EP3097982B1

EP3097982B1 - An apparatus and a method for dispensing bead insulation into cavity walls for providing insulation between two skins of the walls

Info

Publication number: EP3097982B1
Application number: EP16170865.6A
Authority: EP
Inventors: Stefan Jozef Maria NOOIJENS
Original assignee: S Nooijens Beheer BV
Current assignee: S Nooijens Beheer BV
Priority date: 2015-05-29
Filing date: 2016-05-23
Publication date: 2019-07-24
Anticipated expiration: 2036-05-23
Also published as: NL2014884B1; NL2014884A; DK3097982T3; EP3097982A1

Description

The present invention relates to an apparatus and a method for dispensing bead insulation into cavity walls for providing insulation between two skins of the walls, the apparatus comprising:

a dispensing head arranged for dispensing bounded bead insulation, comprising dry bead insulation and adhesive fluid, into said cavity walls;
a bead container connected to said dispensing head via a bead supply pipe, and arranged for storing said dry bead insulation;
bead transportation means arranged for transporting said dry bead insulation from said bead container to said dispensing head via said bead supply pipe;
an adhesive container connected to said dispensing head via an adhesive supply pipe, and arranged for storing said adhesive fluid;
adhesive fluid transportation means arranged for transporting said adhesive fluid to said dispensing head via said adhesive supply pipe,

Cavity walls typically consist of two skins separated by a hollow space, i.e. cavity. The skins are commonly masonry such as brick or concrete block. Masonry is an absorbent material, and therefore will slowly draw rainwater or even humidity into the wall. The cavity serves as a way to drain this water back out through weep holes at the base of the wall system or above windows, but is not necessarily vented. A cavity wall with masonry as both inner and outer skins is more commonly referred to as a double wythe masonry wall.
Apparatuses already exist which are suitable to dispense bounded bead insulation, comprising dry bead insulation and adhesive insulation, into such cavity walls.
Currently, regulations are provided which lay out the specific ratio of the amount of dry bead insulation to the amount of adhesive fluid. As such, before starting the dispensing process, the apparatus needs to be set, and checked, for proper settings of the ratio of transported dry bead insulation to the transported adhesive fluid. The apparatus is typically checked once a day to determine whether the ratio is still correct, i.e. whether the actual provided or dispensed ratio corresponds to the ratio which is set in the apparatus.
The above mentioned regulations also provide for a prescribed method, i.e. calibration process, for checking whether the ratio is correct. That calibration process is as follows.
First, the amount of dry bead insulation per unit of time dispensed by the apparatus is determined. To do so, the dry bead insulation is dispensed, by the apparatus, in a box or crate. The box or crate needs to be completely filled with the dry bead insulation, and the time required for filling the box or crate is to be recorded. The flow rate, or throughput, of the dry bead insulation is then obtained by dividing the volume of the box or crate by the time required for filling it.
Second, the amount of adhesive fluid is determined by providing the adhesive fluid via an injector or the like into a calibrated, transparent, measuring cup. The flow rate, or through put, of the adhesive fluid is then obtained by dividing the amount of adhesive fluid in the measuring cup by the time required for filling it.
The ratio of transported dry bead insulation to the transported adhesive fluid is then obtained by dividing the flow rate of the dry bead insulation by the flow rate of the adhesive fluid.
The above mentioned calibration process assumes that the flow rate of dry bead insulation and the flow rate of adhesive fluid are constant during the process of dispensing bead insulation into cavity walls for providing insulation between two skins of the walls.
It was one of the insights of the inventor that these flow rates may actually vary during the said process due to, for example, the following aspects:

congestions in the bead supply pipe or in the adhesive supply pipe;
changes occurring in the air humidity;
variations occurring in the air supply or variations occurring in the adhesive container pressure, and
abrasion in the dispensing head.

As such, it is an object to provide for an improved apparatus for dispensing bead insulation into cavity walls.
It is a further object to provide for an improved method for dispensing bead insulation into cavity walls.
In a first aspect of the invention, there is provided an apparatus for dispensing bead insulation into cavity walls for providing insulation between two skins of said walls, said apparatus comprising:

a dispensing head arranged for dispensing bounded bead insulation, comprising dry bead insulation and adhesive fluid, into said cavity walls;
a bead container connected to said dispensing head via a bead supply pipe, and arranged for storing said dry bead insulation;
bead transportation means arranged for transporting said dry bead insulation from said bead container to said dispensing head via said bead supply pipe;
an adhesive container connected to said dispensing head via an adhesive supply pipe, and arranged for storing said adhesive fluid;
adhesive fluid transportation means arranged for transporting said adhesive fluid to said dispensing head via said adhesive supply pipe, wherein said apparatus further comprises:
a dry bead flow meter arranged for determining a measure for a flow rate of said transported dry bead insulation, wherein said dry bead flow meter is arranged for determining said measure for said flow rate of said transported dry bead insulation by measuring an under pressure in any of said dispensing head or said bead supply pipe;
an adhesive fluid flow meter arranged for determining a measure for a flow rate of said transported adhesive fluid;
a control unit in electronic communication with said dry bead flow meter and said adhesive fluid flow meter, and arranged for determining and providing a ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures, and wherein:
said control unit comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, and
said control unit is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.

The dispensing head is typically a hand held device, for example a dispensing gun, and is thus to be carried and operated by an operator with one or two hands. A nozzle or the like may be provided at the dispensing head, wherein the nozzle is to be placed inside the hollow space bounded by the two skins of the walls. The dry bead insulation and the adhesive fluid may be mixed together inside a chamber comprised by the dispensing head before the mixture, i.e. the bounded bead insulation, is dispensed.
The bead container connected to said dispensing head via a bead supply pipe. The bead supply pipe may be, for example, a hose, a duct, a tube, a metallic pipe, or the like. The dry bead insulation may comprise beads formed from polystyrene or other thermally insulating material, such as expandable polystyrene comprising an expanding agent, for example, pentane, or foamed plastics particles. According to the present invention, the bead transportation means are arranged for transporting the dry bead insulation from the bead container to the dispensing head via the bead supply pipe. The bead transportation means may, for example, comprise an air compressor for generating an air flow or an air pressure. The bead container may, for example, be pressurized by the air compressor for pushing the dry bead insulation towards the dispensing head. The air compressor may also be used for creating a vacuum at the dispensing head for pulling the dry bead insulation from the bead container to the dispensing head.
The adhesive container is connected to the dispensing head via an adhesive supply pipe, and is arranged for storing the adhesive fluid. The adhesive fluid is typically a liquid, which liquid can be transported by a peristaltic pump or the like to the dispensing head. A gaseous like adhesive fluid can be transported towards the dispensing head via an air flow or the like.
It was the insight of the inventor that known apparatuses for dispensing bead insulation into cavity walls can be improved in case the instantaneous ratio of transported dry bead insulation to transported adhesive fluid is determined and provided.
The instantaneous ratio may be provided, for example, by display means provided in the apparatus, or may be digitally stored in the apparatus such that the values thereof may be checked, or validated, after the dispensing process has been completed. The providing step may therefore be directed to the provisioning of information to the operator of the apparatuses to either determine whether the actual ratio of dry bead insulation to adhesive fluid of the dispensed bounded bead insulation is according to predetermined threshold values, or to validate, after the process has been completed, whether the ratio of the dispensed bounded bead insulation was correct.
To do so, the inventor noted that the apparatus should be equipped with a dry bead flow meter arranged for determining a measure for a flow rate of said transported dry bead insulation and an adhesive fluid flow meter arranged for determining a measure for a flow rate of said transported adhesive fluid.
The control unit, in electronic communication with the dry bead flow meter and the adhesive fluid flow meter, is then able to determine and to provide for the ratio of transported dry bead insulation to transported adhesive fluid based on the determined measures.
The measure for a flow rate, as described above, is considered as any type of measure from which directly, or indirectly, the flow rate can be determined. Examples hereof are as follows. The flow meters may, for example, be suitable to directly determine the flow rate inside the pipes using high frequency electromagnetic fields, or may be arranged for determining the rate at which the dry bead container or the adhesive fluid container is emptied, for example using a height level meter or the like.
Finally, the control unit comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, and said control unit is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid. The advantage hereof is that a predetermined ratio of adhesive to dry bead insulation is obtained.
It was the insight of the inventor that the dry bead flow meter should be arranged for determining said measure for said flow rate of said transported dry bead insulation by measuring an under pressure in any of said dispensing head or said bead supply pipe. The inventor has found that the under pressure is a measure for the actual rate of the transported dry bead insulation.
The control unit comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, and

the control unit is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.

It was the insight of the inventors that, in order to further improve the apparatus, the instantaneous ratio of transported dry bead insulation to transported adhesive fluid may be used for controlling at least one of the adhesive fluid transportation means and the bead transportation means. The controlling aspect is then directed to controlling the flow rate of either the dry bead insulation or the adhesive fluid, or both, such that the instantaneous ratio is compensated.
In a further example, the control unit comprises at least one of a proportional, integral and derivative controller for controlling said at least one of said adhesive fluid transportation means and said bead transportation means.
The advantage hereof is that the implementation of the control unit is made simpler. For example, the inventor noted that a PID controller may be suitable to control the instantaneous ratio of transported dry bead insulation to transported adhesive fluid in the dispensed bounded bead insulation.
In another example, at least one of said adhesive fluid transportation means and said bead transportation means comprises a valve, and wherein said control unit is arranged to control said at least one valve based on said determined ratio and said desired ratio.
The advantage hereof is that the flow rate of either the adhesive fluid or the dry bead insulation, or both, can be controlled in quick manner. Adjusting the flow rate by controlling a pump or a compressor or the like is usually time consuming resulting in a longer delay before the instantaneous ratio in the dispensed bounded bead insulation is compensated.
In a further example, the control unit further comprises flow rate settings for at least one of said transported adhesive fluid and said transported dry bead insulation, and wherein

said control unit is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined measures and said flow rate settings.

It was the insight of the inventor that the flow rate of at least one of the transported adhesive fluid and said transported dry bead insulation depends on the actual application, i.e. the actual construction of the cavity wall to be filled with the insulation material. For example, a cavity wall having a relatively large inner space can be filled relatively quickly, i.e. with relative high flow rates, while a cavity wall having a relatively small inner space should be filled relatively slowly, i.e. with relatively low flow rates.
As such, not only the ratio may be controlled, by the control unit, but also the actual value of the flow rate of one of the transported adhesive fluid and said transported dry bead insulation.
In an example, the dry bead flow meter is arranged for measuring, in said bead supply pipe, said flow rate of said transported dry bead insulation using for example a high frequency electromagnetic sensor. Such types of sensors are specifically developed for measuring the flow rate of solids conveyed in ducts. Different types of sensors exist, each of which suitable for different sizes of solids, for example ranging from 1 nanometre to 3 centimetre. The solids do not need to be conveyed sequentially in order for such a sensor to measure the flow rate. Even the flow rates of solids conveyed in bulk can be measured.
Such sensors are operating according to microwave technology. A measuring field is produced by linking the micro wave together with a metal duct, i.e. the bead supply pipe. The microwave energy is reflected by the solid particles and received by the sensor. These signals are evaluated in frequency and amplitude. The sensors works like a particle counter, which counts the quantity of moving particles per time unit. Due to the selective frequency evaluation, only moving particles are measured and deposits are ignored.
The measure of the flow rate for the dry bead insulation and/or the adhesive fluid may also be accomplished by load cells placed under the bead container and/or the adhesive container. The decrease in the measured load over time is a direct measure for the flow rate of the adhesive fluid and/or the dry bead insulation.
In a further example, the adhesive fluid flow meter is arranged for measuring, in said adhesive fluid pipe, said flow rate of said transported adhesive fluid.
Different types of such flow meters may be suitable for measuring the flow of the adhesive fluid. In an example, the adhesive fluid is provided with an electrically conductive additive, and the flow rate of that additive is determined by an electromagnetic flow sensor, which flow rate is a measure for the flow rate of the adhesive fluid itself.
In another example, the bead transportation means comprise an air compressor, connected to said dispensing head via an air supply pipe, wherein said bead supply pipe and said air supply pipe are arranged such that said dry bead insulation are transported to said dispensing head via a venturi process. This has the effect that the transport of the dry bead insulation to the dispensing head is made simpler.
The apparatus may further comprise a pressure sensor in electronic communication with said control unit, and arranged for measuring a pressure in said air supply pipe.
The valve, as mentioned in an earlier example, may also be comprised in said air supply pipe for (indirectly) controlling said flow rate of said transported dry bead insulation, by controlling the actual flow rate of the airflow.
The valve comprised in the air supply pipe may also be used as an emergency stop, for example whenever the flow rate of the adhesive fluid suddenly drop. The flow rate could suddenly drop when the adhesive container is emptied, i.e. all adhesive fluid is drawn from the adhesive container. In such a way, the valve may be activated to fully stop the transport of the dry bead insulation to the dispensing head.
The apparatus may further comprise a ball valve comprised in said air supply pipe for manually controlling a flow rate of air through said air supply pipe. Such a ball valve may be used to activate, or deactivate, the apparatus. Once the operator decides to active the air flow, and thus also the provisioning of the dry bead insulation to the dispensing head, the control unit will automatically make sure that the correct amount of adhesive fluid is being transported to the dispensing head such that the ratio dry bead insulation to adhesive fluid is according to a predetermined threshold.
In another example, the apparatus comprises communication means arranged for communicating, over a public communication network, to a mobile device connected to said public network, said ratio of transported dry bead insulation to transported adhesive fluid for providing a user of said mobile device insight in said ratio. The public communication network may be the public internet.
In a further example, said apparatus further comprises a flow meter for measuring an air flow in said air supply pipe for determining whether said dry bead insulation are being transported.
The advantage hereof is that the apparatus may be stopped, or halted, in case it is detected that no dry bead insulation is actually being transported.
In a detailed example hereof, the flow meter comprises a reed switch for determining whether said dry bead insulation are being transported. A reed switch is an electrical switch which is operated by an applied magnetic field. It comprises a pair of contacts on ferrous metal reeds in a sealed glass casing. The contacts may be normally open, closing when a magnetic field is present, or normally closed and opening when a magnetic field is applied. A magnetic or metallic ball may be present inside the casing, wherein the air flow moves the magnetic or metallic ball inside the casing in between, or out from, the pair of contacts. This is thus an indication that an air flow is actually present in the air supply pipe.
Another advantage is that in such a case no contact is required on the dispensing head for detecting whether the beads are being transported. As such, long cables between the dispensing head and a control unit are avoided.
In another example, said apparatus further comprises a pressure sensor in electronic communication with said control unit, and arranged for measuring a pressure in said air supply pipe.
In a further example, said apparatus further comprises a check valve comprised in said adhesive supply pipe for preventing transported adhesive to said dispensing head to return into said adhesive supply pipe.
The advantage hereof is that, for example, whenever a person suddenly moves the dispensing head in vertical direction, the adhesive is not able to flow back into the adhesive supply pipe as this is prevented by the check valve.
In an even further example, said adhesive fluid transportation means comprise a peristaltic pump in communication with said control unit and arranged for pumping said adhesive fluid.
The adhesive fluid transportation means may also comprise two valves, a first valve for building up a pressure in the an adhesive container and a second valve for lowering the build up pressure in the adhesive container. In such a way the adhesive is pushed, under pressure, towards the dispensing head. The amount of adhesive is then to be controlled using the first and the second valve, thereby adjusting the pressure inside the adhesive container.
In a second aspect of the invention, there is provided a method for dispensing bead insulation into cavity walls for providing insulation between two skins of said walls, said method using an apparatus according to any of the previous claims, said method comprising the steps of:

transporting, by said bead transportation means, said dry bead insulation from said bead container to said dispensing head via said bead supply pipe;
transporting, by said adhesive fluid transportation means, said 10 adhesive fluid to said dispensing head via said adhesive supply pipe;
dispensing, by said dispensing head, bounded bead insulation, comprising said dry bead insulation and said adhesive fluid, into said cavity walls;
determining, by said dry bead flow meter, a measure for said flow rate of said transported dry bead insulation measuring an under pressure in any of said dispensing head or said bead supply pipe;
determining, by said adhesive fluid flow meter, a measure for said flow rate of said transported adhesive fluid;
determining and providing, by said control unit, said ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures, wherein said control unit comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, said method comprising the further step of:
controlling, by said control unit, at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.

In an example, the control unit comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, said method comprising the further step of:

controlling, by said control unit, at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.

In another example, the step of controlling comprises at least one of proportionally, integrally and derivatively controlling said at least one of said adhesive fluid transportation means and said bead transportation means.
Here, the control unit further may further comprise flow rate settings for at least one of said transported adhesive fluid and said transported dry bead insulation, said method comprising the further step of:

controlling, by said control unit, at least one of said adhesive fluid transportation means and said bead transportation means based on said determined measures and said flow rate settings.

In an even further example, the bead transportation means comprise an air compressor, connected to said dispensing head via an air supply pipe, wherein said bead supply pipe and said air supply pipe are arranged such that said dry bead insulation are transported to said dispensing head via a venture process, wherein said apparatus further comprises a ball valve comprised in said air supply pipe, and wherein said method comprises the further step of:

manually controlling a flow rate of air through said air supply pipe.

The expressions, i.e. the wording, of the different aspects comprised by the apparatus according to the present invention should not be taken literally. The wording of the aspects is merely chosen to accurately express the rationale behind the actual function of the aspects.
In accordance with the present invention, different aspects applicable to the above mentioned examples of the apparatus, including the advantages thereof, correspond to the aspects which are applicable to the method, according to the present invention.
The above-mentioned and other features and advantages of the invention will be best understood from the following description referring to the attached drawings. In the drawings, like reference numerals denote identical parts or parts performing an identical or comparable function or operation.
The invention is not limited to the particular examples disclosed below in connection with a particular type of apparatus for dispensing bead insulation into cavity walls.

Figure 1 is an overview of an apparatus according to the present invention for dispensing bead insulation into cavity walls.
Figure 2 discloses a flow chart of a method for dispensing the bead insulation into cavity walls.

Figure 1 discloses an apparatus 1 for dispensing bead insulation into cavity walls 13 for providing insulation between two skins of said walls. The apparatus 1 is comprised of two separate objects, i.e. the dispensing head 15 and the main cabinet 2.
The dispensing head 15, or injection gun, is typically a hand held device to be held by one or two hands during operation thereof. The main cabinet 2 is typically a moveable, transportable object, for example equipped with wheels, such that an operator is able to transport it.
During operation, the nozzle of the dispensing head 15 is placed inside the cavity wall 13 such that the bounded bead insulation is dispensed in the space between the two skins of the cavity wall 13. Once the dispensing head 15 is in place, the actual dispensing of the bounded bead insulation may start. The dispensing may start by manually opening the ball valve 16 comprised in the air supply pipe, which will be explained in more detail later on.
The main cabinet 2 comprises the bead container 10 which is arranged for storing the dry bead insulation, i.e. the insulation without having added any adhesive fluid. The dry bead insulation may be in the form of beads in the range of 2 and 6 centimetre and may be comprised of expanded polystyrene. The bead container 10 is connected to the dispensing head 15 via a bead supply pipe.
In the present example, the bead transportation means are comprised of an air compressor 9 connected to the dispensing head 15 via an air supple pipe, and arranged for providing an air flow to said dispensing head 15. The air flow running through the dispensing head 15 causes a suction effect, i.e. a venture effect, such that the dry bead insulation is sucked through the bead supply pipe to the dispensing head 15.
The main cabinet 2 further comprises an adhesive container connected to the dispensing head 15 via an adhesive supply pipe, and is arranged for storing the adhesive fluid. The adhesive fluid may be in the form of a liquid or a gas. Adhesive fluid transportation means, for example in the form of a motor 11 in combination with a peristaltic pump 6, are arranged for transporting the adhesive fluid from the adhesive container 5 to the dispensing head 15.
The aforementioned pipes may comprise flexible pipes, having a length of between 20 meters to 80 meters, preferably between 45 - 65 meters such that an operator is provided with flexibility for placing the dispensing head in the cavity wall 13.
In accordance with the present invention, the dry bead flow meter 17 is arranged for determining a measure for a flow rate of said transported dry bead insulation and the adhesive fluid flow meter 12 is arranged for determining a measure for a flow rate of said transported adhesive fluid.
The main cabinet 2 further comprises a control unit 3 in electronic communication with said dry bead flow meter 17 and said adhesive fluid flow meter 12, and is arranged for determining and providing a ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures.
According to the present invention, the control unit 3 comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid. Such a parameter may be inputted by the operator via a user interface comprised by the apparatus, or may be inputted via a network connection or the like.
The control unit 3 is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.
The control unit 3 has several options to control the ratio of dry bead insulation to adhesive fluid, dispensed in the bounded bead insulation. First, the control unit may control the valve 8 comprised in the air supply pipe, for controlling the air flow rate provided by the air compressor 9. The air pressure in the air supply pipe may then be measured by a pressure sensor 7 to validate, by the control unit 3, the air flow rate. The control unit 3 may, alternatively, also control the peristaltic pump 6 for setting a flow rate of the adhesive fluid flowing to the dispensing head 15.
The control unit 3 may also continuously monitor the pressure value measured by the pressure sensor 7, such that, whenever a pressure is detected which is too low, the valve 8 is being closed. As such, pressure sensor 7 is a sort of safety measure for the system.
As such, the control unit 3 is arranged to compensate the actual dispensed ratio of dry bead insulation to adhesive fluid, dispensed in the bounded bead insulation, towards the predetermined desired ratio.
An adhesive valve 14 may be comprised in the adhesive fluid supply pipe, for controlling the flow rate of the adhesive fluid. The adhesive valve 14 may be a pressure relieve valve, i.e. a valve which automatically mechanically closes when no adhesive fluid is being transported, for example when the adhesive fluid container is empty.
In the present example, the apparatus may comprise a remote control in electronic communication with the control unit, wherein an operator is able to set the desired ratio of adhesive fluid to dry bead insulation via the remote control. Further, the operator is able to control any of the means present in the apparatus, for example to start or shut down the apparatus as a whole.
Figure 2 discloses a flow chart of a method for dispensing the bead insulation into cavity walls.
As such, the flow chart discloses a method 101 for dispensing bead insulation into cavity walls for providing insulation between two skins of said walls, said method using an apparatus according to any of the previous claims, said method comprising the steps of:

transporting 102, by said bead transportation means, said dry bead insulation from said bead container to said dispensing head via said bead supply pipe;
transporting 103, by said adhesive fluid transportation means, said adhesive fluid to said dispensing head via said adhesive supply pipe;
dispensing 104, by said dispensing head, bounded bead insulation, comprising said dry bead insulation and said adhesive fluid, into said cavity walls;
determining 105, by said dry bead flow meter, a measure for said flow rate of said transported dry bead insulation;
determining 106, by said adhesive fluid flow meter, a measure for said flow rate of said transported adhesive fluid;
determining and providing 107, by said control unit, said ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures.

It will be clear to those skilled in the art, that the invention is described above by means of several embodiments. However, the invention is not limited to these embodiments. The desired protection is defined by the appended claims.

Claims

An apparatus (1) for dispensing bead insulation into cavity walls (13) for providing insulation between two skins of said walls, said apparatus comprising:
- a dispensing head (15) arranged for dispensing bounded bead insulation, comprising dry bead insulation and adhesive fluid, into said cavity walls;

- a bead container (10) connected to said dispensing head (15) via a bead supply pipe, and arranged for storing said dry bead insulation;

- bead transportation means arranged for transporting said dry bead insulation from said bead container to said dispensing head via said bead supply pipe;

- an adhesive container (5) connected to said dispensing head (15) via an adhesive supply pipe, and arranged for storing said adhesive fluid;

- adhesive fluid transportation means arranged for transporting said adhesive fluid to said dispensing head via said adhesive supply pipe,
the apparatus being characterized in that it further comprises:
- a dry bead flow meter (17) arranged for determining a measure for a flow rate of said transported dry bead insulation, wherein said dry bead flow meter (17) is arranged for determining said measure for said flow rate of said transported dry bead insulation by measuring an under pressure in any of said dispensing head or said bead supply pipe;

- an adhesive fluid flow meter (12) arranged for determining a measure for a flow rate of said transported adhesive fluid;

- a control unit (3) in electronic communication with said dry bead flow meter (17) and said adhesive fluid flow meter (12), and arranged for determining and providing a ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures, and wherein:
- said control unit (3) comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, and

- said control unit (3) is further arranged for controlling at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.
Apparatus according to claim 1, wherein said control unit (3) comprises at least one of a proportional, integral and derivative controller for controlling said at least one of said adhesive fluid transportation means and said bead transportation means.
Apparatus according to any of the previous claims, wherein at least one of said adhesive fluid transportation means and said bead transportation means comprises a valve (8, 14), and wherein said control unit (3) is arranged to control said at least one valve based on said determined ratio and said desired ratio.
Apparatus according to any of the previous claims, wherein said adhesive fluid flow meter (12) is arranged for measuring, in said adhesive fluid pipe, said flow rate of said transported adhesive fluid.
Apparatus according to any of the previous claims, wherein said bead transportation means comprise an air compressor (9), connected to said dispensing head (15) via an air supply pipe, wherein said bead supply pipe and said air supply pipe are arranged such that said dry bead insulation are transported to said dispensing head (15) via a venturi process.
Apparatus according to claim 5, wherein said apparatus further comprises a flow meter for measuring an air flow in said air supply pipe for determining whether said dry bead insulation are being transported.
Apparatus according to claim 6, wherein said flow meter comprises a reed switch for determining whether said dry bead insulation are being transported.
Apparatus according to any of the claims 5 - 7, wherein said apparatus further comprises a pressure sensor (7) in electronic communication with said control unit (3), and arranged for measuring a pressure in said air supply pipe.
Apparatus according to any of the previous claims, wherein said apparatus further comprises a check valve comprised in said adhesive supply pipe for preventing transported adhesive to said dispensing head to return into said adhesive supply pipe.
Apparatus according to any of the previous claims, wherein said adhesive fluid transportation means comprise a peristaltic pump (6) in communication with said control unit (3) and arranged for pumping said adhesive fluid.
A method for dispensing bead insulation into cavity walls (13) for providing insulation between two skins of said walls, said method using an apparatus according to any of the previous claims, said method comprising the steps of:
- transporting, by said bead transportation means, said dry bead insulation from said bead container (10) to said dispensing head (15) via said bead supply pipe;

- transporting, by said adhesive fluid transportation means, said adhesive fluid to said dispensing head via said adhesive supply pipe;

- dispensing, by said dispensing head (15), bounded bead insulation, comprising said dry bead insulation and said adhesive fluid, into said cavity walls;

- determining, by said dry bead flow meter (17), a measure for said flow rate of said transported dry bead insulation measuring an under pressure in any of said dispensing head or said bead supply pipe;

- determining, by said adhesive fluid flow meter (12), a measure for said flow rate of said transported adhesive fluid;

- determining and providing, by said control unit (3), said ratio of transported dry bead insulation to transported adhesive fluid based on said determined measures, wherein said control unit (3) comprises ratio settings for indicating a desired ratio of transported dry bead insulation to transported adhesive fluid, said method comprising the further step of:
- controlling, by said control unit (3), at least one of said adhesive fluid transportation means and said bead transportation means based on said determined ratio and said desired ratio of transported dry bead insulation to transported adhesive fluid.