GB2282084A

GB2282084A - Liquid Injector

Info

Publication number: GB2282084A
Application number: GB9319665A
Authority: GB
Inventors: David Moore
Original assignee: REMTOX CHEMICALS Ltd
Current assignee: REMTOX CHEMICALS Ltd
Priority date: 1993-09-23
Filing date: 1993-09-23
Publication date: 1995-03-29
Also published as: GB9319665D0

Abstract

A liquid injector (1) for injecting damp proofing liquid into masonry comprises an injector rod (2) provided with a diffuser (16). In use the injector rod (2) is inserted into a hole drilled in the masonry and a seal (5) is then formed upstream of the diffuser (16). Damp proofing liquid is pumped into the diffuser (16) and passes outwardly to the masonry along the length of the diffuser (16). <IMAGE>

Description

LIQUID INJECTOR This invention relates to a liquid injector, more particularly, but not exclusively, for injecting damp proofing liquid into masonry. It also relates to a liquid injection apparatus including such a liquid injector.

One common method to counteract rising damp in buildings is to inject damp proofing liquid, for example silicon, into the masonry to form a damp proof course.

Typically, this is effected by drilling a plurality of 75mm deep holes at about 115mm centres into the mortar between the bricks and/or blocks. A liquid injector is then inserted into the holes and a seal expanded circumjacent the nozzle. Damp proofing liquid is then pumped into the holes and permeates the adjacent masonry.

For many purposes it is perfectly acceptable to continue pumping the damp proofing liquid until it can be seen oozing out of the surface of the brickwork, thus indicating a complete treatment. However, this can be wasteful. Furthermore, for certain applications, it is not acceptable to allow the liquid to permeate to the surface, for example when treating the inner skin of a domestic wall where staining the plaster would be unacceptable. In such cases it is usual to inject a predetermined amount of damp proofing liquid into each hole.

Whilst this approach should be quite acceptable, we have found that the results are not always entirely satisfactory. We believe this may be due to local fractures in the masonry which absorb a major portion of the available damp proofing liquid leaving other areas untreated and thus provide a bridge for the damp.

In order to help reduce this problem, the present invention provides a liquid injector incorporating a diffuser.

In one embodiment of the invention the diffuser comprises a cylinder of porous material of generally circular cross-section which is mounted on the free end of an injection rod.

Preferably, said injection rod is provided with a coupling to which said diffuser is attached and the outer diameter of the diffuser is less than the diameter of the coupling.

Advantageously, the diffuser is provided with an axially extending channel to facilitate the distribution of liquid therethrough.

In another embodiment of the invention a liquid injector (which is better shown in Figure 2 of UK-A2 226 301) is designed to simultaneously treat the inner and outer skins of a cavity wall. In particular, the liquid injector comprises an injector rod including a central tube which is arranged to carry liquid to the inner skin and an outer tube which is provided with radially positioned outlet holes arranged to dispense liquid to the outer skin. In such an embodiment a diffuser in the form of a sleeve of porous material may be placed over the outer tube with a separate diffuser optionally being mounted on the tip to service the inner skin.

The present invention also provides a liquid injection apparatus comprising a liquid injector in accordance with the invention and a metering apparatus for passing controlled quantities of liquid therethrough.

Preferably the metering apparatus comprises a metering cylinder having a piston slidably mounted therein and a rod connected to said piston and extending outwardly from said metering cylinder, a supply tube, a pipe connecting said supply tube to one end of said metering cylinder, and a three-way valve communicating with said supply tube, said other end of said metering cylinder, and a tube connectable to said liquid injector.

For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic section through a known liquid injector; Figure 2 is a schematic section through a liquid injector in accordance with the invention; Figure 3 is a schematic section through a metering device for metering the flow of liquid through the liquid injector shown in Fig. 2, the metering device being shown in a first position; Figure 4 is a schematic section showing the metering device of Figure 3 in a second position; and Figure 5 is a schematic section showing the metering device of Figure 3 in a third position.

Referring to Figure 1 of the drawings, there is shown a know liquid injector which is generally identified by reference numeral 1. The liquid injector 1 comprises an injector rod 2 which extends between a female coupling 3 and a tip 4.

A seal 5, formed by a short length of plastic hose, is mounted on the injector rod 2 between the tip 4 and a cylinder 6.

An end cap 7 having a radially extending wall 8 and a cylindrical wall 9 is slidably mounted on the injector rod 2. The cylindrical wall 9 is spaced from a course thread 10 formed on a head member 11 surrounding the injector rod 2.

A thrust member 12 having a handle 13 is threadedly mounted on the head member 11.

In use, a hole of marginally greater diameter than the tip 4 is drilled into the masonry to be treated. The hole will typically be about 75mm in depth in a standard lOOmm skin. The liquid injector 1, which is coupled to a source of damp proofing liquid, is then inserted into the hole until the tip 4 engages the end of the hole.

The handle 13 is then turned clockwise so that the thrust member 12 bears against and displaces the end cap 7 towards the tip 4. This in turn displaces the cylinder 6 towards the tip 4 and causes the seal 5 to bulge outwardly thereby forming a reasonable seal against the radial wall of the hole.

Damp proofing liquid is then pumped through the injector rod 2 and soaks through the masonry. At the desired time the pump is switched off. The thrust member 12 is rotated anti-clockwise by the handle 13 thereby releasing the seal 5 and allowing the liquid injector to be withdrawn.

It will be appreciated that all the damp proofing liquid enters the masonry through the hole 14 in the tip 4.

As discussed previously, when a metered amount of liquid is to be injected into the hole problems can arise. In particular, if the masonry contains a fissure it is possible for a large portion of the damp proofing liquid to enter the fissure and for parts of the masonry to be untreated.

In order to help reduce this problem, and as shown in Figure 2, the tip 4 is replaced by a female coupling 15 into which is screwed a diffuser in the form of a disposable porous member 16 which is approximately 75mm in length. A channel 17 extends along part of the length of the porous member 16.

In use, when liquid is pumped through the injector rod 2 it passes into the channel 17 and permeates radially outwardly so that the liquid is distributed circumjacent the porous member 16 and from the end face thereof. If desired, the end face may be covered with an impermeable end cap to ensure that all the available liquid is applied radially outwardly.

The porous member 16 may be made of a variety of porous materials, for example ceramics and/or plastics.

A presently preferred material is VYON "HP" 3.2mm sold by Porvair Plc of King's Lynn, Norfolk, England. It should be noted that a spray bar formed by drilling a plurality of holes in a brass tube is unsuitable since the holes tend to clog, the brass tubes tend to break and are expensive.

Figures 3, 4 and 5 show a metering apparatus for injecting a predetermined amount of liquid into a liquid injector.

The metering apparatus, which is generally identified by reference numeral 18, comprises a flexible supply tube 19 which is connected to a metering cylinder 20 via a pipe 21 and via a three-way valve 22 and pipe 23.

A piston 24 is slidably mounted in the metering cylinder 20 and is attached to a rod 25.

At the start of an injection operation the threeway valve 22 is in the position shown in Figure 3.

Liquid is supplied to the flexible supply tube 19 from a pump (not shown) at a pressure up to about 14 bar g. The liquid enters the cylinder 20 via pipe 21 and displaces the piston 24 to the right as shown.

When the three-way valve 22 is moved to the position shown in Figure 4, the liquid enters the cylinder 20 through pipe 23 and displaces the piston 24 to the left since the cross-sectional area of the front face 26 of the piston 24 is greater than the annular area 27 surrounding the plunger 25.

When the metering cylinder 20 is full, indicated by a mark 28 on the plunger 25, the three-way valve 22 is moved to the position shown in Figure 5. In this position the liquid from the flexible supply tube 19 flows through the pipe 21 displacing the piston 24 to the position shown in the Figure and dispensing a metered quantity of liquid to male coupling 29 which is connected to the liquid injector.

Whilst the liquid injector described with reference to Figure 2 is primarily included for the injection of damp proofing liquid into masonry it may also be used for the injection of remedial liquid into timber, for example for treating woodworm, dry rot and wet rot. It may also be used for impregnating sound timber with preservatives.

Claims

Claims:

1. A liquid injector incorporating a diffuser.

2. A liquid injector as claimed in Claim 1, wherein said diffuser comprises a cylinder of porous material of generally circular cross-section which is mounted on the free end of an injector rod.

3. A liquid injector as claimed in Claim 2, wherein said injector rod is provided with a coupling to which said diffuser is attached and the diameter of said diffuser is less than the diameter of said coupling.

4. A liquid injector as claimed in Claim 1, 2 or 3, wherein said diffuser is provided with an axially extending channel to facilitate the distribution of liquid therethrough.

5. A liquid injector as claimed in any preceding Claim, wherein said liquid injector comprises an injector rod including an inner tube for carrying liquid to an inner skin of a cavity wall, an outer tube circumjacent said inner tube and having at least one outlet for connecting liquid to an outer skin of a cavity wall, and wherein said diffuser comprises a sleeve circumjacent said outer tube.

6. A liquid injector substantially as hereinbefore described, with reference to and as shown in Figure 2 of the accompanying drawings.

7. A liquid injection apparatus comprising a liquid injector and a metering apparatus for passing controlled quantities of liquid therethrough.

8. A liquid injection apparatus as claimed in Claim 7, wherein said metering apparatus comprises a metering cylinder having a piston slidably mounted therein and a plunger connected to said piston and extending outwardly from said metering cylinder, a supply tube, a pipe connecting said supply tube to one end of said measuring cylinder, and a three-way valve communicating with said supply tube, said other end of said metering cylinder, and a tube connectable to said liquid injector.