Patent Description:
The most common construction method for ground floors in new build residential dwellings is based on a beam and block methodology. A beam and block floor is suspended above the ground with a series of concrete inverted 'T' shaped beams built from the masonry walls with blockwork supported on and placed between the beams to create a floor system. This approach to floor construction was developed over <NUM> years ago and accounts for approximately <NUM>% of all ground floor construction in the UK new build residential market.

Since the early <NUM>, UK Building Regulations have required construction contractors to insulate the fabric of a building to improve the energy efficiency of the building and reduce the buildings impact on CO2 emissions. The requirement to improve the energy efficiency has led to a need for insulation to be included within the floor design.

In a beam and block floor, there are currently two ways that this can be done;.

Over time as the need to reduce CO2 emissions has become more apparent and Building Regulations have become more onerous, requiring increasingly thick layers of insulation above the beam and block system to comply with Regulations. As the floor becomes thicker to allow for more insulation, the building also becomes taller. This leads to additional costs and consumption of further materials damaging the environment further. The trend for Regulations to become more onerous will continue creating a growing problem of unnecessary material consumption (by building taller buildings).

Furthermore, in the past, floor timbers were often laid directly on top of the ground but this inevitably led to damp and rot in the timbers. To correct this suspended timber floors were introduced that raised the timbers above the soil and created a ventilated void below the floor construction, preventing the timbers from touching the damp ground and providing ventilation to reduce the risk of condensation. However, an uninsulated suspended timber floor can lose more heat than the walls or the loft area. Yet this is an area that is very often overlooked when it comes to upgrading older properties, due to the difficulty in insulating this void without lifting the existing timber floor.

It is known to introduce expanded polystyrene (EPS) bead insulation, with or without a bonding adhesive, into cavity wall constructions by providing a series of boreholes through one skin of the wall (typically the outer skin) and using bead injection guns fitted with nozzles that fit into the bore holes. The EPS bead is then injected into the cavity wall using a compressed air system. The flow of compressed air forces the beads through the bore hole and causes the bead to be pushed against the opposite skin of the wall, where the bead rebounds off and falls down to fill the vertical space beneath. The injection system has been designed to use a combination of compressed air and gravity to ensure that the injected beads fill the vertical space correctly. These systems are often referred to as "blown bead" cavity wall insulation. Typically a bonding agent, such as a liquid adhesive, is added to the beads so that they become bonded together once settled within the cavity. The bonding agent is typically mixed with the beads within the bead injection gun. <CIT> discloses a known bead injection gun for injecting beads and adhesive into a wall cavity showing the features of the preamble of claim <NUM>.

However, known blown bead cavity wall insulation systems are not suitable for filling a horizontal space, such as an underfloor void, because the effects of gravity leading to an acceptable standard of fill within a vertical space (e.g. a cavity wall) no longer have a positive effect on this installation technique when applied to a horizontal space. As a result, the application of injected beads has not been expanded for use in floor voids in masonry construction. It would be desirable to mitigate this disadvantage.

According to the present invention there is provided an apparatus for injecting particulate insulant material into an underfloor void as claimed in claim <NUM>.

Preferably said bonding agent is supplied to the bonding agent inlet from a pressurised reservoir via a bonding agent flow control valve.

Preferably a source of compressed air is provided communicating with the compressed air inlet via a flexible supply hose, the flow of air to said compressed air inlet being controlled by an air flow control valve.

Said bonding agent flow control valve and said air flow control valve are preferably provided on the dispensing head to facilitate control of the injection of the particulate insulant material into said underfloor void.

The apparatus may further comprise comprising a particulate insulant material reservoir containing a supply of particulate insulant material, said particulate insulant material reservoir communicating with the particulate insulant material inlet via a flexible supply hose, the particulate insulant material being entrained from the particulate insulant material reservoir into the mixing chamber by the compressed air entering the mixing chamber from the compressed air inlet.

An adjustable depth gauge or stop may be mounted on the dispensing head for limiting the insertion depth of the outlet nozzle through a hole in a floor leading into an underfloor void.

The particulate insulant material inlet may be angled towards the outlet nozzle as it enters the mixing chamber. The particulate insulant material inlet may extend at an acute angle to the compressed air inlet as it enters the mixing chamber. Preferably the bonding agent inlet opens into said first side wall of the mixing chamber, adjacent the particulate insulant material inlet. The bonding agent inlet preferably opens into said first side wall of the mixing chamber between the particulate insulant material inlet and the front wall of the mixing chamber, such that the bonding agent is delivered into the mixing chamber downstream of the particulate insulant material.

An apparatus for injecting particulate insulant material into an underfloor void will now be described, by way of example only, with reference to the accompanying drawings in which:
<FIG> is a schematic view of an apparatus for injecting particulate insulant material into an underfloor void in accordance with an embodiment of the present invention.

As illustrated in <FIG>, an apparatus for injecting particulate insulant material, in particular EPS beads, into an underfloor void, preferably beneath a beam and block floor, in accordance with an embodiment of the present invention comprises a dispensing head in the form of an injection gun <NUM> having a hollow cuboid body defining a mixing chamber <NUM>, an outlet nozzle <NUM> extending from said mixing chamber <NUM> adapted to be inserted into a bore hole for dispensing EPS bead into an underfloor void, a compressed air inlet <NUM> being adapted to supply compressed air into said mixing chamber <NUM> and a particulate insulant material inlet <NUM> adapted to supply a particulate insulant material into the mixing chamber <NUM>. The compressed air inlet <NUM> is axially aligned with said outlet nozzle <NUM>.

The compressed air inlet <NUM> communicates with a source of compressed air <NUM> via a flexible air line <NUM>, a compressed air flow control valve <NUM> being provided on the body of the injection gun <NUM>.

A particulate insulant material reservoir <NUM> containing a supply of particulate insulant material is provided, the particulate insulant material reservoir <NUM> communicating with the particulate insulant material inlet <NUM> via a flexible supply hose <NUM>.

The compressed air inlet <NUM> opens into a rear wall of the mixing chamber <NUM> and the outlet nozzle <NUM> extending from a front wall of the mixing chamber <NUM>, opposite the rear wall. The particulate insulant material inlet <NUM> opens into the rear wall or in an adjacent first side wall of the mixing chamber <NUM>. The particulate insulant material inlet <NUM> is angled towards the outlet nozzle <NUM> as it enters the mixing chamber <NUM> and extends at an acute angle to the compressed air inlet <NUM>. This causes the particulate insulant material to be entrained from the particulate insulant material reservoir <NUM> into the mixing chamber <NUM> by the compressed air entering the mixing chamber <NUM> from the compressed air inlet <NUM>.

A bonding agent inlet <NUM> is provided for delivering a bonding agent into the mixing chamber <NUM> to be mixed with the particulate insulant material before it is dispensed from the outlet nozzle <NUM>. A bonding agent (e.g. suitable liquid adhesive) is supplied to the bonding agent inlet <NUM> from a pressurised reservoir <NUM> via a flexible supply line <NUM>. The flow of bonding agent into the mixing chamber <NUM>, which may be via a suitable spray nozzle to disperse the bonding agent into the particulate insulant material, is controlled by a bonding agent flow control valve <NUM> provided on the body of the dispensing gun <NUM>.

A distal end portion <NUM> of the outlet nozzles diverges outwardly, as described below, in order to ensure that the particulate insulant material spreads out throughout the underfloor void.

The apparatus may be used for the injection of EPS bead insulation, preferably with the addition of a bonding agent, into an underfloor void. The air line <NUM> may be connected the injection gun <NUM> at the rear, by means of <NUM> flexible hosing. The bead supply hose <NUM> may be comprised of <NUM> transfer pipe connected to the bead reservoir <NUM>. The bonding agent line <NUM> connected to the bonding agent inlet <NUM> on the side of the gun <NUM> may comprise <NUM> flexible hose. The bonding agent inlet <NUM> incorporates a spray nozzle to disperse the bonding agent into the mixing chamber <NUM>.

The apparatus allows for the homogenous mixture of EPS and adhesive of the correct viscosity to enable the mixture to accumulate in the desired manner on a base of the underfloor void. The compressed air entering the underfloor void then forces this mixture to move concentrically into the final desired position eventually filling the underfloor void.

Air pressure regulators may located at a control board. These may be used in association with the control valves <NUM>,<NUM> of the bonding agent inlet <NUM> and compressed air inlet <NUM> on the injection gun <NUM> to control the pressure in each of the bonding agent line <NUM> and compressed air line <NUM>, providing enhanced control over the system.

The injection gun <NUM> may be cuboid in design, defining a hollow cuboid mixing chamber <NUM> with specific inlets for a particulate insulant material, more preferably EPS beads, a bonding agent and compressed air, along with the specifically designed outlet nozzle. The cuboid design of the mixing chamber <NUM> allows for the complete mixture of insulant material and bonding agent within the mixing chamber <NUM>, along with providing a low flow resistance pathway towards the outlet nozzle <NUM> and thereby into the horizontal underfloor void to be filled.

In the embodiment shown, the outer portion <NUM> of the outlet nozzle <NUM> of the injection gun <NUM> diverges from <NUM> to <NUM> in diameter to facilitate the spread of the injected material throughout the horizontal void.

An adjustable depth stop bar <NUM> is preferably mounted on the injection gun body <NUM> via an adjustable mounting clamp <NUM>, such that the stop bar <NUM> extends adjacent and parallel to the outlet nozzle <NUM> to abut the upper surface of the block adjacent the bore hole into which the outlet nozzle <NUM> is to be inserted, allowing the user to ensure the outer end of the outlet nozzle <NUM> is at the correct depth when inserted into a bore hole through the blockwork to optimise the filling process.

The diverging outer portion <NUM> of the outlet nozzle <NUM> encourages the bead to spread as wide as possible upon exit from the outlet nozzle into the horizontal underfloor void.

The length of the outlet nozzle <NUM> is selected to be shorter than the bore hole depth (i.e. block thickness). The shorter length of nozzle <NUM> combined with the diverging outer portion <NUM> of the outlet nozzle <NUM> and the use of the depth stop bar <NUM> ensures that the nozzle insertion depth remains less than the depth of the bore hole and ensures even spreading of the bead throughout the underfloor void.

While the above embodiment of the invention has been described in relation to the injection of EPS beads, with or without a bonding agent, into an underfloor void, it is envisaged that the method and apparatus of the present invention may be used with numerous other forms of particulate insulant material, such as other polymeric bead materials, mineral wool, glass fibres, cellulose fibres, vermiculite, perlite.

Injecting particulate insulant material into an underfloor void using a method and apparatus in accordance with the present invention reduces the overall material consumption in the build, improves the speed of construction (a significant problem in UK given our current shortage of housing), reduces the financial cost of delivery of a block and beam floor system and contributes towards improving the thermal performance of the whole building. It may also future proof against Building regulations changes because it is possible to create a larger void beneath the floor by excavating additional earth from beneath the floor which can then be filled with a greater volume of particulate insulant material.

Claim 1:
An apparatus for injecting particulate insulant material into an underfloor void comprising a dispensing head (<NUM>) having a mixing chamber (<NUM>), an outlet nozzle (<NUM>), a compressed air inlet (<NUM>) and a particulate insulant material inlet (<NUM>), wherein the compressed air inlet (<NUM>) is axially aligned with said outlet nozzle (<NUM>), and wherein a bonding agent inlet (<NUM>) is provided for delivering a bonding agent into the mixing chamber (<NUM>) to be mixed with the particulate insulant material before it is dispensed from the outlet nozzle (<NUM>), characterised in that the mixing chamber (<NUM>) is cuboid in shape, the compressed air inlet (<NUM>) opening into a rear wall of the mixing chamber and the outlet nozzle (<NUM>) extending from a front wall of the mixing chamber (<NUM>) opposite the rear wall, the particulate insulant material inlet (<NUM>) opening into said rear wall or in a first side wall of the mixing chamber (<NUM>) adjacent the rear wall, wherein a distal end portion (<NUM>) of the outlet nozzle (<NUM>) diverges outwardly in order to ensure that the particulate insulant material spreads out throughout the underfloor void.