Manchette Tube System - An Overview

Components in a working
Manchette tube system:

A) The Manchette tube, B) Couplings, C) Tips & Caps,
D) Packers, E) Packer Rod ,
F) Connecting Valve, and G) Grout Pump.

A Manchette tube is a PVC or metal pipe in which rubber sleeves cover holes that are drilled in the pipe at specific intervals. The tubes are inserted into holes that have been bored into the "work area" (soil, rock, concrete, etc.) known as the "grout zone". Grout is pumped to a packer that has been slid into the tube. Seals on the packer force the grout thru the holes in the tube, past the flexible rubber sleeve, and into the grout zone to help stabilize and/or seal it. Following is a more detailed explanation of the Manchette tube system and how it works.

A) The Manchette Tube
There are three basic categories of tubes: 1) Standard PVC Tube, 2) Recessed Rubber PVC Tube, 3) Metal Tube.
Common among the tubes are that at every 15 inches along its length, four holes are drilled around its circumference. The holes are covered by a flexible rubber sleeve which allows the grout to flow out into the surrounding environment and prevents it from flowing back into the tube once pumping has stopped. Rubber elements are made from a special compound which resists changes in durometer and extensibility due to UV and temperature. All rubbers are held in place with a light adhesive and are taped down at both ends with electrical tape. Custom lengths of tubing can be assembled via couplings.


Raised Rubber Tube

This tube is constructed of schedule 40 or greater PVC pipe with diameters of 1", 1.5" & 2" and lengths of 5 or 10 feet. The rubber sleeve is slid over, and affixed to, the outer surface of the pipe, thus causing the outer surface of the sleeve to be "raised" above the pipe surface. The ends are straight cut and extended lengths are created with couplings that slide over the outer diameter of the pipe.

Recessed Rubber Tube
This tube is also constructed of schedule 40 or greater PVC pipe. The rubber sleeve covering the grout exit holes sits in a recessed groove in the PVC, made by removing a specified amount of the pipe wall on a lathe. This causes the exterior surface of the rubber sleeve to be flush with the exterior surface of the PVC pipe. This is useful when sliding the Manchette tube along a horizontally bored hole as it helps protect the rubber sleeve against damage and prevents it from "catching" on anything as it slides into the hole. The ends of the pipe are machined on a lathe creating a "female" and "male" end. This allows extended lengths to be created by simply gluing and sliding a male end of one pipe to the female end of another. The effect of all this is that these Manchette tubes are flush on both the inside and outside.

Metal Tube

This tube is similar to the other two as far as grout holes and sleeves except, as it's name implies, it's constructed of steel. It has a raised steel ridge on either side of the rubber sleeve. This is used in situations similar to the Recessed Sleeve PVC tube but is much stronger and offers more protection of the rubber sleeve via the raised steel ridges. It comes in diameters of 1.5" and 2", a length of 26" and a rubber spacing of 14".

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B) Tube Couplings
Tube couplings, as you might guess, connect lengths of Manchette tubes to create overall longer tubes. There are five basic types: 1) Center Stop, 2) Smoothbore, 3) Heavy Duty, 4) Extended Length, and 5) Metal.

Center Stop Coupling
This coupling, made of PVC, connects lengths of "Recessed Rubber" Manchette tubes. It has a small internal ridge, or stop, midway between the ends of the coupling. This stop makes it easier to splice two lengths of pipe in that you simply apply glue and push the two lengths of pipe into the coupling until they both "seat" against the stop, automatically centering the coupling between the two pipes. Manchette tubes connected in this manner must use an "expandable" type of packer as the coupling leaves the two pipes with their ends slightly separated (the width of the internal stop). Packers that have compressed type seals will "catch" on this "space" or "groove". These different types of packers will be discussed later.

Smoothbore Coupling
This coupling, made of PVC, connects lengths of "Raised Rubber" Manchette tubes but has no center stop. This coupling allows the ends of the two adjoining pipes to "butt-up" against one another, thus creating a smooth "catch-free" bore. This type of coupling can use either a compressed seal packer or an expandable seal packer.


Heavy Duty Coupling
This coupling, made of heavy gauge PVC, connects lengths of "Raised Rubber" Manchette tubes and has no center ridge, thus creating a smooth "catch-free" bore. It also has fine internal serrations that hold glue, thus making for a stronger bond.


Extended Length Coupling
These are just like the other couplings except they are
approximately 75% longer.


Steel Coupling
Metal Manchette tubes are threaded on either end and are joined via a threaded metal coupling. Steel couplings and tubes can only be used with an expandable type packer.

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C) Tips and Caps
Tips are cone shaped and made of plastic. They go on the bottom or "leading" end of the Manchette tube. The pointed bottom tip facilitates the insertion of the tube into the bored hole and prevents foreign matter from entering the tube. A cap can be placed on the top or "trailing" end of the tube to prevent foreign matter from entering the tube before grout is pumped or between multiple applications of grout.

D) Packers
The Packer is the device through which grout is pumped into, and forced through, the holes in the Manchette tube. There are two broad categories of Packers: 1. Inflatable Seal Packers, and 2. Sliding Seal Packers.

The two work in similar fashion; they are lowered or pushed (horizontal tube) into the Manchette tube until the packer is halfway past a set of the holes drilled into the tube. Grout is pumped into the top of the packer via a connecting hose (packer rod) and grout pump. The grout flows through the center of the top half of the packer and exits at openings around the middle of the packer which is approximately where the holes in the Manchette tube are. Seals at the top and bottom of the packer prevent the grout from simply filling the tube and pouring out the top of the tube. With no where else to go, the grout is forced thru the holes in the Manchette tube, past the flexible rubber sleeve into the surrounding environment (grout zone). When the desired amount of grout has been pumped at that particular level, the packer is slid to straddle the next set of holes and the process continues. Following is a more detailed look at the different packers.

Inflatable Seal Packer

As the name implies, this type of packer has expanding rubber seals at either end. Besides the grout hose, a second, smaller hose is connected to the top of the packer via which air or a liquid is pumped into the seals (
with most people preferring hydraulic inflation for speed and control), thus expanding the seal tight against the walls of the Manchette tube. After the grout is pumped at that level, they are deflated in order to slide the packer to the next set of holes. There are two types of inflatable seals:1. single chamber, and 2. multiple chamber, both of which are capable of 1,500 psi working inflation pressures. The multi-chamber type is modular, with exchangeable rubber elements to change pipe sizes. The modular rubber elements have steel rings imbedded inside the rubber which create a multiple hourglass shape when inflated. Both types can be either single element or two element (straddle) devices and can have varied straddle distances (by changing out the center section) for simultaneous multi-port injection. The single chamber type has a greater expansion range and thus, the advantage of being able to seal a greater range of tube diameters with just one size seal.

Sliding Seal Packer

The seals on this type packer are slightly larger than the Manchette tube itself and thus fit tightly against the tube walls when the packer is inserted into the tube. There are three types of sliding seals: 1. o-ring, 2. leather cup, and 3. poly-cup.

Mechanical Packers

A mechanical packer is constructed of a short length of pipe with one rubber seal around it. It normally does not use a Manchette tube but one can be connected if necessary. Instead, a hole, slightly larger than the packer, is bored into the grout zone (such as a concrete wall), and the packer is inserted directly into this hole. A threaded screw, on top of the seal, is then turned against the rubber seal, compressing it and causing it to expand tightly against the walls of the bored hole. Grout is then pumped thru the packer and out the far end into the grout zone to be stabilized/sealed.

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E) Packer Rod
The packer rod is a tough but flexible plastic hose through which grout is pumped to the packer. Packer Rod comes in bulk rolls which are cut to the desired length. A threading kit allows the user to put threads on each end of the cut hose to which couplings are then affixed. These couplings allow the hose to be attached to the connecting valve on one end and the packer on the other end.

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F) Connecting Valve
The connecting valve controls the flow of grout into and out of the mechanical packer. There are two types: 1. Cone Valve, and 2. Ball Valve. The Cone Valve (left photo) can be quickly disassembled and cleaned should grout set up in it. Please see our separate section on grout pumps for more detailed information on pumps and connecting valves.

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G) Grout Pump
The grout pump does just that, pumps grout through the connecting hose to the packer inserted in the Manchette tube. Please see our separate section on grout pumps for more detailed information on pumps and connecting valves.

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