipe opening.

A pulse valve system according to any of claims 2-7, wherein the support arms have curved center sections. 10

A pulse valve system according to claim 8, wherein the curved center sections are concave curved toward the valve.

A pulse valve system according to any of claims 2-9, wherein each support arm 15 has a centering protrusion that rests against a radial wall portion of the tank.

A pulse valve system according to any of claims 2-10, wherein a total number of four support arms are provided.

A pulse valve system according to any of the preceding claims 2-11, wherein the first pipe holder is made of stainless steel and / or spring steel.

A pulse valve system according to any of the preceding claims, further comprising: 25. a second pipe holder at the blow pipe opening for supporting the outlet end in the axial direction, the second pipe holder having a sleeve-shaped part that fits sealingly around an outlet end of the blow pipe and wherein the second pipe holder is mounted on the tank wall. 30

Use of a pulse valve system according to any one of the preceding claims, for blowing air into a dust collector or filter installation in a direction opposite to a filter direction to release dust particles so attached.