Description

This invention relates to a liquid injector and particularly to an injector for impregnating timber with a liquid wood preservative and also to a preservative jacket for timber poles, eg telegraph poles.

A liquid injector is disclosed in W090/11172, the injector being gas-loadable and cc«mprising an accumulator for containing a liquid and a propellant gas, a liquid delivery- tube for insertion into a timber to be treated by the liquid and intermediate means between the liquid delivery tube and the accumulator designed to establish a flow path for the liquid from the accumulator to the liquid delivery tube, on final installation of the injector.

The prior device is designed to be stored ready for installation, with the liquid under pressure from the propellant gas.

The disadvantage of the prior device is that if it is left in store for an extended period in its charged condition it is liable to lose its propellant gas pressure before it is installed.

Furthermore, it has been found that in telegraph poles not only does rotting occur within the core of the pole but also in the surface of the pole and that such surface rotting is of a different nature to the core rotting, thus requiring specific targetted liquid preservations appropriate to each pole than for core rotting. In my International Patent Application published under No WO90/11172, I have disclosed embodiments of a liquid injector which are designed to be screwed or hammered into a bore extending from the surface of a telegraph pole to its core so that liquid preservative can be injected, under controlled conditions, to treat the core rotting.

A further object of this invention is to extend the use of such injectors to the treatment of surface rotting.

It is to be recognised however, that the invention can also be used with other forms of liquid preservative jackets.

A preservative jacket for timber poles has been disclosed in US Patent Specification No 4,731,267. This jacket however is applied as a wet dressing and requires the operative to be exposed to the treatment liquid, which in some cases are, to say the least, unpleasant. Furthermore, such a jacket requires to be replaced when the liquid preservative has been exhausted.

The present invention aims to overcome or at least mitigate the disadvantages associated with the above prior devices.

According to one aspect of the present invention there is provided a li-quid injector comprising an accumulator having a liquid compartment and a second compartment separated from the liquid compartment by a wall having therein gas-diffusable filter means, the second compartment being intended for loading with two or more gas-generating agents, one of which agents is a liquid contained in a sachet, and the second compartment having a flexible closure which is so designed that, on depression thereof onto the sachet, the sachet is ruptured so that the agents can react together to produce a supply of pressurised propellant gas.

According to a further aspect of the present invention there is provided a liquid injector comprising an accumulator having a liquid compartment and a second compartment separated from the liquid compartment by a wall having therein ^" means for opening communication from the second compartment to the liquid compartment upon creation within the second compartment of an overpressure, the second compartment being intended for loading with two or more gas-generating agents, one of which agents is a liquid contained in a sachet, the injector being so designed that on deliberate displacement of the liquid and second compartments relative to the tube, the liquid compartment is put into flow communication with the tube and the sachet is ruptured so that the agents can react together to produce a supply of pressurised propellant gas.

According to a still further aspect of the present invention there is provided a liquid injector comprising an accumulator having a liquid compartment and a second compartment separated from the liquid compartment by a wall having therein means for opening communication from the second compartment to the liquid compartment upon creation within the second compartment of an overpressure, the second compartment being intended for loading with two or more gas-generating agents, one of which agents is a liquid contained in a container having a rupturable closure membrane, the injector being so designed that on deliberate displacement of the liquid and second compartments relative to the tube, the liquid compartment is put into flow communication with the tube and the closure membrane is ruptured so that the agents can react together to produce a supply of pressurised propellant gas.

Thus, provided that no such deliberate displacement takes place, the injector can be stored for an indefinite period and be ready for use when required.

According to a still further aspect of the present invention there is provided a preservative jacket for timber poles, comprising an outer or backing layer of impervious flexible material, an inner layer for contact with the surface of the pole, the inner layer being of pervious material, and absorbent material held between the said layers, and wherein a liquid distribution collar is set into the layers to permit liquid to be injected into the absorbent material from a liquid injector applied to the collar.

With the jacket of the present invention, the operative is not exposed to the liquid preservative. Furthermore, the preservative can be replenished without replacing the jacket.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is an exploded axial section of an injector according to one aspect of the present invention;

Fig la is a cross-sectional view on the line A-A of Fig 1;

Fig lb is a cross-sectional view of the tube of Fig la in use;

Fig. 2 is an exploded axial section of an injector according to a further aspect of the present invention;

Fig. 3 is an axial section of the injector of Fig 2 in an assembled and active condition, the preservative liquid and pressurising agents contents having been omitted.

Fig. 4 is an exploded axial section of an injector according to a still further aspect of the present invention;

Fig. 5 is an axial section of the injector of Fig 4 in an assembled and active condition, the preservative liquid and pressurising agents contents having been omitted;

Fig 6 is a pictorial view of a jacket according to a further aspect of the invention, from the inner side;

Fig 7 is a pictorial view of the jacket of Fig 6 from the outer side;

Fig 8 is an enlarged view of the jacket of Fig 6 showing a liquid distribution collar in greater detail;

Fig 9 is a sectional view of a portion of a timber pole showing the jacket of Fig 6 installed with two injectors, the right-hand one serving to treat the core as disclosed in WO90/11172 and the left-hand one cop-operating with the jacket to treat the surface of the pole; and

Fig 10 is a pictorial view corresponding to Fig 9 but showing the jacket partially buried and the injectors completely buried.

In Figs 1 and 2, an ^' injector comprises an accumulator formed of a first plastics shell 1 and a second plastics shell 2 fused together at their rims 3, eg. by ultrasonic welding. The shell 1 has a re-entrant wall 4 having therein four gas- diffusable filters 5, one disposed centrally and the three others equally spaced apart about the central one. Similarly the shell 2 has a re-entrant wall 6 which defines an annular socket 7 with an integral inner wall 8. The wall 8 itself defines a central socket 9. The space within the shells 1 and 2 and between the walls 4 and 6 define a compartment 10 for liquid wood preservative.

Between the wall 4 and a closure 11 therefore is a second compartment 12 intended for loading with two or more gas- generating agents. One of these agents is a liquid contained in a sachet 13. The closure 12 has a flexible portion 14 with a sprue or point which can rupture the sachet 13. A plunger 15 is slidably received in a cylindrical socket 16 of the closure 11.

A flexible tube 17 has at one end an insert 18 also inserted into an opening in the floor of the socket 9. The insert 18 is covered by a rupturable membrane 19. The tube 17 is formed of thin walled tubing which has a plurality of thickened wall portions 17a as shown in Fig la. A weighted insert 20 is provided at the free end of the tube 17. The insert 20 causes the tube 17 to bend about 90° in the compartment 10 and the thickened wall portions ensure that a passage is maintained through the tube for liquid flow. As shown in Fig lb, one of the thickened wall portions is always located at the side of the tube which tends to open the flow passage

A liquid delivery tube 21 has a flange 22 on one face of which there is a gasket 28 surrounding a tube 21 A skirt 23 extends from the other face of the flange 22 and forms a snug sleeve for the wall 8. The skirt 23 is retainable in the socket 7 by means of a spragging washer 24. Also extending from the flange 22 is a central socket 25 in which there is an insert 26 from which extends a narrow tube 27 directed towards the membrane 19.

The injector is loaded as follows:-

The gas-generating agents are first put into the compartment 12 and the closure 11 is applied and fixed to the wall 4. The compartment 10 is filled with liquid through the opening in the floor of the socket 9 and then the items 17, 18, 19, and 20 are applied to close the opening. Thereafter, the plunger 15 and the items 21 to 27 are applied lightly. In this condition the injector can be stored for an indefinite period. When the injector is installed in a piece of timber the tube 21 is inserted into a pre-bored hole in the timber. Finally, one or more blows are applied to the plunger 15 so

that tube 21 fully penetrates the hole in the timber, the gasket 28 on the flange 22 seals against the timber, the tube 27 ruptures the membrane 19 and penetrates into the insert 18 so as to open flow communication from the compartment 10 to the delivery tube 21 and the sprue or point on the wall 14 ruptures the sachet 13 and thus starts the gas generating reaction for pressurising the liquid. It should be noted that during the time the injector remains in place the spragging washer 24 retains the skirt 23 in its fully depressed position. Furthermore, the insert 20 always finds the lowest point in the compartment 10 so as to remain dipped in the liquid as it is dispensed. Also, because of the provision of a plurality of the filters 5 there is always at least one above the level of the liquid in the compartment 10.

A further embodiment of the injector is shown in Figs 3 and 4. In this embodiment the filters have been removed. One of the gas-generating agents is a liquid contained in the sachet 13 and the other is in the form of solid particles 28. The wall 4 has a nose 29 directed towards the compartment 10. The nose 29 has a central blind bore 30 which itself has a spur 31 covered by an elastic sleeve 32. Behind the nose 29 is a socket 33. Within the wall 4 and covering the part remote from the closure 11 there is a splash guard 34 with fine radial ribbing 35 in contact with or close to the wall 4. The guard 34 has a central spigot 36 inserted in the socket 33. The spigot 36 has an angled bore 37 and communicates with the spaces between the ribbing 35 via spaces between a cruciform ribbing 38 on a bedding surface of the guard 34 from which surface the spigot 36 extends. The plunger 15 has' sprags (not shown) which prevent it from being forced out of the socket 16 once it has been pushed fully home as shown in Fig. 3. The plunger 15 also has an O-ring 15a to seal against gas loss through the portion 11.

The wall 6 defines an angular socket 7 with an integral inner wall 8. The wall 8 itself defines a central socket 9. The insert 18 defines a socket 39 which has a closure 40 presenting a rupturable membrane 41 lying in the floor of the socket 9. A ball 42 is loosely housed in the socket 39. The

tube 17 has at its free end a weighted insert 20. The tube 17 extends with clearance through a grommet 43 which is fitted about the wall 6 and vented at 44 and presents a part-toroidal surface 45 on which the tube 17 can rest without kinking. The insert 20 adopts the lowest position in the compartment 10 regardless of the attitude of the injector.

The tube 21 may be provided with a plug 46 which may be used to rupture a membrane in the bore 47 of the tube 21 and stop up the exit end of the bore 47.

The parts of the injector can lie on a shelf for an indefinite period in the unassembled condition shown in Fig 2. The compartment 10 can be loaded with preservative liquid through socket 9 when this is uppermost and before the items 17, 18, 39, 40, 41, 42 and 20 are applied. When the liquid reaches the level of the opening in the wall 6, the above mentioned items are applied so as to seal the compartment 10. The sachet 13 and particles 28 are also loaded in the compartment 12 and the closure 11 applied and fused. The plunger 15 may then be lightly inserted into the socket 16 and the skirt 23 may be lightly inserted into the socket 7.

When it is desired to use the injector, the plug 46 is either discarded or used as described above and the loosely assembly injector has the tube 21 inserted into a pre-bored hole in the timber to be treated. Then, one or more deliberate blows are applied to the plunger 15 from the rear to that the tube 21 is fully driven into the hole in the timber, the gasket 28 seals either directly or indirectly against the timber, the tube 48 ruptures the membrane 19 and penetrates into the socket 9 so that the free end of the tube 48, which is slotted, forms a throttled passage with the ball 42 in opening flow communication from the compartment 10 to the delivery tube 21. In addition, the sprue or point on the wall portion 14 ruptures the sachet 13 and thus starts the gas generating reaction for pressurising the liquid. It should be noted that during the time the injector remains in place the spragging washer 24 retains the skirt 23 in its fully depressed position. Furthermore, the insert 20 always finds the lowest point in the compartment 10 so as to remain dipped

o

in the liquid as it is dispensed. It should also be noted that if, through vandalism for example, the fused shells 1 and 2 are separated from the delivery tube 21, with 21 remaining in the timber, the tube 48 is withdrawn from the socket 9 so that any pressure in the compartment 10 presses the ball 42 into sealing engagement with a seating surface of the closure 40 and stops further discharge of liquid.

In a modification, the container 13 and particles 28 may be contained in a compartment at the same side of the compartment 10 as the delivery tube 21 so that the shell would be uninterrupted on the opposite side from the tube 21.

A still further embodiment of the injector is shown in Figs 4 and 5. In this embodiment one of the gas-generating agents is a liquid contained in a container 49. The container 49 comprises an annular space 50 defined between radially inner and outer walls 51 and 52. The wall 52 has a ribbed tapering portion to fit and centralise within a correspondingly tapered portion of the wall 4. The space 53 surrounded by the wall 51 is closed by a wall 54 and the spaces 50 and 53 intercommunicate via at least one opening 55 in the wall 51. Extending from the wall 54 on the side thereof remote from the space 53 is a fluted spigot 56. The side of the wall 54 from which extends the spigot 56 is radially ribbed. A flange 57 extends outwardly from the edge of the wall 52 remote from the spigot 56 and a skirt 58 extends from the outer edge of the flange 57 in a direction away from the spigot 56. ^" The skirt 58 serves as a spacer for correct location of the container 49 between the closure 11 and the wall 4. The container 49 has a rupturable closure membrane 59 with a thickened radially outer ring 60 fused to the flange 57. Where the membrane 59 joins the ring 60 there is an annular line of weakness. Centrally of the membrane 59 there is a thickened portion 61 having a shallow socket on the side remote from the spigot 56.

Behind the nose 29 is a socket 33 which receives the spigot 56. The closure 11 has a flexible portion 14 with a thickened central portion 14a which seats in the shallow socket in the portion 61.

The tube 17 extends with clearance through a grommet 43, which has longitudinally-extending ribs on the inner side of its outer cylindrical wall 62 and a projection on its end lip 62a. Thus, when the grommet 43 is fitted about the wall 6 the interior of the grommet 43 is vented to the compartment 10 between the walls 6 and 62. Further venting is provided at 44. The formation of the compartment 10 as defined by 1, 2, 4 and 43 ensures that the insert 20 will always adopt the lowest position in the compartment 10 regardless of the attitude of the injector.

An insert 63 in the tube 21 seals in a socket 64 by means of an 0-ring 65. The tube 21 may be provided with a plug (not shown) which may be used to rupture a membrane in the bore 47 of the tube 21 and thus open side holes 66 in the tube 21, and stop up the exit end of the bore 47.

The parts of the injector can lie on a shelf for an indefinite period in the unassembled condition shown in Fig. 1. The compartment 10 can be loaded with preservative liquid through the socket 9 when this is uppermost and before the items 17, 18, 39, 19, 19a, 22, and 20 are applied. The venting between the interior of the grommet 43 and the compartment 10 prevents air locks. When the liquid reaches the level of the opening in the wall 6, the items mentioned .above are applied so as to seal the compartment 10. The container 49 and particles 28 are also loaded in the compartment 12 and the closure 11 applied and fused. The plunger 15 may then be lightly inserted into the socket 16 and the skirt 23 may be lightly inserted into the socket 37.

When it is desired to use the injector, the plug (not shown) is either discarded or used.as described above and the loosely assembled injector has the tube 21 inserted into a pre-bored hole in the timber to be treated. Then, one or more deliberate blows are applied to the plunger 15 from the rear to that the tube 21 is fully driven into the hole in the timber, the gasket 28 seals either directly or indirectly against the timber, the tube 48 ruptures the membrane 19 and penetrates into the socket 39 so that the free end of the tube 48, which is slotted, forms a throttled passage with the ball

22 in opening flow communication from the compartment 10 to the delivery tube 21. In addition, the nose of the plunger 12 and the thickened portion 14a of the flexible portion 14 of the closure 11 depress the thickened portion 61 of the membrane 59 into the space 53 while the membrane 59 itself ruptures at the thickened ring 60 and is drawn into the space 53. This forcibly injects any liquid in the space 53 into the space 50 through the opening(s) 55, and then into the remainder of the compartment 12 without any hindrance from the membrane 59, so as to react with the particles 28 and generate the pressurized gas. The pressurized gas exits from the compartment 12 between the ribs on the tapering portion of the wall 52 of the container 49, through the flutes in the wall 54 and in the spigot 56, and through the central blind bore 30 and spur 31 passing between the elastic sleeve 32 and the nose 29 into compartment 10.

It should be noted that during the time the injector remains in place the spragging washer 24 retains the skirt 23 in its fully depressed position. Furthermore, the insert 20 always finds the lowest point in the compartment 10 so as to remain dipped in the liquid as it is dispensed.

In a modification, the container 49 and particles 28 may be contained in a compartment at the same side of the compartment 10 as the delivery tube 21 so that the shell would be uninterrupted on the opposite side from the tube 21, and could be manufactured in one piece without the fused rims 3 by the process of blow moulding. A smaller joint would.be necessary around the front or said same side of the compartment 10 to incorporate the subassembly of working components into an opening of the blow moulded shell.

Referring now to Figs 6-10, a preservative jacket comprises an outer or backing layer 67 of impervious flexible material, preferably opaque, and an inner layer 68 of pervious material which may for example be a woven fabric or a needle- felt. An absorbent material 69 is held between the layers 67 and 68 and this may be a mat or flakes which dispays a mechanical resistance to damage. Soft wood shavings or spun bonded fibres are particularly suitable. One convenient form

of the jacket comprises the impervious backing layers, a sheet of pervious material wider than the backing layer laid thereover, with the excess margins of the sheet extending beyond both edges of the backing layer, a further layer identical with the backing layer laid over the sheet and in register with the backing layer. The absorbent material is laid on the further layer, and the excess margins are folded over and onto the absorbent material. Thereafter, the layers are welded or stitched together at the mutually overlying three edges of the folded-over excess margins of the sheet of pervious material and along the edges of the jacket.

A liquid distribution collar 70 which may be formed of a sintered material is set into the layers to permit liquid to be injected into the absorbent material 69. The collar 70 has a central opening 71 for the insertion of a fluid injector, as described later. Leading from the opening 71 in the collar 70 into the absorbent material 69 are radiating holes 72 or other passages.

The jacket is shown fitted on a timber pole in Figs 9 and 10. In Fig 9, the right-hand injector A is shown screwed directly through the jacket and into a bore 73 in the pole so as to inject liquid preservative into the bore 73 which leads to the pole core, without such liquid entering the absorbent material 69.

However, the left-hand injector B while being screwed into a bore 74 in the pole, is blocked from injecting liquid preservative into the bore 74. Instead, the liquid..is injected, via the holes 72 in the collar 70, into the absorbent material 69. Thus, as shown in Fig 9, two different treatments can be performed simultaneously on the pole core and pole surface. It is important to note that with the present invention an organic liquid preservative can be injected into an otherwise inert absorbent material or water can be injected to activate dry crystals or powder already in the absorbent material. For convenience the bores 73, 74 comprise portions of a single through-bore in the pole. Referring, again to Fig 9, an extra collar 75 in the jacket,

may provide access to an oblique, inspection and/or refill bore 76 in the pole leading to the through-bore 73/74. One or more collars 70 may be added either during manufacture of the jacket or alternatively at the pole site by blanking a disc from the jacket, inserting the collar 70 and overlying the disc with a self-adhesive gasket to prevent leakage. The gasket is bonded to the outer layer 67. The gasket can be pre-drilled in order to allow an injector B to be fitted to the pole. Alternatively, a line of weakness may be provided in the gasket allowing the tube 21 of the injector to rupture the gasket upon insertion into the bore 73.