Airflow resistance test system and method

Abstract

Disclosed are systems and methods for determining the airflow resistance of porous materials. In particular there is provided an airflow testing system for determining airflow resistance of mineral wool, the airflow testing system comprising a test chamber configured to receive a test sample, an upstream pressure sensor configured to detect the air pressure upstream of a test sample when the test sample is positioned in the test chamber, wherein the test chamber is configured to receive a supply of air from an air supply system, the airflow testing system further comprising a sample transfer mechanism configured to convey test samples into and out of the test chamber, wherein the sample transfer mechanism comprises a piston with a perforated piston plate.

Description

[0001] AIRFLOW RESISTANCE TEST SYSTEM AND METHOD

[0002] FIELD OF THE INVENTION

[0003] The invention relates to improved testing systems and methods for determining the airflow resistance of porous materials, in particular fibre-based products such as mineral wool. The systems and methods described herein are particularly easy, accurate and reliable to use.

[0004] BACKGROUND

[0005] Mineral wool - also commonly referred to as stone wool, mineral fibre, mineral cotton and as man-made vitreous fibres (MMVF) - is able to be manufactured using a variety of different techniques. The mineral wool can also be processed in a number of ways and is able to be formed into various types of products. This means it is important to be able to assess the properties of the mineral wool to confirm they are as expected and meet quality control standards.

[0006] Some techniques used to assess mineral wool are destructive, causing permanent damage to a product and some techniques are non-destructive. The destructive techniques include an analysis method that tests the product to destruction or requires a sample to be taken from the product for testing. In contrast, the non-destructive techniques do not damage the product.

[0007] Conventional testing techniques for mineral wool require significant input from human operators, such as a production line operator. The standard approach is for the operator to manually remove a product or sample of a product from the production line and place this on or into a machine in which a specific parameter test is to be carried out. These machines are usually located in a lab, and are separated from the production line.

[0008] Due to these factors testing the mineral wool requires a significant amount of operator time. Furthermore, a human operator must interact directly with both the production line and test machinery which poses safety concerns. There is therefore a need to reduce the amount of operator involvement required for manufacturing and testing mineral wools. This needs to be achieved while maintaining the accuracy and speed of testing, and whilst providing an adequate operating environment in which to conduct testing safely.

[0009] SUMMARY OF INVENTION

[0010] The invention described herein provides an accurate, automated and safe means for testing airflow resistance of mineral wools and other porous materials. Mineral wool is also commonly referred to as stone wool, mineral fibre, mineral cotton and as man-made vitreous fibres (MMVF) and includes examples such as stone wool and slag wool.

[0011] According to a first aspect, there is provided an airflow testing system for determining airflow resistance of mineral wool, the airflow testing system comprising: a test chamber configured to receive a test sample; an upstream pressure sensor configured to detect the air pressure upstream of a test sample when the test sample is positioned in the test chamber; and wherein the test chamber is configured to receive a supply of air from an air supply system; the airflow testing system further comprising a sample transfer mechanism configured to convey test samples into and out of the test chamber, wherein the sample transfer mechanism comprises: a piston with a perforated piston plate configured to move through the test chamber so as to push a test sample into or out of the test chamber; and wherein the perforated piston plate comprises a plurality of through holes such that air may pass through the perforated piston plate to a test sample received within the test chamber.

[0012] The effect of test samples on airflow from the air supply system may be identified by comparing pressure measurements upstream of a test sample from the upstream pressure sensor either to a measurement from a downstream pressure sensor configured to detect the air pressure downstream of a test sample, or to a reference measurement from the upstream pressure sensor when no test sample is within the test chamber. Airflow testing systems in accordance with this aspect can automatically load and unload samples into the test chamber using their sample transfer mechanisms. Therefore, operator involvement is reduced and safety is improved. Moreover, using a perforated piston plate to drive test samples into and / or out of the test chamber allows for the operation of the air testing system to be improved over conventional designs. The perforated piston plate can remain in place during testing as air is supplied to the test chamber and a test sample inside. No delay occurs with removing the piston and / or sealing the test chamber. Furthermore, the perforated piston plate allows air through whilst the test sample is being conveyed into and out of the test chamber. This helps prevent any vacuum building as a test sample is conveyed, reducing forces on the test sample and thereby avoiding damage or deformation to the test sample which might affect test results.

[0013] The airflow resistance of the test sample may be determined based on the differential pressure across the test sample and the volumetric flow rate of air delivered to the test chamber and passing through the test sample. The volumetric flow rate of air is equivalent to the average velocity of air through the test chamber multiplied by the cross-section of the test chamber. As such, a controller or user operating the system receive a measurement of their the volumetric flow rate or velocity of air through the test chamber.

[0014] In some examples, the system may comprise a downstream pressure sensor configured to detect the air pressure downstream of a test sample when the test sample is positioned in the test chamber. The upstream and downstream pressure sensors may detect the air pressure upstream and downstream of the test sample and the differential pressure may be calculated as the difference between these measurements. In these examples, the test chamber is preferably sealed between the upstream and downstream pressure sensors so that accurate measurements of the effect of a test sample is achieved.

[0015] In further examples, the system may be configured to obtain a reference air pressure measured by the upstream pressure sensor when there is no test sample within the test chamber may be compared to pressure measurements taken when a test sample is received in the test chamber. In such examples a downstream pressure sensor may not be required or comprised within the system.

[0016] The upstream pressure sensor and downstream pressure sensor (if present) may each be a manometer, miniscope or any other suitable pressure sensor.

[0017] The terms “upstream” and “downstream” used herein will be understood to define the positions of objects relative to the flow of air through the system during testing. Upstream components are understood to be positioned closer to the air supply system - the source of the air flow - than downstream components, such that during use air flows from upstream components towards downstream components. As such, the air supply system is considered upstream of the test chamber and pressure sensor(s). Equally, the upstream pressure sensor will be understood to be positioned closer to the air supply system than the downstream pressure sensor along the path of air flow from the air supply system.

[0018] Where the system comprises two pressure sensors (the upstream and downstream pressure sensors), the sample transfer mechanism is configured to convey the test sample into the test chamber such that the test sample is positioned between the two sensors, with the upstream pressure sensor is positioned closer to the air supply system than the test sample along the path of air from the air supply system and the downstream pressure sensor is positioned further from the air supply system than the test sample along the path of air. Hence, the upstream sensor is configured to measure properties of airflow before the air encounters a test sample within the test chamber, and the downstream sensor is configured to measure properties of air flow after the air has passed through the test sample. Whereas, where the system comprises a single pressure sensor (an upstream pressure sensor), the sample transfer mechanism is configured to convey the test sample into the test chamber such that the test sample is positioned further from the air supply system than the upstream pressure sensor along the path of air flow from the air supply system. In these examples the upstream pressure sensor is able to measure properties of air flow before the air reaches any test sample received within the test chamber.Airflow resistance is an important property to measure for mineral wools, being particularly indicative of the noise insultation performance of the wool since sound waves propagate through air. In turn, the noise performance of mineral wools is particularly important when using mineral wools as ceiling or roof insulation, or as acoustic panels in buildings. It is important to test the airflow resistance to ensure appropriate noise insulation is being achieved. Moreover, changes to the airflow resistance between samples can indicate issues with feedstocks, manufacturing processes and product handling systems.

[0019] Preferably the test chamber is cylindrical or cuboidal, having a constant cross section along a longitudinal direction in which the test chamber extends and along which air is configured to flow during use. In particularly preferred examples the test chamber is a cylinder with an internal diameter in the range of 100 to 300 millimetres, preferably in the range of 150 to 250 millimetres and more preferably still the internal diameter of the test cylinder is 205 millimetres. Preferably the test chamber has a height of at least double the height of test samples with which it is to be used. Preferably the test chamber has a height of at least 200 millimetres, more preferably at least 400 millimetres, more preferably still at least 600 millimetres, even more preferably at least 800 millimetres.

[0020] Test samples are preferably arranged to conform to the outer shape of the test chamber such that they fill the internal cross section of the test chamber. For example, when using mineral wool a test sample may be cut from a larger section of mineral wool using a punch or die cutter which has the same shape and dimensions as the cross section of the test chamber. As such, the test sample which is cut using these punch or dies will accurately fill the interior of the test chamber without being substantially compressed or deformed which might otherwise affect test results. Therefore, the airflow testing system may be located separately from a production line for producing porous materials such as mineral wool. A test sample may be removed or cut from the production line and taken to the airflow testing system for analysis. Alternatively, the test sample may be cut with a band saw or any other suitable device. A template may be used to ensure that the shape of the test sample conforms to the shape of the test chamber. Preferably the test sample has a cross section that is substantially the same as the internal cross section of the test chamber. For instance, the shape of a cross section of the test sample may correspond to the shape of the internal cross section of the test chamber. Each dimension of the cross section of the test sample may be in the range from 5 millimetres less than the corresponding dimension of the test chamber to 5 millimetres greater than the corresponding dimension of the test chamber, or more preferably in the range from 1 millimetre less than the corresponding dimension of the test chamber to 3 millimetres greater than the corresponding dimension of the test chamber, and more preferably still preferably in the range from equal to the corresponding dimension of the test chamber to 2 millimetres greater than the corresponding dimension of the test chamber. In particular, ensuring the test sample has dimensions that are equal to or slightly larger than the test chamber ensures a good seal between the walls of the test chamber and the exterior of the test chamber. For instance, where the test chamber is cylindrical with a diameter of 205 millimetres, the test sample is preferably also cylindrical with a diameter in the range of 204mm (1 millimetre less than the corresponding dimension of the test chamber) to 208 millimetres (3 millimetre greater than the corresponding dimension of the test chamber) and more preferably in the range of 205mm (equal to the corresponding dimension of the test chamber) to 207 millimetres (2 millimetre greater than the corresponding dimension of the test chamber). The testing system is well suited to measure the properties of test samples having heights in the range from 50 to 500 millimetres. For example the test samples may have a height of 110 millimetres or 300 millimetres. Therefore, in particularly preferred examples the airflow testing system is configured to test the properties of cylindrical test samples with a diameter in the range from 205 millimetres to 207 millimetres and a height of 110 millimetres. Particularly, thick materials may be divided along their thickness to create multiple test samples and the results from each test sample averaged to obtain an overall estimate for their airflow properties.

[0021] The perforated piston plate can be driven through the test chamber by the piston so as to push a test sample into or out of the test chamber. The piston is preferably configured to extend and drive the perforated piston plate in a direction parallel to the longitudinal axis of the test chamber and more preferably still in a direction parallel to the direction of air flow through the test chamber during use. The perforated piston plate will be understood to be a substantially planar body that extends in a plane that is substantially perpendicular to the direction in which the piston is configured to extend preferably a substantially planar perpendicular to the direction of in which the piston is configured to extend.

[0022] It will be understood that the through holes are apertures or perforations that extend through the perforated piston plate from an upstream face of the plate to a downstream face of the plate, such that the two sides of the plate are fluidly connected. As such, during operation air supplied to the test chamber may flow through the perforated piston plate to the test sample. Preferably the through holes extend perpendicular to the upstream and downstream faces of the plate. Preferably the through holes extend parallel to the direction of longitudinal axis of the test chamber and the direction of movement of the piston. Herein the term “face” is primarily understood to refer to the relatively large upstream and downstream faces of the perforated piston plate that are substantially perpendicular to the direction in which the piston extends, rather than any face that may be present at the circumference or exterior of the plate which has a relatively small height.

[0023] Preferably the perforated piston plate has an open area of at least 40%, preferably at least 50%, more preferably still at least 60%. The open area will be understood as the proportion of the combined area of the through holes in comparison to the overall area of the faces of the perforated piston plate. It will be appreciated that these areas are substantially perpendicular to the direction in which the piston is configured to extend and move the perforated piston plate and preferably substantially perpendicular to the longitudinal axis of the test chamber and the direction along which air flows through the test chamber during use. A high open area helps ensure that air may easily flow through the perforated piston plate. Moreover, a high open area helps ensure that the airflow resistance of the perforated piston plate is very small or negligible in comparison to typical test samples. Therefore, the presence of the perforated piston plate may not affect the results of airflow resistance testing significantly, allowing testing accuracy to be improved.

[0024] Preferably the through holes and the open area of the perforated piston plate are distributed evenly across each face of the perforated piston plate. As such, it will be understood that different subsections of the face of the perforated piston plate have approximately the same proportion of open area. For example, each half, third or quarter of each face of the perforated piston plate may have substantially the same proportion of open area. Again, this reduces the effect of the perforated piston plate on air passing therethrough and reduces the airflow resistance of the perforated piston plate. Testing accuracy is further improved.

[0025] Preferably the perforated piston plate has a large number of through holes - e.g. at least 50, at least 100 or at least 250 through holes. Thus air may easily flow through the perforated piston plate, but test samples may be well supported whilst conveyed by the plate. The perforated piston plate may be a solid disc through which holes are formed (e.g. by machining, casting or printing) and / or the plate may comprise a mesh, grating or wire net.

[0026] In particularly preferred examples the through holes are arranged substantially symmetrically across a face of the perforated piston plate. For instance, the through holes may be rotationally symmetric with order 2, 3, 4, 5, 6 or more. Equally, the through holes may have two or more lines of reflective symmetry. A symmetric perforated piston plate will minimise the effect of the plate on the air flowing through it, helping to ensure laminar flow and to provide consistent and accurate results. Alternatively, the through holes may be organised in a random or pseudo random arrangement, wherein preferably the through holes remain evenly spread across the faces of the perforated piston plate.

[0027] Preferably each of the plurality of through holes has a minimum dimension of at least 0.5 mm in the plane of the perforated piston plate, preferably at least 1 mm, more preferably at least 2 mm, more preferably still at least 3 mm. These relatively large apertures reduce the effect of the edges of the through holes on the air flowing therethrough. This helps minimise turbulence and ensure laminar flow, thereby improving the consistency and accuracy of test results.

[0028] Preferably, the perforated piston plate is configured to be positioned upstream of a test sample within the test chamber during a testing operation. Thus the airflow testing system may be configured such that air received the air supply system will pass through the perforated piston plate to a test sample within the test chamber.

[0029] For example, the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position, wherein, when the perforated piston plate is in its test position, the perforated piston plate is located between the air supply system and any test sample within the test chamber. Therefore, when in its test position, the perforated piston plate is located upstream of the test chamber or at an upstream end of the test chamber. As such, air from the air supply system may pass through the perforated piston plate into the test chamber and to any test sample positioned inside.

[0030] In some examples the airflow testing system is configured such that, when the perforated piston plate is in its test position, the perforated piston plate is located downstream of the upstream pressure sensor. As such, during testing operations the perforated piston may be located between the upstream pressure sensor and a test sample. This arrangement may be important where (for example) the test chamber is arranged vertically as the perforated piston plate may be required to support the test sample in the test chamber during test. However, in further examples, the airflow testing system may be configured such that, when the perforated piston plate is in its test position, the perforated piston plate is located upstream of the upstream pressure sensor. In such an arrangement the effect of the perforated piston plate on measurements from the upstream pressure sensor and downstream pressure sensor(if present) are minimised. In contrast, the sample receiving position may be located downstream of the test chamber or at a downstream end of the test chamber and downstream of a downstream pressure sensor such that piston is actuated to move the perforated piston plate and any test sample upstream when moving the perforated piston plate from its sample receiving position to its test position.

[0031] Preferably, the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position, wherein the sample transfer mechanism is configured to actuate the piston to move the perforated piston plate between its sample receiving position and test position, and wherein the perforated piston plate is configured to lower a test sample received thereon into the test chamber when moved from its sample receiving position and its test position. Therefore, actuating the piston may lower the perforated piston plate and any test sample thereon into the test chamber. Lowering a test sample into the chamber rather than pushing or driving it with a piston reduces the forces that must be applied to the test sample when conveying the test sample into the test chamber. This helps avoid deformation of the test sample and improves accuracy and reliability of test results. In particularly preferred examples, the test chamber may be orientated vertically, and the perforated piston plate may be configured to be move in a vertical direction along a longitudinal axis of the test chamber. Preferably, when the perforated piston plate is positioned in the sample receiving position, the perforated piston plate is directly above the test chamber and the perforated piston plate can be lowered down through the test chamber to its test position. The airflow testing system may be further configured such the perforated piston plate is configured to push a test sample out of the test chamber when moved from its test position to its sample receiving position. As such, returning the perforated piston plate to its sample receiving position may be used to discharge a test sample from the test chamber after a testing operation. Various alternative means of discharging the test sample after airflow resistance testing may also be provided.

[0032] Various alternative arrangements of the piston and the perforated piston plate are also possible. For example, instead of lowering a test sample into the test chamber for testing and pushing the test sample out of the test chamber after testing, the piston and perforated piston plate may be configured to push or drive the test sample into the test chamber. For example, the test chamber may extend in a horizontal or substantially horizontal direction and the piston may be configured to drive the perforated piston plate and any test sample from a sample receiving position laterally into the test chamber. Alternatively, the test chamber may be located above (e.g. vertically above) the sample receiving position and the piston may be configured to drive the perforated piston plate upwards to a test position, and a test sample supported thereon upwards into the test chamber. In this latter example lowering the perforated piston plate from the test position to the sample receiving position may lower the test sample so the test sample may be discharged after testing.

[0033] In various examples, the perforated piston plate may be configured to support the test sample within the test chamber during a testing operation.

[0034] In preferred examples the piston is a pneumatic piston, a hydraulic piston, or a piston actuated by a servomechanism, an electric servomechanism or a motor. Such that the piston rod and perforated piston plate are driven pneumatically, hydraulically, electrically or using a motor. Various further examples of drive means for the piston are also possible.

[0035] In particularly preferred examples the sample transfer mechanism comprises two pistons configured to transfer the test sample. As such, the piston discussed above may be a first piston, and the sample transfer mechanism may further comprise a second piston, wherein the first piston is configured to push a test sample into the test chamber and the second piston is configured to push the test sample out of the test chamber, or, the second piston is configured to push a test sample into the test chamber and the first piston is configured to push the test sample out of the test chamber. Therefore, the sample transfer mechanism comprises two pistons, one piston that loads or inserts a test sample into the test chamber and another piston which discharges the test sample from the test chamber. Both loading and discharge of the test chamber may be performed reliably and in an automated manner. The first piston and second pistons may comprise any of the features of the pistons discussed above. As such, the first and second pistons may comprise respective first and second perforated piston plates and / or any of the other features discussed above.

[0036] In preferred examples the second piston is arranged to oppose the first piston such that a test sample may be received therebetween. In such examples the first and second pistons may be configured such that they extend in opposite directions and retract in opposite directions. These directions may be colinear or parallel to the centreline or longitudinal axis of the test chamber.

[0037] As previously discussed, in particularly preferred examples where the test chamber is orientated in a vertical direction the first piston may be configured to lower and retract from a sample receiving position to a test position, lowering a test sample thereon into the test chamber. The second piston may additionally be configured to extend downwards over the test sample, pushing the test sample downwards into the test chamber. This may ensure that the test sample is reliably positioned in the test chamber, such that frictional forces between the test sample and internal walls of the test chamber are overcome and the test sample is inserted fully into the test chamber. To discharge the test sample the second piston may be retracted upwards away from the test sample and the first piston actuated to extend, pushing the test sample upwards out of the test chamber.

[0038] In some examples the second piston may be actuated to separate it from the test chamber and the test sample before air is supplied to the test chamber and the airflow resistance properties of the contents of the test chamber are measured. However, this is not essential and, as mentioned, the second piston may comprise a second perforated piston plate which comprises any of the features of the perforated piston plates of the pistons discussed above. The second perforated piston plate of the second piston may comprise a plurality of through holes such that air may pass through the perforated piston plate. The second piston may be positioned upstream of the test sample during a testing operation and may be configured such that air that has passed through the test sample continues through the second perforated piston plate of the second piston. Preferably the airflow testing system further comprises a sample receiving table, and wherein the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position, and wherein, when the perforated piston plate is in its sample receiving position, a face of the perforated piston plate is substantially coplanar with the sample receiving table. Therefore, test samples may be received at the sample receiving table and easily transferred to the perforated piston plate. Test samples may be slid from the sample receiving table to the perforated piston plate. Preferably, when the perforated piston plate is in its sample receiving position, any gap between the sample receiving table and the perforated piston plate is small - e.g. less than 25 mm, preferably less than 15 mm, more preferably less than 10 mm, and more preferably still less than 5 mm.

[0039] By substantially coplanar it will be understood that the sample receiving table and perforated piston plate are substantially parallel and arranged at a similar height when the perforated piston plate is in its sample receiving position. The difference in height between the sample receiving table and the perforated piston plate when the perforated piston plate is in its sample receiving position may be less than 15 mm, preferably less than 10 mm, and more preferably still less than 5 mm. These dimensions allow test samples to be easily slide from the sample receiving table onto the perforated piston plate. However, in alternative examples the system may be configured to actuate the piston such that piston projects past the sample receiving table and the perforated piston plate is supported away from the sample receiving table (e.g. for receiving test samples or to provide access for maintenance).

[0040] Preferably the sample receiving table comprises an aperture extending therethrough and wherein the perforated piston plate is configured to enter or fill the aperture when the perforated piston plate is in its sample receiving position. This further simplifies the process for transferring a test sample onto the perforated piston plate. The aperture may be of the same shape as the cross section of the test chamber, such that the perforated piston plate is configured to enter or fill it. Alternatively, the perforated piston plate may be configured such that it is positioned adjacent to the sample receiving table when the plate is in its sample receiving position and the sample receiving table may not comprise any significant apertures.

[0041] Despite the comments above, it will be understood that a sample receiving table is not essential and in further examples, especially examples where the test chamber extends in a non-vertical direction, the system may not include a sample receiving table.

[0042] Preferably the airflow testing system comprises an input conveyor configured to deliver a test sample to the perforated piston plate and / or the sample receiving table; and / or an output conveyor configured to discharge a test sample from the perforated piston plate and / or the sample receiving table. Therefore, test samples may be automatically delivered to and discharged from the test chamber. Testing is therefore made quicker and safer. The input and / or output conveyor is preferably a belt conveyor. However, alternative conveyors such as chain conveyors or screw conveyors may also be used.

[0043] The input and output conveyors are not essential, and in further examples test samples may be delivered to and from the testing apparatus within the airflow testing system manually or using various alternative equipment.

[0044] Preferably the airflow testing system comprising a centering mechanism configured to adjust the position and / or orientation of a test sample relative to the perforated piston plate. The centering mechanism may adjust the alignment of a test sample relative to the perforated piston plate (and relative to the test chamber). The centering mechanism may be operated when the a test sample is first received at the perforated piston plate and when the perforated piston plate is in its sample receiving position. The centering mechanism enables test samples to be accurately and repeatedly positioned on or against the perforated piston plate. Preferably the centering mechanism is configured to arrange test samples in a predetermined position and orientation relative to the perforated piston plate and test chamber such that test samples may be transferred into the test chamber without impacting the edges of the test chamber significantly. Therefore, damage or deformation to the test samples is avoided which helps ensure that the testing process is accurate and reliable.

[0045] Preferably the centering mechanism comprises two or more moveable guide plates and wherein the centring mechanism is configured to move the guide plates into an arrangement that defines therebetween a predetermined position and orientation for the test sample relative to the perforated piston plate or test chamber. As such, the guide plates may contact a test sample that is in an incorrect or unexpected position and / or orientation relative to the perforated and push the test sample into its predetermined position. The guide plates may be mounted on pneumatic, hydraulic or electric actuators. Other means of moving the guide plates are also possible. The predetermined orientation may be one where the centreline of the test sample is aligned with or collinear with a centreline of the perforated piston plate and / or the test chamber, such that the test sample may be easily conveyed into the test chamber.

[0046] The guide plates may be configured to move from an open arrangement in which the guide plates are relatively far from one another to a closed arrangement in which the guide plates define a predetermined position and orientation for the test sample therebetween. A test sample may be received at the perforated piston plate or sample receiving table whilst the guide plates are in their open arrangement, and then its position and orientation adjusted as the guide plates are closed together. Each guide plate may be configured to move in a respective direction that is substantially perpendicular to the test chamber and / or the direction of movement of the piston or the first and / or second pistons. For example, where the test chamber is oriented in a vertical direction and a piston is configured to move in a vertical direction, the airflow testing system may be configured to move the guide plates in a substantially horizontal direction, such that the guide plates contact and align test samples to the perforated piston plate of said piston.

[0047] In preferred examples, the centering mechanism may have four guide plates that are each arranged at a 45 degree offset relative to a transport direction of an input conveyor and / or output conveyor. Such an arrangement is able to reliably position test samples relative to the perforated piston plate and test chamber. However, various other arrangements of guide plates and numbers of guide plates are also possible.

[0048] In further examples a test sample may be aligned and positioned relative to the test chamber and perforated piston plate manually or the airflow testing system may comprise a fixed guide that the test sample may be placed against in a predetermined orientation.

[0049] Preferably the airflow testing system further comprises the air supply system. As such, the system may be configured to supply air to the test chamber. Alternatively, the air supply system may be independent from the airflow testing system and may be provided, sold or installed separately. The air supply system may be configured to provide air flow to the test chamber at a velocity of 696 m / s or at 14. m / s. The velocity is preferably substantially stable through testing. However, in alternative examples the airflow testing system may be configured to provide airflow at an alternative velocity or at a substantially constant volumetric flow rate. A fixed air flow velocity or flow rate provides consistency between test pieces. In preferred examples the airflow testing system 16 may be configured to provide air flow with a velocity in the range from 10 m / s to 1000 m / s or preferably from 500 to 1000 m / s.

[0050] The airflow testing system may comprise a main valve configured to allow or prevent the flow of air to the test chamber. The airflow testing system may also comprise a reduction valve configured to increase or decrease the level of flow to the test chamber. The airflow test system may further comprise a filter or separator configured to remove water or water vapour from the air delivered to the test chamber. For instance, the filter may be a silica gel filter. The airflow testing system may further comprise a flow meter configured to measure the volumetric flow rate or velocity of air flowing towards or into the test chamber.

[0051] Preferably the air testing system and air supply system are configured to provide unidirectional and / or laminar air flow to the test chamber. As such, the air flow through the perforated piston plate to a test sample also may be unidirectional and / or laminar. Airflow resistance test results achieved when such air flow is provided to the test sample are particularly accurate and consistent. The air flow rate and arrangement of through holes across the perforated piston plate may be selected so as to ensure air flow to the upstream end of the test sample is unidirectional and / or laminar during testing. Increasing the open area of the perforated piston plate, using regular or symmetric arrangements of through holes within the perforated piston plate and using relatively low air flow rates will prompt consistent, laminar flow through the test chamber. More generally, consistent and unidirectional air flow - whether it is in a laminar or turbulent regime - helps offer consistent and reliable testing results.

[0052] The air supply system may be arranged colinearly or symmetrically around the centreline of the test chamber. This again may help ensure that the airflow is consistent and / or laminar. For example, the air supply system may comprise a compressed air source (e.g. compressed air cylinders or a compressor) configured to connect to the test chamber by one or more inlets. The one or more inlets may be arranged symmetrically around the centreline of the test chamber. Alternatively, the air supply system may comprise a single fan arranged colinearly with the centreline of the test chamber and / or a plurality of fans arranged symmetrically around the centreline of the test chamber.

[0053] Preferably the airflow testing system further comprises a controller, wherein the controller is configured to receive pressure measurements from the upstream pressure sensor and downstream pressure sensor (if present). The controller may be further configured to calculate an airflow resistance, a specific airflow resistance, an airflow resistivity, an air permeability and / or an air resistance density of the contents of the test chamber based on the pressure measurements. Therefore, the airflow testing system is capable of calculating the airflow resistance and associated properties of a test sample within the test chamber. Alternatively, pressure measurements from the upstream pressure sensor and / or downstream pressure sensor may be output to a separate system for subsequent processing. For example, the airflow resistance of the contents of the test chamber (e.g. a test sample) may be calculated using:

[0054] Ap R = — v wherein R is the airflow resistance and qvis the volumetric airflow rate passing through the test chamber and test specimen. The volumetric airflow rate qvmay be received by the controller from the air supply system or from a sensor configured to measure the flow rate from the air supply system (e.g. a sensor upstream ordownstream ofthe test chamber). Alternatively, the volumetric airflow rate qvmay be calculated based on the velocity v of airflow through the test chamber and the cross-sectional area A of the test chamber.

[0055] Where the system comprises upstream and downstream pressure sensors, Ap may be calculated as the pressure differential measured across the test chamber by upstream and downstream pressure sensors. That is, Ap is the difference in pressure between the pressure measurement from the upstream pressure sensor Pi and the pressure measurement from the downstream pressure sensor p2:

[0056] Ap = Pi - p2such that:

[0057] R = =P1~P2Alternatively, Ap may be calculated as the difference between the air pressure measurement from the upstream pressure sensor when a test sample is present in the test chamber pTand a reference air pressure measurement from the upstream pressure sensor when no test sample is within test chamber p0. As such, Ap is quantifies the effect of the test sample by comparing measurements when air is supplied to the test chamber when it contains a test sample to measurements calculated when air is supplied to an empty test chamber. Thus:

[0058] Ap =Pt- p0and:

[0059] The reference pressure measurement pQmaybe measured immediately before each test sample is inserted into the test chamber, or may be stored by the system. A stored value for the reference pressure measurement pQmay be updated periodically or set by a manufacturer of the system.

[0060] A specific airflow resistance of the contents of the test chamber (e.g. a test sample) may be calculated using:

[0061] Rs= R x A wherein Rsis the specific airflow resistance, R is the airflow resistance which may be calculated through the equation above and A is the cross sectional area of the test sample perpendicular to the direction of air flow (e.g. in a plane perpendicular to the longitudinal axis of the test chamber). This specific airflow resistance Rsprovides an area-specific measurement of the airflow resistance of the test sample.

[0062] The airflow resistivity of the contents of the test chamber (e.g. a test sample) may be calculated using: wherein o is the airflow resistivity, Rsis the specific airflow resistance which may be calculated through the equation above, and d is the thickness of the test sample in the direction of air flow (e.g. parallel to the longitudinal axis of a test chamber). This calculation assumes that the material is homogenous. The airflow resistivity is sometimes referred to as the static airflow resistivity. The airflow resistivity will be seen to be independent of the cross-sectional area or depth of the test sample.

[0063] It will be seen that the airflow resistivity o could also be calculated through any of the following calculations: R X A Ap .A Ap

[0064] (J=— a 3 —=- qv. a 7=3 d —. v where the parameters take their meanings provided above.

[0065] The air permeability of the contents of the test chamber (e.g. a test sample) may be calculated using: wherein kQis the air permeability, is the dynamic viscosity of air (approximately 1 .82 x 10'5for air at 20 °C and 1 atmosphere of static pressure) and o is the airflow resistivity (also referred to as static airflow resistivity). This calculation assumes that the material is homogenous.

[0066] Assuming the viscosity of air is constant, an alternative measure of air permeability may be provided through: where I is the air permeability and o is the airflow resistivity (also referred to as static airflow resistivity).

[0067] The air resistance density of the test sample may be calculated using:

[0068] 2

[0069] SLR = p. a 3 where SLR is the air resistance density (also referred to as the Standard Air Resistance Density), p is the density of the test sample, and o is the airflow resistivity. The density p of the test sample may be calculated by measuring the mass m of the test sample and dividing the mass by the volume of the test sample. Assuming the test sample has a constant cross section, the volume of the test sample may be calculated as the product of the cross sectional area A and the thickness of the test sample d In these calculations the controller may be configured to adjust for the effect of the perforated piston plate and / or first piston (and / or the second piston if present). The controller may adjust the airflow resistance calculated in the equations based on an empirical measurement or theoretical calculation for the airflow resistance of a perforated piston plate and / or the first position (and / or the second piston). An empirical measurement for the airflow resistance of these components may be obtained by operating the airflow testing system when it is empty with no test sample or other contents within the test chamber and when all moveable components are in their respective test positions. In other examples correction may not be necessary if the airflow resistance of the perforated pressure plate and piston(s) are negligible relative to the airflow resistance of test samples. Equally, adjustment may not be necessary if the controllers’ calculations are intended to be used to identify relative properties of different test samples rather than absolute values - e.g. when comparing different test samples to each other.

[0070] As such, correction factors may be applied to the raw or measured values discussed above - e.g. the velocity or volumetric airflow through the test chamber, the pressures upstream and downstream of the test sample, and the dimensions and mass of the test sample.

[0071] The controller is not limited to these calculations and may performed further operations.

[0072] The controller may be configured to output the calculated values. For instance, the values may be stored, displayed to a user or transferred to a mineral wool production control system that is configured to monitor an overall mineral wool production process.

[0073] The controller may be configured to determine whether any of the values discussed above are within a predetermined range and / or whether any of the values are sufficiently different from historic or previous values. In this manner the controller may determine whether material properties of different test samples are diverging from expected or previously identified properties which may indicate issues with the production of the test samples. The controller may be configured to issue an alert to a user and / or an mineral wool production control system indicating that the calculated values are unexpected, being outside a predetermined range or a historic range of expected values. For example, the alert may be an audible and / or visual alarm provided to a user (e.g. using a loudspeaker, light, monitor or printer) or issue a communication to a processor or controller within a production control system that is configured to control the process of manufacturing the test sample. The manufacturing process for producing porous materials such as mineral wool may be adjusted based on the airflow resistance, resistivity and permeability values calculated for the test sample.

[0074] The controller may be configured to receive as inputs the density, height and / or weight of the test sample, and / or a material identifier that identifies the material of the test sample (e.g. a serial code or number identifying the material). The controller may be configured to calculate expected values for the properties discussed above based on these inputs and / or obtain expected values for the properties from a look-up table or other storage based on these inputs. Subsequently, the controller may be configured to compare the expected values to the calculated values derived from the calculations discussed above. If the calculated values are different from the expected values - e.g if the calculated values differ from the expected values by over 10%, preferably by over 5%, more preferably by over 2% or more preferably still by over 1 % - the controller may be configured to issue an alert as discussed above.

[0075] The controller may be local to the remaining components, being located close to or at the test chamber. Alternatively, the controller may be remote, being connected to the pressure sensor(s) by a communication line or network (e.g. the internet).

[0076] The controller may additionally be configured to control the air supply system. As such, the controller may be configured to adjust the air flow from the air supply to the test chamber. The controller may additionally be configured to control the first piston, second piston and centring mechanism (if present). The controller may be configured to control the actuation of these components, and to instruct these components to move between the respective positions as discussed above.

[0077] Therefore, the systems discussed above provide an accurate, automated and safe means for testing airflow resistance of mineral wools and other porous materials.

[0078] According to a further aspect of the invention there is provided a method for determining the airflow resistance of a test sample performed using any of the systems described above with reference to the preceding aspects of the invention. The method may comprise the steps of: receiving a test sample on or against the perforated piston plate of the piston; conveying the test sample into the test chamber using the sample transfer mechanism; receiving air flow from the air supply system to the test chamber; measuring the air pressure upstream of the test sample using the upstream pressure sensor; wherein preferably the method comprises calculating an airflow resistance, a specific airflow resistance, an airflow resistivity, an air permeability and / or an air resistance density of the test sample based on the pressure measurements based on either a difference between the air pressure upstream of the test sample measured using the upstream pressure sensor and a reference air pressure measured using the upstream pressure sensor when there is no test sample within the test chamber, or a difference between the air pressure upstream of the test sample measured using the upstream pressure sensor and the air pressure downstream of the test sample measured using a downstream pressure sensor.

[0079] Therefore, where the system includes a downstream pressure sensor, the method may comprise measuring the air pressure downstream of the test sample using the downstream pressure sensor. Equally, the method may comprise a step of measuring the air pressure using the upstream pressure sensor when no test sample is received within the test chamber - i.e. before the test sample is inserted into the test chamber or after the test sample has been removed.

[0080] Pressure measurements are obtained whilst air flow is supplied to the test chamber by the air supply system. The method may comprise any of the optional features of the systems of the previous aspect of the invention and may include any of the actions or steps described above with reference to the previous aspect of the invention. The method offers corresponding benefits to the systems described herein.

[0081] Preferably the method is a method of determining the airflow resistance of a mineral wool test sample. In this way the method provides a safe and reliable means of determining the airflow resistance of mineral wool.

[0082] The method may further comprise obtaining the test sample. For example, the test sample may be cut out of a larger portion of a material to be tested (e.g. a larger section of mineral wool). In particularly preferred examples the test sample is cut using a punch or die that has the same outer dimensions as the test chamber. As such, the dimensions of the test sample may closely conform to the test chamber.

[0083] Preferably, conveying the test sample into the test chamber comprises actuating the piston to move the perforated piston plate and lower or push the test sample into the test chamber. Conveying the test sample into the test chamber may also comprise actuating the second piston as discussed above. Before conveying the test sample into the test chamber the test sample may be aligned to the perforated piston plate and test chamber either manually, using a fixed guide or using a centering mechanism as discussed above.

[0084] Preferably receiving air flow to the test chamber comprises operating the air supply system to supply air to the test chamber. The method may comprise opening valves to release compressed air and / or actuating suitable fans within the air supply system.

[0085] Preferably the perforated piston plate remains stationary between conveying the test sample into the test chamber and the test process. For instance, the perforated piston plate may remain upstream of the test sample, such that air flow from the air supply system passes through the through holes in the perforated piston plate to the test sample. The airflow properties of the test sample may be calculated using the equations provided above. Preferably the airflow properties are calculated by a controller of the airflow testing system, but in other examples the calculation may be performed by a separate computer or controller. Such controllers may be configured to control the actuation of the air supply system, sample transfer mechanism and centering mechanism discussed above.

[0086] Therefore, the invention provides an accurate, automated and safe methods for testing airflow resistance of mineral wools and other porous materials.

[0087] BRIEF DESCRIPTION OF DRAWINGS

[0088] The invention will be described further in reference to the following drawings:

[0089] Figures 1a, 1 b, 1c and 1d show schematic cross-sections of an airflow testing system in accordance with an embodiment of the invention;

[0090] Figures 2a and 2b show schematic cross-sections schematically a further airflow testing system in accordance with an embodiment of the invention;

[0091] Figure 3 shows a schematic cross section of a further airflow testing system in accordance with an embodiment of the invention; and

[0092] Figure 4 shows a perspective view of an airflow testing system in accordance with an embodiment of the invention.

[0093] DETAILED DESCRIPTION

[0094] The figures illustrate airflow testing systems and methods of testing the airflow resistance of mineral wools and other porous materials in accordance with the invention.

[0095] Figures 1a, 1 b, 1c and 1d show schematic cross-sections of an airflow testing system 10. The drawings show the airflow testing system 10 in two different arrangements and at four different stages of a method of testing the airflow resistance of a test sample T. The test sample T is preferably a mineral wool. Figures 1a and 1 b show the airflow testing system 10 with a piston 15 and perforated piston plate 15a in a sample receiving position. Figures 1c and 1d show the airflow testing system with the piston 15 and perforated piston plate 15a in a test position.

[0096] The airflow testing system 10 comprises a test chamber 11 . The test chamber 11 has a consistent cross section and is a cylindrical or cuboidal volume configured to contain a test sample T and configured to receive a flow of air through the test sample T. The airflow received by the test chamber 11 is preferably unidirectional.

[0097] The airflow testing system 10 comprises an upstream pressure sensor 12 (a first pressure sensor) configured to detect the pressure upstream of the test chamber 11 and a downstream pressure sensor 13 (a second pressure sensor) configured to detect the pressure p2downstream of the test chamber 11. Thus the upstream pressure sensor 12 is configured to detect the pressure of air supplied from an air supply system 16 before the air reaches the test chamber 11 and any test sample T therein, whereas the downstream pressure sensor 13 is configured to detect the pressure of after which has passed through the test chamber 11 and any test sample T therein.

[0098] The test chamber 11 extends in a longitudinal direction that is parallel to the vertical direction and the z-axis. As will be seen, the test chamber 11 is a section within a larger tube 18 that connects the test chamber 11 to an air supply system 16. Specifically, the test chamber 11 is the section of the tube 18 which extends between the upstream and downstream pressure sensors 12, 13 as indicated by the hashed portion of the figure. However, other arrangements of a test chamber and surrounding tubing are also possible. As will be seen, the test chamber 11 is sealed between the upstream and downstream pressure sensors 13, 14.

[0099] The upstream and downstream pressure sensors 12, 13 are connected to and output their measurements to a controller 14. The controller 14 is configured to calculate properties of the contents of the test chamber 11 based on these measurements. For instance, the controller 14 may be configured to calculate an airflow resistance, a specific airflow resistance, an airflow resistivity, an air permeability and / or an air resistance density of the contents of the test chamber 11 using the equations and techniques discussed in the summary above. The controller may be located local to the remaining components of the system or remotely.

[0100] The airflow testing system 10 further comprises a piston 15 configured to load a test sample T into the test chamber 11 for testing and to discharge the test sample T from the test chamber after testing. As such, the piston 15 forms a sample transfer mechanism configured to convey test samples into and out of the test chamber 11. The piston 15 comprises a perforated piston plate 15a on which test samples T may be received and a piston rod 15b that is configured to be extended or retracted to raised and / or lower the performed piston plate 15a. Operating the piston 15 may move the perforated piston plate 15a through the test chamber 11 . The piston 15 is typically a pneumatic piston, however, in further examples the piston 15 may be hydraulic, electronic or driven by a motor.

[0101] The perforated piston plate 15a comprises a plurality of through holes 15c which extend through the perforated piston plate 15a from an upstream face to a downstream face of the perforated piston plate 15a. The through holes 15c allow air to pass through the perforated piston plate 15a.

[0102] The airflow testing system 10 further comprises an air supply system 16. The air supply system 16 is fluidly connected to the test chamber 11 and is configured to supply air to the test chamber 11 . The air supply system 16 may comprise fans, an air compressor, and / or stored compressed air such as a bottle of compressed air. The airflow testing system 10 is configured such that air is received from the air supply system 16 and travels from an upstream end of the test chamber 11 to a downstream end of the test chamber 11 . This flow is vertically upwards in the example shown in Figures 1a to 1d.

[0103] The airflow testing system 16 may comprise a main valve configured to allow or prevent the flow of air to the test chamber 11 . The airflow testing system 16 may also comprise a reduction valve configured to increase or decrease the level of flow to the test chamber 11. The airflow test system 16 may further comprise a filter or separator configured to remove water or water vapour from the air delivered to the test chamber 11 . For instance, the filter may be a silica gel filter. The airflow testing system 16 may further comprise a flow meter configured to measure the volumetric flow rate or velocity of air flowing towards or into the test chamber 11.

[0104] In preferred examples, testing may occur whilst the airflow testing system 16 provides air flow at a velocity of 696 m / s. However, in alternative examples the airflow testing system may be configured to provide airflow at an alternative velocity. A fixed air flow velocity provides consistency between test pieces. In preferred examples the airflow testing system 16 may be configured to provide air flow with a velocity in the range from 500 m / s to 1000 m / s.

[0105] The airflow testing system 10 also comprises a sample receiving table 17 on which a test sample T may be first received before being transferred onto the perforated piston plate 15a. The sample receiving table 17 comprises an aperture 17a where the tube 18 in which the sample chamber 11 is formed exits through the sample receiving table 17. Thus, the aperture 17a is a through hole or opening in the sample receiving table 17 in fluid communication with the air supply system via the tube 18 and test chamber 11. As shown, the sample receiving table 17 is positioned above the test chamber 11 , such that a test sample T may be lowered down from the sample receiving table 17 into the test chamber 11. The tube 18 in which the test chamber 11 is provided extends through the centre of the sample receiving table 17.

[0106] A testing process performed using the airflow testing system 10 will now be described with reference to the different arrangements shown in Figures 1a, 1 b and 1c.

[0107] Figure 1a shows the piston 15 and its perforated piston plate 15a in a sample receiving position. In this arrangement the is substantially co-planar with the surface of the sample receiving table 17. As such, the free surface 15d of the perforated piston plate 15a that opposes the piston rod 15b is co-planar with the perforated piston plate 15a, or within 10 mm or 5 mm from the surface of the sample receiving table 17. In effect, the perforated piston plate 15a completes the sample receiving table 17. As will be seen, in the sample receiving position, the piston rod 15b of the piston 15 extends through the test chamber 11 .

[0108] In this arrangement, a test sample T may be received on the perforated piston plate 15a, being positioned in contact with the free surface of the perforated piston plate 15a, as shown in Figure 1b. The test sample T may be cut from a larger section of porous material using a punch or die. The cross sectional dimensions of the test sample T are preferably the same as or substantially the same as the cross sectional dimensions of the interior of the test chamber 21 .

[0109] Once a test sample T is positioned on the perforated piston plate 15a, the piston 15 may be actuated to lower the perforated piston plate 15a and the test sample T into the test chamber 11. As shown in Figure 1c, the perforated piston plate 15a may be moved to a test position in which a test sample T thereon is positioned within the test chamber 11 between the upstream and downstream pressure sensors 12, 13. The piston 15 is controlled by the controller 14 (or another controller). The controller 14 may instruct the piston 15 to retract a fixed distance.

[0110] As will be seen, the test sample T fits tightly within the test chamber 11 , its cross- sectional dimensions being the same or slightly smaller (e.g. less than 5% smaller, preferably less than 2% smaller, more preferably less than 1 % smaller) than the cross section of the test chamber 11. The test sample T has a height which is equal to or less than the height of the test chamber 11 along its longitudinal axis.

[0111] In the test position shown in Figure 1c, the perforated piston plate 15a is located at an upstream end of the test chamber 11. In this arrangement, air may be supplied to the test chamber 11 from the air supply system 16 as shown by the arrows A in Figure 1 d. The air flows through the test chamber 11 and the vertical tube 18 with a volumetric flow rate q. The volumetric flow rate q may be output by the air supply system 16, set by instruction from the controller 14 and / or measured by a sensor between the air supply system 14 and test chamber 11 . As such, the volumetric flow rate q may be known by or set in the controller 14 and / or the controller may receive the volumetric flow rate q from the air supply system 14 or a sensor configured to measure this flow rate. The air flow delivered to the test chamber 11 and test sample T is substantially unidirectional as shown by arrows A and is preferably consistent and laminar.

[0112] Air received from the air supply system 14 will pass through the perforated piston plate 15a of the piston 15, through the test sample T and out of the remainder of the tube 18 via the opening in the sample receiving table 17.

[0113] Whilst air is supplied to the test chamber 11 and the test sample T therein, the upstream pressure sensor 12 measures an upstream pressure of the air upstream of the test sample T, before the air reaches the test sample T. Simultaneously, downstream pressure sensor 13 measures a downstream pressure p2as air exits the test sample T, downstream of the test sample T. Thus as shown, the upstream pressure sensor 12 measures air pressure in the tube vertically below the test sample T, whereas the downstream pressure sensor 13 measures air pressure in the tube vertically above the test sample T.

[0114] The pressure measurements are communicated to the controller 14. The controller calculates airflow resistance properties of the test sample T by the calculations discussed above in the summary of invention section. The airflow resistance properties are based on the pressure measurements pltp2from the pressure sensors 12, 13 as well as the air flow rate. The controller 14 may store the calculated airflow resistance properties in a database or other storage. Equally the controller 14 may transmit the calculated properties to an external processor or display the calculated properties to a user using a printer, monitor or any other suitable user interface.

[0115] The controller 14 is preferably configured to determine whether any of the calculated values for the properties discussed above are within a predetermined range and / or whether any of the values are sufficiently different from values for previous test samples. The controller 14 may issue an alert if the properties are outside the predetermined range or if the properties are sufficiently different from the values calculated for previous or historic test samples. The alert may be an audible and / or visual alarm provided to a user (e.g. using a loudspeaker, light, monitor or printer), or a communication to a further processor. Alternatively, the controller may issue a communication to a processor or controller within a production control system that is configured to control the process of manufacturing the test sample. Subsequently, the manufacturing process for producing porous materials such as mineral wool may be adjusted based on the airflow resistance, resistivity and / or permeability values calculated for the test sample T.

[0116] The perforated piston plate 15a preferably does not significantly impact the flow of air therethrough. Indeed, preferably the perforated piston plate 15a has a negligible airflow resistance in comparison to the test sample (e.g. less than 5% of the airflow resistance of typical samples of mineral wool). The perforated piston plate 15a may have a wide range of arrangements of through holes 15d. However, preferably, the perforated piston plate has an open area of at least 40% and comprises at least 50 through holes 15d, each of which has a minimum cross-sectional dimension of at least 1 mm. Therefore, the measurements of airflow resistance and associated properties of the test sample T remain very accurate. Moreover, the measurements may be obtained quickly and reliably, without needing to remove the piston from the test chamber 11 or the larger tube 18.

[0117] Following testing the piston 15 may be actuated to return perforated piston plate 15a to its sample receiving position. This pushes the test sample T out of the test chamber 11 and returns the perforated piston plate 15a and the test sample T to the sample receiving table 17. In this arrangement - which is similar to Figure 1 b - the test sample T may be removed from the airflow testing system 10 and the airflow testing system 10 is returned to the arrangement shown in Figure 1a. In this arrangement, the process may be repeated to measure the airflow properties of a different test sample. Again, the movement of the piston 15 may be controlled by the controller 14 (or another processor). For example, the controller 14 may issue an instruction to the piston 15 that instructs the piston 15 to extend by a fixed amount so that the piston 15 and perforated piston plate 15a move from their test position to their sample receiving position.

[0118] Figures 2a and 2b show schematic cross-sections of a further airflow testing system 20. This system 20 shares many features with the airflow testing system 10 shown in Figures 1a to 1d. Corresponding features have had their reference signs incremented by 10 between Figures 1 and 2. Equivalent components in the airflow testing systems 10, 20 share corresponding features and offer corresponding advantages. Therefore, further discussion of these features are provided above with reference to Figure 1 .

[0119] The airflow testing system 20 comprises a test chamber 21 configured to receive and contain a test sample (not shown for clarity). The test chamber 21 is configured to receive a flow of air therethrough by which the airflow properties of a porous test sample such as mineral wool may be determined. The airflow testing system 20 further comprises an upstream pressure sensor 22 (a first pressure sensor) and a downstream pressure sensor 23 (a second pressure sensor) configured to measure the air pressure on either side of the test chamber 21 and any test sample therein. The upstream and downstream pressure sensors 22, 23 are connected to and output their measurements to a controller 24. The controller 24 is configured to calculate properties of the contents of the test chamber 21 based on these measurements. For instance, the controller 24 may be configured to calculate an airflow resistance, a specific airflow resistance, an airflow resistivity and / or an air permeability of a test sample within of the test chamber 24 using the equations and techniques discussed in the summary above.

[0120] As in the system 10 shown in Figure 1 , the test chamber 21 shown in Figure 2a and 2b extends in a vertical direction and is a section of a tube 28 which extends vertically between an air supply system 26 and an aperture 27a or opening in the surface of a sample receiving table 27. The test chamber 21 has a consistent cross section and is preferably cylindrical or cuboidal.

[0121] The airflow testing system 20 further comprises a sample transfer mechanism that includes two pistons, a first (lower) piston 25 and a second (upper) piston 29. The first and second pistons 25, 29 are configured to insert test samples into the test chamber 21 and discharge test samples from the test chamber 21 . The first and second pistons 25, 29 are arranged to oppose each other, such that the two pistons 25, 29 extend in opposite directions and retract in opposite directions. The first and second pistons 25, 29 are arranged colinearly with the second piston 29 vertically above the first piston 25 (i.e. above the first piston 25 in the z-direction). A test sample T' positioned therebetween

[0122] Figures 2a and 2b show the airflow testing system 20 in two different arrangements. Figure 2a shows the airflow testing system 20 with its first and second pistons 25, 29 in their sample receiving positions with a test sample T' positioned therebetween. Figure 2b shows the airflow testing system with its first and second pistons 25, 29 in their test positions in which a test sample T' positioned between the first and second pistons 25, 29 is received within the test chamber 21 and may have its airflow properties tested.

[0123] The first piston 25 of the two pistons corresponds to the piston 15 shown in Figures 1a to 1d. The first piston 25 comprises a moveable first perforated piston plate 25a connected to a piston rod 25b which may be extended and retracted. The first perforated piston plate 25a comprises a plurality of through holes 25a that extend therethrough. The first perforated piston plate 25a may be identical to the perforated piston plate 15a of the piston 15 discussed above with reference to Figures 1a to 1d.

[0124] The first perforated piston plate 25a comprises a free surface 25d on its opposite side to the piston rod 15b. The free surface 25d faces upwards and is configured to support a test sample thereon. In its sample receiving position the free surface 25d of the perforated piston plate 25a is substantially coplanar with a surface of the sample receiving table 27 such that a test sample may be easily transferred from the sample receiving table 27 to the perforated piston plate 25a. From its sample receiving position shown in Figure 2a, the first piston 25 may be retracted to lower the perforated piston plate 25a into its test position in which the perforated piston plate 25a is located at an upstream end of the test chamber 21 . In this arrangement which is shown in Figure 2b the test sample T' supported thereon is positioned within the test chamber 21. Therefore, lowering the first piston 25 and perforated piston plate 25a from its sample receiving position into its test position helps insert or load test samples into the test chamber 21 . Equally, raising the first piston 25 and perforated piston plate 25a from its test position into its sample receiving position pushes test samples from the test chamber 21 , discharging the test samples from the test chamber 21 .

[0125] The second piston 29 also comprises a second perforated piston plate 29a connected to a piston rod 29b. The second perforated piston plate 29a comprises a plurality of through holes 29c through which air may travel between the opposed faces of the second perforated piston plate 29a. A free surface 25d of the second perforated piston plate 29a faces downwards towards the test chamber 21 and first piston 25.

[0126] The second piston 29 is configured to move the second perforated piston plate 29a from its sample receiving position above the sample receiving table 27 (as shown in Figure 2a) and a test position within the tube 28 at which the second perforated piston plate 29a is within the tube 28 at a downstream end of the test chamber 21 (as shown in Figure 2b).

[0127] Extending the second piston 29 may cause the free surface 29d of its second perforated piston plate 29a to contact a test sample T' and push the test sample T' into the test chamber 21 . This is of particular use when the test sample T' has similar dimensions to the test chamber 21 and frictional forces may otherwise prevent the test sample T' from easily passing into the test chamber 21.

[0128] The second perforated piston plate 29a of the second piston 29 may be identical to the first perforated piston plate 25a of the first piston 25 and / or the perforated piston plate 15a of the piston 15 discussed above with reference to Figures 1a to 1d. However, the second perforated piston plate 29a is oriented in an opposite direction in the vertical direction relative to these components that its free surface 29d faces downwards. As will be seen from Figures 2a and 2b, the air supply system 26 is arranged directly below the test chamber 21 , such that the air supply system 26 is colinear with the longitudinal axis of the test chamber 21. An outlet of the air supply system 26 is arranged symmetrically around the centreline of the test chamber21 . As such, the air received to the test chamber 21 from the air supply system 24 is particularly consistent, laminarand unidirectional. This may increase the accuracy of measurements using the system.

[0129] In use a test sample T' is received between the first and second pistons 25, 29 when the pistons 25, 29 are in their sample receiving positions. The first and second pistons 25, 29 are then actuated to move the pistons into their test positions and lower the test sample T' into the test chamber 21 . Thereafter, the air supply system 26 is operated to provide air to the test chamber 21. The upstream and downstream pressure sensors 22, 23 are configured to measure the pressure upstream and the pressure downstream p2of the test sample T. The airflow properties of the test sample T' may be determined based on the measured pressures in the manner discussed above with reference to Figures 1a to 1d. Subsequently, the first and second pistons 25, 29 may be actuated to return to their sample receiving position, moving the test sample T' from the test chamber 21 . The test sample T' may be removed from the airflow testing system and the process repeated.

[0130] Preferably the distance between the first and second perforated piston plates 25a, 29a in their test positions is greater than the height of a test sample. This prevents deformation of the test sample which may affect measurements. To further prevent deformation of the test sample, the distance between the sample receiving position and test position of the second perforated piston plate 29a may be smaller than the distance between the sample receiving position and test position of the first perforated piston plate 25a. Alternatively or additionally, the airflow testing system 20 may be configured to actuate the second piston 29 to lower the second perforated piston plate 29a into the tube 18 when inserting a test sample, before lifting the second perforated piston plate 29a by a small amount to remove any forces applied between the second perforated piston plate 29a and the test sample. This small amount may be less than the distance between the test chamber 21 and the sample receiving position of the second perforated piston plate 29a.

[0131] The first and second perforated pi”ton plates 25a, 29a allow air to flow pass therethrough via their respective through holes 25c, 29c. Therefore, the airflow testing system may be configured such that first and second perforated piston plates 25a, 29a may be configured to remain in place in their test positions during a testing operation when air is supplied to the test chamber 21 . Air may pass from the air supply system 24 to a test sample via the through holes 25c in the first perorated piston plate 25a. Air existing the test sample T' may pass from the test sample out of the airflow testing system via the through holes 29c in the second perforated piston plate. This allows for a quick and automated testing of test samples. Moreover, the ability of air to pass through the perforated piston plates 25a, 29a prevents the air being trapped and the creation of unintended regions of high and low pressure when the perforated piston plates 25a, 29a are moved through the test chamber 21 and / or tube 28.

[0132] In further examples, the second piston 29 may not comprise a perforated piston plate 29a. Instead, the second piston 29 may comprise a solid piston plate that does not allow air to pass therethrough. In such examples the second piston 29 and its solid piston plate may be lowered and moved towards the test chamber 21 to insert test samples into the test chamber 21 , and subsequently lifted and removed from the test chamber 21 and tube 28 before testing is performed.

[0133] A further airflow testing system 3” is shown In Figure 3. The airflow testing system 30 comprises a similar mechanism for handling test samples as the example in Figure 2. The system comprises a test chamber 31 into which a test sample T' may be inserted using a first piston 35 and a second 29 piston. The test chamber 31 is a cylindrical tube arranged in a vertical orientation (although other arrangements are possible). The first piston 35 comprises a perforated piston plate 35a mounted on a piston rod 35b. The first piston 35 is configured to retract so as to lower a test sample T' into the test chamber 31 and extend to push the test sample from the test chamber 31. The second piston 39 opposes the first piston 35 such that test samples T' may be received therebetween. The second piston 39 comprises a perforated piston plate 39a mounted on a piston rod 39b. The second piston 39 is configured to extend so as to push test samples T' into the test chamber 31. The second piston 39 may be removed from the test chamber 31 during testing.

[0134] The second piston 39 further comprises a thickness gauge 39c configured to measure the thickness of test sample T' received between the first and second pistons 35, 39. The second piston 39 may be lowered into contact with a test sample T' supported on the first piston 35 and the scale of the thickness gauge 39c read. The thickness of a test sample T' may be used in calculations of some airflow properties.

[0135] The first and second pistons 35, 39 may be modified to incorporate any of the features of the pistons discussed above with reference Figures 1 and 2 and vice versa.

[0136] As previously discussed, the airflow testing systems 10, 20 of Figures 1 and 2 comprise two sensors (the upstream downstream pressure sensors) positioned on either side of the test chamber and a test sample. These sensors which may measure pressure of the airflow upstream and downstream of a test sample so that the pressure drop in air flow through a test sample can be identified. In contrast, the airflow testing system 30 of Figure 3 comprises a single upstream pressure sensor 32 that is located upstream of a test sample T' when the test sample T' is received within the test chamber 31 , such that the upstream pressure sensor 32 is positioned between a test sample T' and the air supply system 36 during testing. The single upstream pressure sensor 32 may be used to identify the pressure drop in air flow through the test sample T' by comparing a reference pressure measurement taken using the upstream pressure sensor 32 when air is supplied to the test chamber but no test sample is present and a pressure measurement taken using the upstream pressure sensor 32 when air is supplied to the test chamber with a test sample inserted. The upstream pressure sensor 32 is preferably a manometer but any suitable pressure sensor may be used. The pressure measurements from the upstream pressure sensor 32 are transmitted to a reader 33 from which they may be read by a user, or to a controller configured to calculate airflow properties of the contents of the test chamber 31 . For instance, the controller may be configured to calculate a difference between a reference pressure measurement and pressure measurements for one or more test samples, and to calculate airflow properties of the contents of the test chamber 31 based on this pressure difference (e.g. using the calculations discussed in the summary of invention section above).

[0137] Air flow A' is provided to the test chamber by an air supply system 36. The air supply system 36 comprises an air passage 36a connected to an air inlet 31a of the test chamber 31. Along the air passage 36a are provided a main valve 36b configured to prevent or allow flow to the system 30 and test chamber 31 , a water separator 36c such as a silica gel filter configured to remove water or water vapour from the air supplied to the test chamber 31 , a pressure reducing valve 36d configured to provide fine adjustment of the flow of air to the test chamber 31 and a flow meter 36e configured to measure the flow of air (e.g. measure the velocity of air or the volumetric flow of air) to the test chamber 31 . These features may be present in the air supply systems discussed above with reference to Figures 1 and 2.

[0138] During operation of the airflow system 30 of Figure 3, a user may obtain a test sample, for instance by cutting the test sample T' from a larger section of material. The sample may comprise a mineral wool or other man made vitreous fibre. The user may weigh the test specimen.

[0139] The user may perform a calibration step in which the test chamber 31 is empty of a test sample, but the first piston 35 is in its lowered, test position within the test chamber 31. Air supply may be provided to the test chamber 31 and a reference air pressure measured using the upstream pressure sensor 32. The user may also optionally zero or tare the thickness gauge 39c on the second piston 39.

[0140] The test sample T' may subsequently be inserted into the test chamber 31 and measured. The first piston 35 may be raised to a sample receiving position above the test chamber 31 , the test sample T' may be placed on the perforated piston plate 35a of the first piston 35. The second piston 39 may be lowered into contact with the test sample T', and optionally the thickness of the test sample T' read using the thickness gauge. The first and second pistons 35, 39 may be lowered to insert the test sample T' into the test chamber. Optionally, the second piston 39 may be raised from the test chamber 31 before air is supplied, but this is not essential. Air is then supplied to the test chamber 31 from the air supply system 36 and a measurement of the air pressure upstream of the test sample T' taken using the upstream pressure sensor 32. Following this test, the first piston 35 and optionally the second piston 39 are raised to discharge the test sample T' from the test chamber 31.

[0141] The reader 33 may be configured to display a pressure drop between the reference air pressure and the air pressure obtained when a test sample T' is present in the test chamber 31. Alternatively, the reader 33 may be configured to display the strict pressure measured in both the calibration step and the actual test. In further examples the pressures or the pressure difference may be transmitted to a controller for further analysis and / or the calculation of airflow properties. Equally, the calibration step in which a reference air pressure is obtained may be performed after the test step.

[0142] The same air flow should be provided to the test chamber 31 from the air supply system 36 in both the calibration step and test step. As such, the position of the pressure reducing valve 36d may be kept constant between the two steps. In preferred examples the air flow may be set at 14.4 m / s or 696 m / s during testing although other figures may also be used - e.g. in a range from 10 m / s to 1000 m / s, or preferably from 500 to 1000 m / s.

[0143] As discussed above, airflow testing systems that include both an upstream pressure sensor and a downstream pressure sensor such as the examples in Figures 1 and 2 may measure the pressure upstream and downstream of a test sample simultaneously to determine the effect of the test sample on airflow therethrough. However, this is not essential. These systems may also be used in a similar manner to the example shown in Figure 3 that comprises a single upstream pressure sensor. For instance, the airflow testing systems 10, 20 shown in Figures 1 and 2 may also be operated to use their upstream pressure sensor to determine a reference pressure when no test sample is present in their test chambers and a test pressure when a test sample is received in the test chamber. These systems 10, 20 are therefore flexible in their operation.

[0144] In the examples of airflow testing systems 10, 20, 30 discussed above with reference to Figures 1 , 2 and 3, test samples may be delivered to and discharged from the system manually or using an automated sample handling system. An example of a system 100 comprising a suitable automated handling mechanism is shown in Figure 4.

[0145] Figure 4 shows an airflow testing system 100 configured to test the airflow resistance and associated properties of porous test samples such as mineral wool. The system 100 comprises a vertical test chamber 110 formed within a cylindrical tube 120. The system 100 is configured to be used with cylindrical test samples as shown by the cylindrical test sample T" shown in wire form for clarity.

[0146] The system 100 comprises a sample receiving table 130 at an upper end of the tube 120 and above the test chamber 110. The tube 120 extends through an aperture (hole) 131 within the sample receiving table 130.

[0147] The system 100 further comprises two opposed pistons configured 140, 150 to insert samples into the test chamber 110 from the sample receiving table 130 and to discharge samples from the test chamber 110 to the sample receiving table 130. The opposed pistons include a first piston 140 with a first perforated piston plate 141 mounted on a first piston rod 142 and a second piston 150 with a second perforated piston plate 141 mounted on a second piston rod 142. The first piston 140 of Figure 4 is equivalent to the first piston of Figures 2 and 3 and operates in a similar manner. The first and second perforated piston plates 141 , 151 each comprise a respective plurality of through holes 143, 153. Air may pass through the perforated piston plates 141 , 151 via the respective through holes 143, 153. The first piston 140 of Figure 4 is equivalent to the first piston of Figures 2a and 2b and operates in a similar manner. The first piston 140 is configured to move from sample receiving position in which its free surface is substantially colinear with a surface of the sample receiving table 170 to a test position in which a test sample thereon is positioned in the test chamber 110. The first piston 140 is further configured to move from its test position back to its sample receiving position to discharge a test sample from the test chamber 110. The second piston 150 of Figure 4 is equivalent to the second piston 29 shown in Figures 2a and 2b or the second piston 39 shown in Figure 3 and operates in a similar manner. The second piston 150 moves from a sample receiving position over the sample receiving table 130 to a test position within the tube 120 and may push a test sample into the test chamber 110. Further discussion of these process steps is provided above with reference to Figures 2a and 2b and Figure 3.

[0148] The airflow testing system 100 is configured to be connected to an air supply system (not shown) such that the test chamber 110 receives air from the air supply system. The airflow testing system 100 further comprises at least two pressure sensors (not shown) configured to measure the pressure within the test chamber 110. The arrangement of the test sensors may be as shown in Figures 1 and 2. Airflow resistance and other properties of a test sample within the test chamber may be calculated as discussed above.

[0149] The airflow testing system 100 further comprises an input conveyor 160 configured to convey test samples towards the sample receiving table 130 and to the first and second pistons 140, 150. The airflow testing system 100 also comprises an output conveyor 170 configured to convey test samples away from the sample receiving table 130 and the first and second pistons 140, 150. Therefore, the input conveyor 160 is configured to deliver test samples to the airflow testing system 100 for testing and the output conveyor 170 is configured to discharge test samples from the airflow testing chamber after testing. The input 160 and output conveyors 170 are configured to move test samples in a direction shown by arrow M which is parallel to the x-axis which is perpendicular to the vertical direction (the z-axis) along which the test chamber extends and in which the first and second pistons operate 140, 150. As shown, the second piston 150 is operated by a pneumatic actuator 151 , although in further examples the actuator may be hydraulic, electric or drive by a motor. The first piston 140 comprises a similar actuator (not shown) within the tube 120.

[0150] As shown, the input and output conveyors 160, 170 are belt conveyors. However, this is not essential, and any alternative suitable type of conveyor or article handling mechanism may be used in place of the belt conveyors. For instance, the input and / or output conveyors 160, 170 may be a belt conveyor, roller conveyor, cable conveyor or chain conveyor. Alternatively, the input and / or output conveyor may be replaced by a robot picking system. These automated mechanisms for transferring sample to and from the airflow testing system 100 are quick and reliable.

[0151] The airflow testing system 100 may be located separately from the main production line of a material manufacturing facility. Samples may be cut, taken or removed from the main production line and transferred to the airflow testing system 100 for testing using the input conveyor 160 and other material handling devices.

[0152] The airflow testing system 100 shown in Figure 4 further comprises a centering mechanism 180 configured to align a test sample with the test chamber 110, first piston 140 and / or second piston 150. As such, the centering mechanism is configured to adjust the position of test samples received at the airflow testing system such that they are in a predetermined orientation and position relative to the test chamber 110 and piston(s) 140, 150.

[0153] The centering mechanism 180 comprises four moveable guide plates 181. Each guide plate 181 is mounted on a respective actuator 182. The actuators 182 are pneumatic, but could in alternative examples be hydraulic or operated by a servomechanism, electric servomechanism or motor. The actuators 182 are configured to move the guide plates 181 between an open arrangement at which the guide plates 181 are relatively far apart and a closed arrangement at which the guide plates 181 are relatively close together. In the closed position the guide plates 181 define therebetween a predetermined position and orientation for a test sample. In this predetermined position and orientation the test sample is correctly located relative to the test chamber 110 and pistons 140, 150 and may be correctly inserted into the test chamber 110 without deformation or damage. For instance, the airflow testing system may be configured to move each guide plate 181 a predetermined distance between their respected positions in the open and closed arrangements.

[0154] As will be seen in Figure 4, the four guide plates 181 and actuators 182 are arranged in two opposing pairs, such that the guide plates 181 are separated by 90 degrees around the circumference of the test chamber 110 and sample receiving table 130. The guide plates 181 and actuators 182 are arranged at an angle of 45 degrees relative to the direction in which the input conveyor 160 and output conveyor 170 are configured to transfer test samples (as shown by arrow M, parallel to the x-axis). This arrangement of the guide plates 181 and actuators 182 is able to accommodate and correct the position and orientation of test samples received from the input conveyor 160 in a large range of initial positions.

[0155] In operation, a test sample is received at the sample receiving table 130 and / or on first piston 140, but may not be arranged in an appropriate location or orientation. To resolve this issue, the airflow testing system is configured to move the guide plates 181 into their closed arrangement, pushing the test sample into the predetermined position and orientation. Such a centering system offers a reliable and simple way of ensuring test samples are correctly positioned for testing, even when there is variation in the position and orientation in how the test sample first are first received by the airflow testing system 100. The guide plates 181 may then be moved back to their open arrangement to allow the test sample to be inserted into the test chamber 110 and tested, and to allow a further test sample to be received.

[0156] In further examples the guide plates 181 may be configured to push test samples from the input conveyor 160 to the sample receiving table 130 and / or from the sample receiving table 130 to the discharge conveyor 170. However, this is not essential and these steps may not be necessary depending on the arrangement of the input and output conveyors and / or may be performed manually or by a further mechanism.

[0157] The input and output conveyors 160, 170 and the centering mechanism 180 may be controlled by a controller (not shown). For example, a single controller may be configured to control the first and second pistons 140, 150, the input and output conveyors 160, 170 and the centering mechanism 180. The same controller may also be configured to receive pressure measurements and calculate airflow resistance properties of a test sample. However, this is not essential.

[0158] The input and output conveyors 160, 170 and the centering mechanism 180 of the airflow testing system 100 shown in Figure 4 may be combined with the systems 10, 20 and features discussed above with reference to Figures 1 , 2 and 3. Indeed, the features of the examples discussed above may be combined together in any appropriate arrangement.

[0159] In the examples discussed above the test chambers 11 , 21 , 31 , 110 are arranged to extend in a vertical direction. Indeed, the test chambers 11 , 21 , 31 , 110 of Figures 1 to 4 form part of a vertical tube 18, 28, 120. However, these features are not essential. In addition, the pistons 15, 25, 29, 35, 39, 140, 150 are configured to move in vertical directions lowering test samples into a test chamber for testing and raising test samples from the test chamber after testing. As such, the sample receiving positions of the pistons 15, 25, 29, 35, 39, 140, 150 and the sample receiving tables are arranged above the test chambers and test positions of the pistons 15, 25, 29, 35, 39, 140, 150. Again, these are not essential. Various further arrangements of test chambers and piston(s) are possible. The test chamber may extend in substantially any direction (e.g. horizontally) and the piston(s) may be configured to push a test sample horizontally into and / or out of the test chamber. Equally, the test chamber may be located above the sample receiving positions of one or more pistons and the piston(s) may be configured to raise test samples into the test chamber and lower the test samples from the test chamber. As such, discussion of lowering test samples into test chambers and lifting or raising test samples out of test chambers in relation to Figures 1 to 4 will be understood as specific examples of moving samples into a test chamber and moving samples out of a test chamber.

[0160] Generally, any of the control functionality described in this text or illustrated in the figures can be implemented using software, firmware (e.g., fixed logic circuitry), programmable or non-programmable hardware, or a combination of these implementations. The terms "component" or "function" as used herein generally represents software, firmware, hardware or a combination of these. For instance, in the case of a software implementation, the terms "component" or "function" may refer to program code that performs specified tasks when executed on a processing device or devices. The illustrated separation of components and functions into distinct units within the block diagrams above may reflect an actual physical grouping and allocation of such software and / or hardware, or can correspond to a conceptual allocation of different tasks performed by a single software program and / or hardware unit. Thus, the various processes described herein can be implemented on the same processor or different processors in any combination.

[0161] Calculations, methods and processes described herein can be embodied as code (e.g., software code) and / or data. Such code and data can be stored on one or more computer-readable media, which may include any device or medium that can store code and / or data for use by a computer system. When a computer system reads and executes the code and / or data stored on a computer-readable medium, the computer system performs the methods and processes embodied as data structures and code stored within the computer-readable storage medium. In certain embodiments, one or more of the steps of the methods and processes described herein can be performed by a processor (e.g., a processor of a computer system or data storage system). It should be appreciated by those skilled in the art that computer-readable media include removable and nonremovable structures / devices that can be used for storage of information, such as computer-readable instructions, data structures, program modules, and other data used by a computing system / environment. A computer-readable medium includes, but is not limited to, volatile memory such as random access memories (RAM, DRAM, SRAM); and non-volatile memory such as flash memory, various read-only-memories (ROM, PROM, EPROM, EEPROM), magnetic and ferromagnetic / ferroelectric memories (MRAM, FeRAM), and magnetic and optical storage devices (hard drives, magnetic tape, CDs, DVDs); network devices; or other media now known or later developed that is capable of storing computer- readable information / data. Computer-readable media should not be construed or interpreted to include any propagating signals.

[0162] Although specific embodiments of the disclosure have been described, various modifications, alterations, alternative constructions, and equivalents are also encompassed within the scope of the disclosure. Embodiments of the present disclosure are not restricted to operation within certain specific data processing environments, but are free to operate within a plurality of data processing environments. Additionally, although embodiments of the present disclosure have been described using a particular series of transactions and steps, it should be apparent to those skilled in the art that the scope of the present disclosure is not limited to the described series of transactions and steps. Various features and aspects of the above-described embodiments may be used individually or jointly.

[0163] The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that additions, subtractions, deletions, and other modifications and changes may be made thereunto without departing from the broader spirit and scope as set forth in the claims. Thus, although specific disclosure embodiments have been described, these are not intended to be limiting. Various modifications and equivalents are within the scope of the following claims. The modifications and variations include any relevant combination of the disclosed features.

Claims

CLAIMS1. An airflow testing system for determining airflow resistance of mineral wool, the airflow testing system comprising: a test chamber configured to receive a test sample; an upstream pressure sensor configured to detect the air pressure upstream of a test sample when the test sample is positioned in the test chamber; wherein the test chamber is configured to receive a supply of air from an air supply system; the airflow testing system further comprising a sample transfer mechanism configured to convey test samples into and out of the test chamber, wherein the sample transfer mechanism comprises: a piston with a perforated piston plate configured to move through the test chamber so as to push a test sample into or out of the test chamber; and wherein the perforated piston plate comprises a plurality of through holes such that air may pass through the perforated piston plate to a test sample received within the test chamber.

2. An airflow testing system according to claim 1 , wherein the perforated piston plate has an open area of at least 40%, preferably at least 50%, more preferably still at least 60%.

3. An airflow testing system according to any preceding claim, wherein the plurality of through holes are arranged symmetrically across a face of the perforated piston plate.

4. An airflow testing system according to any preceding claim, wherein each of the plurality of through holes has a minimum dimension of at least 0.5 mm in the plane of the perforated piston plate, preferably at least 1 mm, more preferably at least 2 mm, more preferably still at least 3 mm.

5. An airflow testing system, wherein the perforated piston plate is configured to be positioned upstream of a test sample within the test chamber during a testing operation.

6. An airflow testing system according to any preceding claim, wherein: the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position; wherein, when the perforated piston plate is in its test position, the perforated piston plate is located between the air supply system and any test sample within the test chamber.

7. An airflow testing system according to any preceding claim, wherein: the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position; wherein the sample transfer mechanism is configured to actuate the first piston to move the perforated piston plate between its sample receiving position and test position; and wherein the perforated piston plate is configured to lower a test sample received thereon into the test chamber when moved from its sample receiving position and its test position; wherein preferably the perforated piston plate is configured to push a test sample out from within test chamber when moved from its test position to its sample receiving position.

8. An airflow testing system according to any preceding claim, wherein the piston is a first piston and wherein the sample transfer mechanism further comprises a second piston, wherein: the first piston is configured to push a test sample into the test chamber and the second piston is configured to push the test sample out of the test chamber;or, the second piston is configured to push a test sample into the test chamber and the first piston is configured to push the test sample out of the test chamber.

9. An airflow testing system according to any preceding claim, further comprising a downstream pressure sensor configured to detect the air pressure downstream of a test sample when the test sample is positioned in the test chamber.

10. An airflow testing system according to any preceding claim, further comprising: a sample receiving table; wherein the perforated piston plate is configured to move between a sample receiving position outside of the test chamber at which a test sample may be received on the perforated piston plate and a test position; and wherein, when the perforated piston plate is in its sample receiving position, a face of the perforated piston plate is substantially coplanar with the sample receiving table; wherein preferably the sample receiving table comprises an aperture extending therethrough and wherein the perforated piston plate is configured to enter or fill the aperture when the perforated piston plate is in its sample receiving position.

11. An airflow testing system according to any preceding claim, further comprising: an input conveyor configured to deliver a test sample to the perforated piston plate and / or the sample receiving table; and / or an output conveyor configured to discharge a test sample from the perforated piston plate and / or the sample receiving table.

12. An airflow testing system according to any preceding claim, further comprising a centering mechanism configured to adjust the position and / or orientation of a test sample relative to the perforated piston plate; and whereinpreferably, wherein the centring mechanism comprises two or more moveable guide plates and wherein the centring mechanism is configured to move the guide plates into an arrangement that defines therebetween a predetermined position and orientation for the test sample relative to the perforated piston plate.

13. An airflow testing system according to any preceding claim, wherein the airflow testing system further comprises the air supply system.

14. An airflow testing system according to any preceding claim, further comprising a controller, wherein the controller is configured to receive pressure measurements from the upstream pressure sensor or pressure measurements from the upstream and downstream pressure sensors and to calculate an airflow resistance, a specific airflow resistance, an airflow resistivity, an air permeability and / or an air resistance density of the contents of the test chamber based on the pressure measurements.

15. A method for determining the airflow resistance of a test sample performed using the system of any preceding claim, wherein the method involves the steps of: receiving a test sample on or against the perforated piston plate of the piston; conveying the test sample into the test chamber using the sample transfer mechanism; receiving air flow from the air supply system to the test chamber; measuring the air pressure upstream of the test sample using the upstream pressure sensor; wherein preferably the method comprises calculating an airflow resistance, a specific airflow resistance, an airflow resistivity, an air permeability and / or an air resistance density of the test sample based on either: a difference between the air pressure upstream of the test sample measured using the upstream pressure sensor and a reference air pressure measured using the upstream pressure sensor when there is no test sample within the test chamber;or a difference between the air pressure upstream of the test sample measured using the upstream pressure sensor and the air pressure downstream of the test sample measured using a downstream pressure sensor.

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