GB2430019A

GB2430019A - Pipeline pig launching trap

Info

Publication number: GB2430019A
Application number: GB0617419A
Authority: GB
Inventors: Walter Robert Suttie
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-09-10
Filing date: 2006-09-05
Publication date: 2007-03-14
Anticipated expiration: 2026-09-05
Also published as: GB0518526D0; GB0617419D0; GB2430019B

Abstract

A pipeline pig launching trap includes a casing 102 having a launching chamber 105 and a port 112 leading to a pipeline entry section 12, and also including a device 106, 110 for displacing a pig 116 positioned in the launching chamber 105 into the pipeline entry section 12. The casing 102 also includes a stand-by chamber 107, means 106, 110 for closing the port 112 leading to the pipeline entry section 12, and a moveable support 114 for the pig 116. The moveable support 114 is moved so that the pig 116 enters the launching chamber 105 for deployment into the pipeline via the pipeline entry section 12. The pig 116 is deployed by pushing it using the displacement device 106, 110, which preferably doubles up as the means 110 for closing the port 112. This trap allows the pig 116 to be cleaned by CIP (cleaned in place) fluid during normal operation of a system in which the trap is fitted.

Description

- 2430019 Pipeline pigging apparatus The invention relates to pipeline

pigging apparattis, that is to say to apparatus whereby so-called pipeline pigs, which are plugs of an interference fit in the pipelines concerned, can be used to clean the interior surfaces of the pipelines and can also be used to reclaim substances which would otherwise be wasted.

In a wide range of manufacturing industries where batch production of products is carried out, pipework which is used for the transfer of various ingredients, or indeed for the delivery of finished fluid product, will frequently need to be purged from time to time before being employed for the transfer of other ingredients or other finished products, and this will increasingly involve the use of pipeline pigs.

Since pipeline pigs are, in effect, moving barriers separating the product from the propelling medium they are usually made at least in part of a resilient material, being of spherical or generally cylindrical form. When a cleaning operation is to be carried out, the pigs are usually propelled through the pipelines concerned under gas or liquid pressure and, being slightly oversize, that is to say each being made of a diameter slightly greater than the bore diameter of the pipeline concerned, they clean the pipelines to a standard largely dependent upon the condition of their resilient sealing surfaces.

Pipeline pigging apparatus for reclaiming product which would otherwise be degraded or wasted by being drained or flushed from the pipelines concerned is increasingly being employed in process industries, for example in the foodstuffs and beverage manufacturing and dairy industries. The reasons for this include recent legislation limiting the production of waste together with other environmental considerations, cost of disposal of waste (including increased water charges) and also operational considerations, for example to reduce to a minimum the downtime resulting from removal of waste product from pipes which are to be used for conveying a different product. Also a factor is the aim of manufacturers themselves to introduce more stringent quality control measures; if a pipeline is effectively emptied of one product before the next product is pumped through it, this greatly contributes to improved quality control. The more old established methods of expelling the remains of a first product which includes draining, blowing with air, pumping and degrading a mixture of a first arid second product are notoriously wasteflul and ineffective.

However, it has been found that the existing technology for pipeline pigging cannot easily be transferred where, for example, foodstuffs and pharmaceutical products are concerned; in particular, higher standards of hygiene and lower propulsion pressures are required.

In pipework installations where there is a substantial length of pipeline between a product store and a production machine using the product, a considerable cost saving can be made if the product in the length of pipeline can be reclaimed on completion of a production run; this can be a particularly important consideration in those installations where frequent changes of product are made and/or where the substance concerned is a relatively high value material, In addition, savings in capital costs of plant can be made if one pipeline can be used, selectively, for many different products rather than dedicated pipelines having to be provided for each product; it is vital in these circumstances that the product reclaiming and pipeline cleaning systems are both effective and reliable.

If used in the foodstuffs manufacturing or pharmaceutical industries in particular, a vitally important requirement is that pigging apparatus should be able to be cleansed, by routine cleaning, to a very high standard in a short space of time and should remain free from contamination throughout its use, that is to say between those times when routine cleaning is carried out. However, again in the foodstuffs and pharmaceuticals industries in particular, it is in fact thought, by many people in authority, that whenever a pig is extracted from a pipeline system there is a risk that the hygienic integrity of the system may be affected. Consequently, in these industries there is, to a very great extent, a desire to rely on CIP (clean in place) fluid to clean the pigs in situ rather than to remove them for cleaning, but the cleaning of certain types of pig in situ can be a problem. This problem has been found to be particularly acute where the pigs concerned have been of generally cylindrical form and provided with groups of closely spaced resilient discs. Such pigs have been found to have distinct advantages over other types of pig, particularly in the fact that the pressure of fluid propelling the pig augments the initial sealing pressure produced by the resilience of the material of which the resilient discs are made, and also in the fact that the resilient discs of each group of discs can be arranged to abut together in use for mutual support, thus allowing the use of individual discs which are relatively soft and floppy and resulting in a construction of pig which can be propelled along a pipeline by a relatively low propulsion pressure so that the system is inherently safe; in addition it has been found that such pigs can travel around bends of relatively small radius and can pass freely along pipelines which have suffered local deformations to an extent which would be likely to cause jamming of previous forms of pig or require excessive propulsion pressures to be used to avoid such jamming taking place, this being a procedure which should never be used because of the very real safety hazard which it involves. However, it will be readily understood that the close spacing of the resilient discs of this form of pig makes it particularly difficult to clean the pig adequately by the use of CIP (clean in place) fluid. It is this fact in particular which has caused the adoption of this advantageous form of pig to take place only very slowly in the foodstuffs and pharmaceutical industries, and it is this problem which the present invention seeks to address.

According to one aspect of the invention, there is provided a pipeline pig launching trap including a casing having a launching chamber, a stand- by chamber and a port leading from said launching chamber to a pipeline entry section; means for closing said port; laterally moveable means for displacing a pig positioned in said launching chamber into said pipeline entry section when said port has been opened; and moveable means whereby the pig can be moved from a position within the stand-by chamber to a launch position within said launching chamber when said laterally moveable means have been retracted, and can subsequently be returned to said stand-by chamber from said launching chamber, the arrangement being such that, when a pipeline pig is to be launched from the trap, firstly, the means for closing the port leading to the ppeRne entry section can be opened, secondly, the moveable means can be actuated to bring the pig supported thereby into its launch position between the laterally moveable means and the pipeline entry section and, thirdly, said laterally moveable means can be actuated to push the pig into the pipeline entry section, the port leading to said entry section then being closed. The means for closing the port leading to the pipeline entry section and the laterally moveable means for displacing a pig positioned in the launching chamber may be constituted by a plunger carrying a sealing member and forming part of a first actuator, The moveable support means may be constituted by a support plate carried by the push rod of a second actuator.

The stand-by chamber may be located beneath the launching chamber, in which case the second actuator will be located on the underside of the launching trap.

Alternatively, the stand-by chamber may be located above the launching chamber in which case a third actuator may be provided for retaining the pig in said stand-by chamber when the second actuator has been retracted.

The launching chamber and the stand-by chamber may be located side by side in a horizontal plane and in this case the means for moving a pig from one chamber to the other may be constituted by the second actuator and a fourth actuator arranged in horizontally opposed relation to said second actuator, said actuators being caused to function selectively.

There may be provided a pipe connection into the pipeline entry section, the arrangement being such that, when a pig has been pushed into said entry section and the port leading to it then closed, air under pressure can be admitted to the pipeline entry section by way of said pipe connection to act upon the pig and cause it to be projected along the pipeline.

There may also be a pipe connection for a supply of CIP(clean in place) fluid into an upper region of the trap casing and, in addition, a drain pipe opening from a lower region of said casing, said drain pipe being provided with an isolation valve, the arrangement being such that, throughout normal "production of product" mode of operation of a pipeline system of which the launching trap forms a part, when the port leading to the pipeline entry section is closed, a pig or pigs located within the launching trap can be cleaned by CIIP(clean in place) fluid entered into it through said pipe connection and exiting the trap through said drain pipe.

According to another aspect of the invention, there is provided a pipeline system including at least one pipeline pig launching trap as described above.

In the accompanying drawings, which illustrate, by way of example only, particular embodiments of the invention:- Figure 1 is a schematic view of a pipeline system embodying the invention, Figure 2 is a semi-diagrammatic part-sectional side view of a pipeline pig launching trap forming part of the system illustrated in Figure 1, this being drawn to a larger scale than Figure 1, Figure 3 is an end view of the trap in the direction of arrow 3 in Figure 2, Figures 4 to 8 are views similar to Figure 2 which will be referred to when describing the operation of the system, Figures 9 and 10 are views similar to Figures 2 and 3 which will be referred to when describing a first possible modification of the launching trap, Figures 11 and 12 are views similar to Figures 2 and 3 which will be referred to when describing a second possible modification of the launching trap, and Figures 13 and 14 are views similar to Figures 2 and 3 (except that Figure 13 is in this case a part-sectional plan view of the launching trap and Figure 14 is a side view looking in the direction of the arrow 14 in Figure 13) which will be referred to when describing a third possible modification of the launching trap.

Referring now to Figure 1 of the drawings, the pipeline system there illustrated includes a pipeline pig launching trap, generally indicated 10, which will be described in detail presently, this being connected, by way of a pipeline entry section 12, to a pipeline 16. The pipeline 16 leads, by way of a valve 18, to an inlet pipe 20 for a filling machine (not shown) - or the inlet pipe 20 could feed a manifold connected to a plurality of filling machines all drawing the same liquid or substance from that common source - and it will be understood that the filling machine or filling machines can be of any type depending on the liquids or substances being packaged. (It Will be understood that the system may equally well be used for other purposes, for example for feeding a fluid ingredient to a mixing machine in a process industry, but for the sake of simple illustration the system will hereinafter be described as being for the feeding of a finished fluid product to a filling machine or filling machines). A stop member, in the form of a metal pin 22 extending across the diameter of the pipeline, is closely spaced from the valve 18 for a purpose which will presently be described. A valve 24, for admitting air under pressure to the pipeline from an air line 26, via a one way valve 28, is located between the stop member 22 and the valve 18.

At an upstream end of the pipeline 16, and immediately alongside the pipeline entry section 12, there is a lateral pipe connection 30, this communicating, by way of a butterfly valve 32, with a product store (not shown) from which, throughout the normal operation of the system, a required product is pumped to said pipeline. However, at other times, that is to say between times of normal operation of the system, when the system is being prepared for the transfer of a different product, CIP (clean in place) fluid will be pumped into the pipeline system, from a source not shown, through this same lateral pipe connection 30; it may be routed into the system via the pump (not shown) by means of which the product is pumped into the system.

A pipe connection 34 (see Figure 2) into the pipeline entry section 12 is shown to be connected to a valve 36 leading to a supply pipe 38 for air under pressure. The valve 36 remains closed throughout the normal operation of the system, that is to say whenever product is being pumped through the pipeline to the filling machine or filling machines. A number of detector devices 40 are located alongside the pipeline to detect the presence of a pipeline pig in their regions during a pigging operation.

Referring now in particular to Figures 2 and 3, the pipeline pig launching trap, generally indicated 10, includes a casing 102 with a removeable top cover 104.

Within the casing an uppermost space constitutes a launching chamber 105 and a space beneath said launching chamber constitutes a stand by chamber 107.

Immediately beneath the top cover of the casing there is located mechanism which can be referred to broadly as laterally moveable means, that is to say a plunger 106 forming part of a first pneumatic actuator, generally indicated 108 The plunger 106 carries a sealing member 110 which, when the actuator has been operated to extend the plunger, closes a port 112 leading to the pipeline entry section 12. In this particular arrangement therefore the plunger performs a dual function, being the means for closing the port 112 and also being the means for displacing a pig positioned in the launching chamber into the pipeline entry section, as will presently be described.

In a lower portion of the casing there is located mechanism which can be referred to broadly as vertically moveable support means, that is to say a support plate 114 for a pipeline pig 116 (shown here in chain dotted lines as being, in this instance, of the kind having a generally cylindrical body with resilient discs, or groups of such discs, at its opposite ends), the support plate being mounted at the upper end of the push rod 118 of a second pneumatic actuator 120 located on the underside of the launching trap. At one side of said lower portion of the casing there is an opening 122, shown to be sealed by a cover plate 124, and at the opposite side of said casing there is an opening to a drain pipe 126, this being provided with an isolation valve 128. Into the upper portion of the casing there is connected a CIP (clean in place) supply pipe 130, this being provided with a valve 132 which will be closed throughout normal "production of product" mode of the pipeline system. The supply pipe 130 is connected to the supply of CIP (clean in place) fluid independently of that previously referred to as flowing through the pipe connection 30 when the pipeline 16 is to be cleaned.

Referring now to Figures 4 to 8, these illustrate the functions of the launching trap throughout the operation of the pipeline system, as follows:- In Figure 4 the launching trap is shown in the condition it has throughout normal "production of product" mode of the pipeline system, that is to say -10-P whenever a fluid product is flowing through the pipeline as indicated by the arrows, the sealing member 110 being shown to have closed the port 112. A pipeline pig is shown to be located on the support plate 114 in the stand-by chamber. During this period it would, of course, be possible to remove the cover plate 124, as indicated in chain-dotted lines, in order to remove the pig for inspection, repair or replacement.

In Figure 5 the valve 32 has been closed so that flow of product has ceased and the first pneumatic actuator 108 has retracted the sealing member 110 to open the port 112. Following that initial retraction of the sealing member 110, the support plate 114 has been raised by the operation of the second actuator to bring the pig located on said support plate into co-axial alignment with the pipeline entry section 12 and with the first pneumatic actuator.

In. Figure 6 the first pneumatic actuator 108 has been again extended to push the pipeline pig through the pipeline entry section and to once again cause the sealing member 110 to close the port 112. In the position in which it is shown in Figure 6, the pig can be acted upon by air under pressure admitted to the pipeline entry section through the pipe connection 34, the pig being thus projected down the pipeline to reclaim product in the pipeline and to ensure that the pipeline is virtually free of all traces of that product before it is used for the transfer of some other material or substance. When the pig has been brought to a halt by the metal pin 22 at the far end of the pipeline, it will, during its travel, have returned to a recovered product store (not shown) - or in fact to any convenient vessel for future use - a volume of product equal to the volume which it has displaced in its movement along the pipeline. The relatively

-U-

small volume of product remaining in the filling machine inlet pipe 20 can be subsequently flushed out by CIP (clean iii place) fluid.

In Figure 7 the pipeline pig is shown to have been returned to the launching trap (by the admission of air under pressure from the air line 26 on the opening of valve 24) and, mounted on the support plate 114, to have been returned to its former position in the stand by chamber of said trap. In this position, with the valve 18 closed and the isolation valve 128 open, CIP (clean in place) fluid can be injected under pressure into the launching trap from the supply pipe 30.

With the CII' (clean in place) fluid flowing laterally across the resilient sealing discs of the pig, as indicated by the arrows in Figure 7, it is thought that the pig is likely to be cleaned to a high standard in this way. During the cleaning operation it may be found advantageous to operate the second pneumatic actuator 120 a number of times, thus adjusting the vertical location of the support plate in order to vary the fluid flow over the pig, but the fluid will still flow substantially laterally across the sealing discs throughout the operation to be as effective as possible. Also, during at least some part of the cleaning operation, air under pressure may be introduced through the pipe connection 34 to increase the volume of foam produced by the CIP (clean in place) fluid and to maximise turbulence within the trap casing.

In Figure 8 the first pneumatic actuator 108 has again been operated to cause the sealing member 110 to close the port 112, and the valve 132 has been opened to allow the flow of CII' (clean in place) fluid directly into the casing of the launching trap through the CIP (clean in place) supply pipe 130, the isolation valve 128 still being open to allow the fluid to drain away (or to be recirculated as the case may be) it will be understood that to clean the pig to an even higher standard of cleanliness in this way it will be possible to circulate the CIP (clean in place) fluid through the launching trap for an extended period of time, that is to say whilst the pipeline system is in normal operation, without the cleaning operation causing extended down time. In other words, normal delivery of product can proceed whilst cleaning of the pig is carried out.

Thus there is provided a form of pipeline pig launching trap which has a number of advantages. For example, in addition to the advantages pointed out above, a launching trap embodying the invention avoids the need for a fill bore (hygienically cleanable in service) ball valve which has previously been required to admit a pig into a pipeline, such fill bore, hygienically cleanable, ball valves being very expensive. In addition to this, the standard of cleanliness of such ball valves is difficult to veriiy and there are people in authority who prefer not to use such valves fo this reason. It will also be understood that, since a pipeline pig can only be extracted from a launching trap embodying the invention through the opening 122, a pipeline system including the trap will be inherently safe; an excess of pressure projecting a pig along the pipeline could not possibly project it at lethal velocity through the opening 122.

In Figures 9 and 10 there is illustrated a first possible modification of the launching trap described above. As shown, this modification is basically the same as that described earlier except that the depth of the casing 102 has been increased so that a pair of pipeline pigs 116,116 can be accommodated within the stand-by chamber, as shown. The second pneumatic actuator 120 will have been given a greater working stroke and will be able to operate in two stages, a first stage of its movement bringing a first one of the pigs into its launch position and a further stage of its movement bringing a second one of the pigs into its launch position some time later according to the working requirements of the particular pipeline system.

Referring now to Figures 11 and 12, these illustrate a second possible modification of the launching trap originally described. As shown, this modified form of trap is again basically the same as that first described, except that in this case a space above the launching chamber 105 constitutes the stand-by chamber 107 and a third pneumatic actuator 134, including an extendable detent rod 136, is located in a side wall of the casing 102 As before, a pipeline pig located in the stand-by chamber is shown in chain-dotted lines; it is shown to have been raised to that position by the support plate 114 (which has then been returned to its lowered position) the pig being retained within the stand-by chamber by the detent rod 136 having been extended to its operative position.

It will be understood that, as drawn, this second possible modification of the launching trap is shown with the sealing member 110 in its retracted position.

In this condition, during or immediately following the pipeline being purged, CIP(clean in place) fluid may be admitted through the supply pipe 130 to clean the pig and to exit the casing through the drain pipe 126 Although not shown in the drawing, the casing 102 could be provided with a removeable cover plate 124 for an aperture in the casing through which a pipeline pig in the stand-by chamber could be inspected or removed for replacement by a new pig. It will also be understood that this second possib(e modification of the launching trap could be further modified in order to accommodate a pair of pipeline pigs, one vertically above the other, within the stand-by chamber, in a manner similar to that illustrated in Figures 9 and 10.

Referring now to Figures 13 and 14, these illustrate a third possible modification of the launching trap originally described. As shown, this modified form of trap is again basically the same as that previously described except that in this case the launching chamber 105 and the stand-by chamber 107 are arranged side by side in a horizontal plane and the second pneumatic actuator extends through a side wall of the casing 102. The push rod 118 (in this case devoid of support plate 114) is shown in Figure 13 to be capable of moving a pig laterally from a position in the launching chamber to the position in which it is shown in the standby chamber. A fourth pneumatic actuator 138 is provided to extend through the side wall of the casing opposite the actuator 120, the push rod 140 of the actuator 138 being capable, when extended, of returning the pig from its position in the stand-by chamber to its launch position in the launching chamber. For the sake of simple illustration the flow of CIP(clean in place) fluid to and from the casing is not shown iii these views but it will be understood that, having been illustrated previously in connection with previously described embodiments of this invention, this will not be difficult to arrange.

Various other modifications may be made. For example, it will be understood that the laterally moveable means forming part of a launching trap embodying the invention need not necessarily be constituted by pneumatic actuators. In the case of the launching trap illustrated in Figures 2 and 3, the two fi.inctions of the first pneumatic actuator 108, that is to say of closing the port 112 and of acting on a pig to push it into the pipeline entry section, could be performed by two separate mechanisms. Similarly, the vertically moveable support means need not necessarily be as described and illustrated by way of example.

Furthermore, either one or both of the laterally moveable means and the vertically moveable support means could be hydraulically operable instead of pneumatically actuated, or could be electrically operable from a remote source.

Either one or both could even be manually operable. A further possible modification would be to inject the CJP (clean in place) fluid into the trap so that it impinges on the or each pig tangentially, causing a swirling action of fluid within the casing and a spinning of the or each pig, substantially as described in my Patent No. GB2348939. Although the pigs illustrated in the drawings are of cylindrical form it will be understood that they could equally well be spherical; also that cradle means may be provided within the trap casing to locate the pig or pigs during cleaning, such cradle means for example being provided by a number of curved rods acting to loosely locate the pig or pigs when not being acted upon by the laterally moveable means or the vertically moveable support means. The side walls of the trap casing may be formed with guides along which the movements of the or each pig can take place smoothly without risk of its orientation being upset.

Claims

Claims 1. A pipeline pig launching trap including a casing having a

launching chamber, a stand-by chamber and a port leading from said launching chamber to a pipeline entry section; means for closing said port; laterally moveable means for displacing a pig positioned in said launching chamber into said pipeline entry section when said port has been opened, and moveable means whereby the pig can be moved from a position within the stand-by chamber to a launch position within said launching chamber when said laterally moveable means have been retracted, and can subsequently be returned to said stand-by chamber from said launching chamber, the arrangement being such that, when a pipeline pig is to be launched from the trap, firstly, the means for closing the port leading to the pipeline entry section can be opened, secondly, the moveable means can be actuated to bring the pig supported thereby into its launch position between the laterally moveable means and the pipeline entry section and, thirdly, said laterally moveable means can be actuated to push the pig into the pipeline entry section, the port leading to said entry section then being closed.
2. A pipeline pig launching trap according to claim 1, in which the means for closing the port leading to the pipeline entry section and the laterally moveable means for displacing a pig positioned in the launching chamber are constituted by a plunger carrying a sealing member and forming part of a first actuator.
3. A pipeline pig launching trap according to either one of the preceeding claims, in which the moveable support means are constituted by a support plate carried by the push rod of a second actuator.
4 A pipeline pig launching trap according to claim 3, in which the standby chamber is located beneath the launching chamber and the second actuator is located on the underside of the launching trap.
5. A pipeline pig launching trap according to claim 3, in which the standby chamber is located above the launching chamber and a third actuator is provided for retaining a pig in said stand-by chamber when the second actuator has been retracted
6. A pipeline pig launching trap according to claim 3, in which the launching chamber and the stand-by chamber are located side by side in a horizontal plane, the means for moving a pig from one chamber to the other being constituted by the second actuator and a fourth actuator arranged in horizontally opposed relation to said second actuator, said actuators being caused to function selectively.
7. A pipeline pig launching trap according to any one of the preceding claims, in which there is provided a pipe connection into the pipeline entry section, the arrangement being such that, when a pig has been pushed into said entry section and the port leading to it then closed, air under pressure can be admitted to the pipeline entiy section by way of said pipe connection to act upon the pig and cause it to be projected along the pipeline.
8. A pipeline pig launching trap according to any one of the preceding claims, in which there is a pipe connection for a supply of CIP(clean in place) fluid into an upper region of the trap casing and, in addition, a drain pipe opening from a lower region of the trap casing, said drain pipe being provided with an isolation valve, the arrangement being such that, throughout normal "production of product" mode of operation of a pipeline system of which the launching trap forms a part, when the port leading to the pipeline entry section is closed, a pig or pigs located within the launching trap can be cleaned by CJP(clean in place) fluid entered into it through said pipe connection and exiting the trap through said drain pipe.
9. A pipeline pig launching trap according to any one of the preceding claims, in which the stand-by chamber is located beneath the launching chamber and the second pneumatic actuator is located on the underside of the launching trap.
10. A pipeline pig launching trap constructed, arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by Figures2to8,orFigures9and 1O,orFigures 11 and 12,orFigures 13 and 14 U1 accompanying drawings.
11. A pipeline system including at least one pipeline pig launching trap constructed arranged and adapted to be used substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.