Nipple for measuring speed of a stream of abrasive particles

Abstract

A nipple (10) for measuring a speed of a stream comprising abrasive particles prior to being entrained in a stream of a blasting gas is disclosed. The nipple (10) comprises a body (12) comprising a conduit (30) extending from an inlet (20) to an outlet (40). The inlet (20) is configured for connection to a supply of the stream of abrasive particles. The outlet (40) is configured for connection to a regulator for entraining the stream of abrasive particles into the stream of a blasting gas. The body (12) further comprises a window (50) within the conduit (30) for releasably coupling a sensor to determine a speed of the abrasive particles moving past the window (50).

Description

[0001] NIPPLE FOR MEASURING SPEED OF A STREAM OF ABRASIVE PARTICLES

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a nipple for measuring a speed of a stream comprising abrasive particles entrained in a stream of a blasting gas, a method of varying an abrasive particle density in a blasting gas, a method of measuring the flow rate of a stream of abrasive particles, a system for providing a stream of pressurised blasting gas, apparatus, a control system and a method of measuring a speed of a stream of abrasive particles.

[0004] BACKGROUND

[0005] It is known to provide a blasting apparatus in which particles of abrasive material are entrained in a stream of pressurised gas, typically air, and are expelled from a nozzle in a high-velocity jet directed onto a surface. The particles forcibly impact the surface to clean, abrade or otherwise prepare it for further treatment, such as painting, coating or bonding. This process is widely used in industrial applications, including surface preparation for construction, automotive maintenance, shipbuilding and restoration of metal, stone or concrete surfaces.

[0006] One commonly used abrasive material is sand, and when sand is employed, the process is often referred to as sandblasting. However, sand is not the only abrasive material suitable for blasting applications. Other materials, such as garnet, aluminium oxide, steel grit, glass beads and silicon carbide may be used depending on the specific requirements of the application. The choice of abrasive material often depends on factors such as the hardness of the target surface, the degree of abrasion required, environmental considerations and the need to minimise contamination or dust generation.

[0007] An important factor in ensuring the efficiency and effectiveness of a blasting process is the amount of abrasive material entrained in the stream of blasting gas. Consistent and optimal flow of abrasive material is desirable for achieving uniform surface treatment while minimising abrasive material consumption. Overuse of abrasive material can result in significant wastage, increased costs and unnecessary wear on the blasting equipment, while insufficient abrasive material may lead to suboptimal cleaning or abrading performance.

[0008] A person skilled in the art will appreciate that conventional systems suffer from the problem of being unable to provide precise metering of abrasive flow, particularly under varying operating conditions such as fluctuations in pressure, particle size inconsistencies and changes in nozzle configurations. Accordingly, conventional approaches suffer from a number of problems related to variations in the flow rate of abrasive particles.

[0009] It is therefore desired to provide an improved blasting system.

[0010] SUMMARY

[0011] According to an aspect there is provided a nipple for measuring a speed of a stream comprising abrasive particles prior to being entrained in a stream of a blasting gas, the nipple comprising: a body comprising a conduit extending from an inlet to an outlet, the inlet being configured for connection to a supply of the stream of abrasive particles and the outlet being configured for connection to a regulator for entraining the stream of abrasive particles into the stream of the blasting gas; wherein the body further comprises a window within the conduit for releasably coupling a sensor to determine a speed of the abrasive particles moving past the window.

[0012] According to various embodiment a nipple for measuring the speed of a stream of abrasive particles prior to their entrainment in a stream of blasting gas is provided which offers various advantages over conventional systems. In particular, a blasting system according to various embodiments is able to accurately measure the speed and flow rate of abrasive particles before they are mixed with the blasting gas. The incorporation of a window within the conduit for coupling a sensor allows for precise real-time measurement of particle velocity and flow rate as the abrasive particles move past the window. This capability ensures that the flow of abrasive material can be closely monitored and optimised, thereby improving blasting efficiency and surface treatment quality. Accurate speed measurement and flow rate determination is particularly beneficial for maintaining consistency in performance across varying operating conditions, such as fluctuations in pressure, particle size or material flow rates.

[0013] Another benefit according to various embodiments lies in the integration of the sensor window within the conduit which provides a streamlined and reliable measurement solution without requiring external disruptions to the abrasive flow. In particular, various embodiments facilitate direct particle speed measurement and flow rate determination in a controlled environment within the conduit, minimising inaccuracies caused by external interference or flow irregularities. This design ensures that the sensor provides highly reliable data for regulating the abrasive stream.

[0014] It will also be understood that the arrangement according to various embodiments is also compatible with existing blasting systems and hence is retroactive compatible. The inlet and outlet of the nipple may be configured for seamless connection to both the supply of abrasive particles and the regulator for entraining the particles into the blasting gas. This enables the nipple to be retrofitted into a conventional blasting apparatus without extensive modifications, providing an immediate and cost-effective solution for improving system performance.

[0015] By enabling precise measurement of particle speed and flow rate, various embodiments facilitate better control over the quantity and velocity of abrasive material delivered to the blasting stream. This results in several downstream benefits, including reduced material wastage, optimised abrasive consumption and improved cost efficiency. Controlling particle speed ensures uniform impact forces on the target surface, enhancing cleaning or abrasion results while avoiding excessive wear on equipment or over-treatment of surfaces.

[0016] The ability to measure particle velocity and flow rate prior to entrainment also enables the predictability and consistency of blasting performance to be improved. In industrial applications where precision is critical such as automotive surface preparation, aerospace maintenance or restoration work it is desirable to ensure consistent particle velocity so that a desired surface treatment is achieved uniformly and efficiently.

[0017] The approach according to various embodiments also enhances operational flexibility by accommodating a range of abrasive materials and flow rates. For example, the system may be utilised with sand, garnet, steel grit or other abrasive materials, and the nipple according to various embodiments allows an operator to monitor and adjust particle velocity based on the specific requirements of the application. This adaptability makes the arrangement according to various embodiments particularly suitable for a variety of industries and use cases, improving its versatility and commercial appeal.

[0018] Furthermore, the releasable coupling of the sensor to the window according to various embodiments provides practical benefits for maintenance and system longevity. Sensors can be easily installed, replaced or upgraded as needed without disrupting the operation of the blasting apparatus. This design minimises downtime and ensures that the system can continue operating at peak performance.

[0019] Overall, the system according to various embodiments is particularly advantageous in terms of providing an effective solution for measuring particle speed within a controlled conduit. The arrangement according to various embodiments enable improved accuracy, reduced material waste, enhanced compatibility with existing systems, and greater operational flexibility, all of which contribute to more efficient, cost- effective, and reliable blasting processes. It will be appreciated, therefore, that the present invention represents a significant advance in the art.

[0020] The nipple may further comprise a flow sensor releasably coupled with the window for measuring or determining a flow rate of the stream of abrasive particles moving past the window in use.

[0021] The window may be radially offset away from a substantially central longitudinal axis of the conduit.

[0022] The radial offset may be greater than zero and less than or equal to the radius of the conduit.

[0023] The window may extend substantially parallel to the longitudinal axis of the conduit.

[0024] The window may be substantially circular or ovoidal.

[0025] According to an embodiment the diameter of the conduit may be substantially equal to or greater than a width and / or diameter of a sensor window of the sensor.

[0026] The stream of abrasive particles through the conduit may, in use, be pressurised.

[0027] The stream of abrasive particles through the conduit may, in use, be gravity assisted.

[0028] The body may converge from an inlet diameter to a smaller conduit diameter.

[0029] The body may diverge from a conduit diameter to a larger outlet diameter.

[0030] The conduit diameter and the outlet diameter may be substantially equal.

[0031] According to an embodiment an inner inlet diameter of the body may decrease between the inlet and the conduit defining a convex inlet portion.

[0032] An inner outlet diameter of the body may increase between the conduit and the outlet defining a convex outlet portion.

[0033] The sensor may comprise a flow sensor or a flow rate sensor. The sensor may determine the flow rate by multiplying the instantaneous speed of the stream of abrasive particles with the substantially constant cross-sectional area of the conduit.

[0034] The inlet of the body may comprise a male threaded profile or a female threaded profile for fluidly connecting to the supply of the abrasive particles.

[0035] The outlet of the body may comprise a male threaded profile or a female threaded profile for fluidly connecting to a regulator for entraining the compressed gas with a stream of abrasive particles.

[0036] According to an embodiment an inner surface of the inlet and / or the outlet is smooth.

[0037] According to an embodiment an inner diameter of the inlet is substantially equal to an inner diameter of a blast pot or a conduit supplying the stream of abrasive particles from the blast pot.

[0038] According to an embodiment an inner diameter of the outlet is substantially equal to an inner diameter of a conduit supplying the stream of abrasive particles to a regulator which regulates the stream of abrasive particles being entrained into the stream of the blasting gas.

[0039] According to an embodiment the nipple may be integrally formed with a regulator for entraining abrasive particles with a source of compressed gas to produce the blasting gas.

[0040] According to an embodiment an inner diameter of the outlet may be substantially equal to an inner diameter of an inlet of the regulator.

[0041] According to an embodiment the regulator may comprise one or more valves.

[0042] According to an embodiment the regulator may comprise one or more valves in the form of one or more ball valves and / or one or more metering valves.

[0043] According to another aspect there is provided a method for varying an abrasive particle density in a blasting gas by measuring a speed of a stream of abrasive particle prior to being provided to a regulator for entraining into a stream of blasting gas, the method comprising: supplying a pressurised stream of abrasive particles through a conduit, the conduit having a window associated with a flow sensor; determining an instantaneous speed or flow rate of the stream of abrasive particles passing across or in proximity to the window; entraining the stream of abrasive particles into a stream of blasting gas; and varying the speed or flow rate of the stream of abrasive particles to alter the volume or flow rate of the stream of abrasive particles being entrained in the stream of blasting gas.

[0044] According to an embodiment the method further comprises varying the speed or flow rate by operating the regulator entraining the steam of abrasive particles into the stream of blasting gas. According to embodiments the regulator may be adjusted to increase or decrease the flow rate.

[0045] According to an embodiment the method further comprises varying the speed or flow rate of the stream of abrasive particles according to a correction factor which accounts for a frictional reduction between the stream of abrasive particles on the boundary layer moving past the window.

[0046] According to another aspect there is provided a method of measuring the flow rate of a stream of abrasive particles, the method comprising: directing a stream of abrasive particles through a narrowed conduit of a body, the conduit extending between an inlet and an outlet, and having a window radially offset from a substantially central longitudinal axis of the conduit; coupling a sensor to the body to measure a speed of the stream of abrasive particles through the window of the conduit; and multiplying the speed of the stream of abrasive particles with the cross-sectional area of the conduit.

[0047] According to an embodiment, the method further comprises applying a correction factor to account for a frictional reduction between the stream of abrasive particles on the boundary layer moving past the window.

[0048] According to another aspect there is provided a system for providing a stream of pressurised blasting gas by determining the flow rate of a stream comprising abrasive particles prior to being entrained in a stream of a blasting gas, the system comprising: a blast pot for storing abrasive particles and configured to couple to a nipple having a window; a sensor coupled to the window of the nipple for measuring the flow rate of the stream of abrasive particles passing the window from the blast pot through the nipple; and a source of pressurised air conveyed through a regulator, the regulator having an input fluidly coupled to the output of the stream of abrasive particles from the nipple; wherein the regulator is configured to entrain the stream of pressurised air with the stream of abrasive particles from the nipple to output a stream of blasting gas for use in blasting gas operations.

[0049] According to an embodiment the system comprises one or more sensors for measuring one or more measurements or characteristics of the system.

[0050] According to an embodiment the system comprises a display for outputting the one or more measurements or characteristics of the system.

[0051] According to an embodiment the display is configured to output an alarm when one of the one or more measurements or characteristics of the system moves outside a predetermined threshold.

[0052] According to an embodiment the system is configured to automatically adjust the speed of abrasive particle according to the one or more measurements or characteristics of the system.

[0053] According to an aspect there is provided apparatus configured to measure a speed or flow rate of a stream of abrasive particles prior to being entrained in a stream of a blasting gas, the apparatus comprising: a conduit through which a stream of abrasive particles are caused to flow in use; and a sensor configured to determine the speed or flow rate of the abrasive particles and produce an output.

[0054] According to an embodiment the conduit may have a keyhole shaped cross- sectional profile.

[0055] According to an embodiment the conduit may have a rounded-square shaped cross-sectional profile.

[0056] According to another embodiment the conduit may have a circular, oval, polygonal, curved or angular cross-sectional profile.

[0057] According to another aspect there is provided a control system comprising: apparatus as described above; and a controller configured to vary the flow of abrasive particles based upon the output from the sensor. According to an embodiment the controller in a mode of operation may be configured to optimise or otherwise control the flow rate of abrasive particles for performing a desired task.

[0058] According to another aspect there is provided a method of measuring a speed of a stream of abrasive particles prior to being entrained in a stream of a blasting gas, the method comprising: causing the stream of abrasive particles to flow through a conduit; and using a sensor to determine the speed or flow rate of the abrasive particles and produce an output.

[0059] BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Various embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawing in which:

[0061] Fig. 1 is an isometric upper view of a nipple according to an embodiment;

[0062] Fig. 2 is a cross sectional view of the nipple of Fig. 1 ;

[0063] Fig. 3 is a cross sectional view of an alternative nipple having convex inlets and outlets according to an embodiment;

[0064] Fig. 4 is a cross sectional view of an alternative nipple having concave inlets and outlets according to an embodiment;

[0065] Fig. 5 is an isometric upper view of a nipple having an alternative offset according to an embodiment;

[0066] Fig. 6 is an exploded view of a nipple according to various embodiments connected in line with a blast pot and a regulating device for dispersing abrasive particles into a stream of pressurised air;

[0067] Fig. 7 A shows a side view of an example system for entraining a stream of pressurised air with abrasive particles and incorporating a nipple according to an embodiment and Fig. 7B shows a front view of an example system for entraining a stream of pressurised air with abrasive particles and incorporating a nipple according to an embodiment;

[0068] Fig. 8 is an example output from the system display showing operating ranges and alerts or alarms; Fig. 9 is an example output from the system display showing operating ranges and alerts or alarms;

[0069] Fig. 10 is an example output from the system display showing operating ranges and alerts or alarms;

[0070] Fig. 11A shows a plan view of a nipple according to an embodiment having a keyhole shaped profile, Fig. 11 B shows a cross-sectional view of the nipple, Fig. 11C shows a front view of the nipple, Fig. 11 D shows a side view of the nipple and Fig. 11 E shows an isometric view of the nipple;

[0071] Fig. 12A shows a plan view of a nipple according to an embodiment having a rounded-square shaped profile, Fig. 12B shows a cross-sectional view of the nipple, Fig. 12C shows a front view of the nipple, Fig. 12D shows a side view of the nipple and Fig. 11 E shows an isometric view of the nipple; and

[0072] Fig. 13A shows a plan view of a nipple according to an embodiment having a convex longitudinal profile, Fig. 13B shows a cross-sectional view of the nipple, Fig. 13C shows a front view of the nipple and Fig. 13D shows a side view of the nipple.

[0073] DETAILED DESCRIPTION

[0074] Various embodiments of the present invention will now be described with reference to the drawings.

[0075] Fig. 1 shows an embodiment comprising a nipple 10 for use in a blasting gas system for measuring the speed of a stream of the abrasive particles prior to being entrained in a stream of blasting gas. The nipple 10 comprises a body 12 having an inlet 20 and an outlet 40. The body 12 further comprises a conduit 30 fluidly connecting the inlet 20 to the outlet 40. The body 12 is configured to supply a stream of abrasive particles from the inlet 20 to the outlet 40 through the conduit 30. The conduit 30 comprises a window 50.

[0076] The window 50 is configured to have a sensor (not shown) having a sensor window releasably coupled thereto. The sensor window may be configured to pass through at least a portion of the window 50 and may be directed through the window 50 so as to measure the flow of the stream of abrasive particles as it moves past the window 50.

[0077] The sensor may create a snug fit between the window 50 and a portion of the sensor housing. As will be described in more detail below, a gasket or rubber seal (or “O-ring”) may be positioned between the sensor and the nipple 10. This ensures that the abrasive particles cannot escape around the sensor window of the sensor.

[0078] The inlet 20 of the nipple 10 may be configured to connect to a source of abrasive particles, such as a blast pot. The blast pot may be arranged to store a volume of abrasive particles which are supplied through the nipple 10. The outlet 40 of the nipple 10 may be configured to connect to a regulator (not shown) prior to being entrained into a stream of blasting gas. The regulator may take a number of forms including, but not limited to, a valve device which will be discussed in detail below.

[0079] The nipple 10 may be releasably coupled to the sensor. When coupled, the sensor may be directed through the window 50 of the nipple 10 such that the sensor window is in contact with the stream of abrasive particles without impeding the flow of abrasive particles. The sensor is able to measure the speed of the layer of the stream of abrasive particles. The sensor may comprise a flow sensor such as an abrasive flow sensor. As the stream of abrasive particles passes through the nipple 10 in a dense phase, the flow sensor may be arranged to measure the layer of abrasive particles which is adjacent to the window 50 of the nipple 10. The flow sensor may take a reading in predetermined intervals to measure the instantaneous speed of the stream of abrasive particles. The flow sensor may take an average reading of a layer within the stream of abrasive particles, a single abrasive particle or a subset therebetween. Further limitations of such a measurement will be discussed in more detail below.

[0080] The body 12 of the nipple 10 may further comprise a support and mounting surface 14. The support and mounting surface 14 assists in the location, alignment, mounting and attachment of the sensor to the body 12 of the nipple 10. The support and mounting surface 14 may comprise a plurality of threaded connection points for releasably coupling the sensor to the body 12 of the nipple 10. Alternative methods such as clips, bindings, adhesives or other means known in the art for releasably coupling the sensor to the body 12 of the nipple 10 may be used.

[0081] The support and mounting surface 14 of the body further comprises a recess 16 for receiving a packing joint (or more commonly referred to as an ‘O-ring’). The recess 16 will substantially conform to the shape of the housing of the sensor and / or sensor window. The packing joint ensures the formation of an airtight seal between the sensor and / or sensor window and the window 50 and stream of abrasive particles. The sensor window may comprise a piece of transparent material. The sensor window may also be inherently scratch and / or abrasive resistant and / or comprises a scratch resistant coating. The sensor window may comprise a piece of sapphire glass.

[0082] Similar to principles of fluid dynamics, the outermost layer of a medium flowing through a conduit will experience friction on the boundary layer closest to the conduit 30 whereas the effects of that friction will be reduced further away from the boundary layer. Similarly, the speed of the layer of the stream of abrasive particles which passes by the window 50, and is being measured, is reduced due to the effects of friction. Therefore, in the preferred embodiment, the window 50 may be radially offset from a substantially central longitudinal axis of the conduit 30. In order to reduce the frictional forces, the inlet 20, the conduit 30 and / or the outlet 40 may be machined to be smooth.

[0083] The lateral offset may be designed to place the sensor in the best position to obtain a measurement which is indicative of the speed of the stream of abrasive particles most accurately without impeding the flow of the stream of abrasive particles through the conduit 30. The radial offset may be greater than zero as it may be desired to position the sensor sufficiently within the conduit 30 to make a measurement and to not impede the flow of abrasive particles. The radial offset may be less than a radius of the conduit 30. The radius being half the diameter of the conduit 30 without the window 50 located within the conduit 30.

[0084] Fig. 1 illustrates a lateral offset of the window 50 which is greater than zero but less than a radius or half the diameter of the conduit 30. The lateral offset of the window 50 may be approximately close to the substantially central longitudinal axis. Through extensive experimentation the inventors have found that while some abrasives may work with a larger lateral offset up to the radius of the conduit 30, a preferred lateral offset may be positioned between zero and the radius of the conduit 30. Furthermore, it may vary slightly based on a type of abrasive particle to be used. As such, the nipple 10 may be provided in a plurality of sizes configured for different abrasive types and uses.

[0085] The window 50 may extend along a length of the conduit 30 which may be parallel to the longitudinal axis of the conduit 30. The diameter of the conduit 30 may be substantially equal to or greater than width and / or diameter of the window 50. As the stream of abrasive particles is pressurised, the window 50 may be circular or ovoidal in shape. This shape reduces the focus of pressure within the conduit 30 from the corners or edges of other geometric shapes in which the window 50 may be provided in other or alternative embodiments. As such, the pressure will be uniformly distributed across the window 50. The window 50 may extend longitudinally along the length of the conduit 30 or a portion thereof. In some cases, the window 50 may be square or rectangular, however, this will be on a case-by-case basis and subject to several variables including, but not limited to, the pressure of the stream and / or the type of abrasive passing through the conduit 30.

[0086] In some embodiments a blast pot or other source of the abrasives being formed into the stream of abrasive particles may be positioned so as to have a greater potential energy than when passing through the nipple 10. Accordingly, the stream of abrasive particles may be gravity assisted. Therefore, the stream of abrasive particles may be pressurised and / or gravity assisted.

[0087] Fig. 2 shows a geometry of the inlet 20 and the outlet 40 of a nipple 10 having a body 14 and a conduit 30 therethrough according to an embodiment. The inlet 20 of the nipple 10 may be configured to converge from an inlet diameter 22 to a conduit diameter 32. Accordingly, the inlet diameter 22 may be greater than the conduit diameter 32. According to embodiments the outlet 40 of the nipple 10 may be configured to diverge from a conduit diameter 32 to an outlet diameter 42. Accordingly, the outlet diameter 42 may be greater than the conduit diameter 32. The inlet diameter 22 and the outlet diameter 42 may be equal. However, according to other embodiments the outlet diameter 42 may be larger or smaller than the inlet diameter 22.

[0088] Fig. 2 shows an inlet 20 which converges linearly from the inlet diameter 22 to the conduit diameter 32 to define a tapered inlet portion 24A. Fig. 2 also shows an outlet 40 which diverges linearly from the conduit diameter 32 to the outlet diameter 42 to define a tapered outlet portion 44A. The mounting surface 14, recess 16 and window 50 are also shown. The conduit 30 is shown having a longitudinal axis X.

[0089] Fig. 3 shows a preferred embodiment wherein the inlet diameter 22 converges to the conduit diameter 32 to define a convex inlet portion 24B. The outlet diameter 42 may be arranged to diverge from the conduit diameter 32 to the outlet diameter 42 to define a convex outlet portion 44B. The inventors have found that the convex shape is advantageous without impeding the flow of the stream of abrasive particles.

[0090] Fig. 4 shows an embodiment wherein the inlet 20 converges from the inlet diameter 22 to the conduit diameter 32 to define a concave inlet portion 24C. Fig. 4 also shows an outlet 40 which diverges from the conduit diameter 32 to the outlet diameter 42 to define a concave outlet portion 44C.

[0091] While the sensor measures a speed or flow rate of the stream of abrasive particles, the nipple 10 is ultimately intended to produce a uniform flow such that an accurate and reliable measurement of the speed or flow rate of the stream of abrasive particles can be measured by the sensor prior to being entrained in blasting gas. The geometry is specifically chosen to reduce varying particle velocity across a column of the stream of the abrasive particles such that the outside particles are substantially the same as the speed of abrasive particles in the centre of the column. In some cases, a correction factor as discussed below may be required in post processing to more accurately measure the speed of the stream of abrasive particles being entrained in the blasting gas. The cross-sectional area of the conduit 30 remains substantially constant throughout the lifetime of the nipple 10. In some embodiments, the body 12 may comprise one or more replaceable liners (not shown) which may cover the inlet 20, the conduit 30 and / or the outlet 40 so as to reduce and / or eliminate the need to replace the entire nipple 10. Rather, the one or more replaceable liners may be replaced in accordance with a predetermined maintenance program. Such maintenance program may be subject to a number of factors including, but not limited to, the material type, type of abrasive particles and hours of use. Accordingly, the volumetric flow rate may be calculated directly from the measurement of the speed of the stream of abrasive particles by multiplying the cross-sectional area and the instantaneous speed of the stream of abrasive particles. Once the abrasives have worn down the conduit 30 thereby increasing the cross-sectional area of the conduit 30, the nipple 10 may require replacement.

[0092] The nipple 10 is intended to be incorporated into a system between the source of abrasive particles, such as a blast pot and a regulator which regulates and entrains the abrasive particles into the stream of the blasting gas to be use for blasting operations. In the broadest scope, an outer diameter 26 of the inlet 20 and an outer diameter 46 of the outlet 40 may comprise a male threaded portion for threadedly engaging with a female threaded portion of a blast pot or a conduit connecting the stream of abrasive particles from the blast pot to the inlet 20. Accordingly, the inlet 20 may be fluidly connected to the source of the abrasive particles directly or through a first conduit (not shown) and the outlet 40 may be fluidly connected to the regulator directly or through a second conduit (not shown). In some embodiments, the inlet 20 and / or the outlet 40 may comprise a female threaded portion and the respective first and second conduits comprise the complementary male threaded portion(s). In alternative embodiments, the inlet 20 and the outlet 40 may be coupled to the respective components via other means known in the art such as quick release connectors, clips and / or clamps, such as tri clover clamps.

[0093] To avoid any additional and unnecessary shoulders which result in unusual wear on components, it is preferable that the inlet diameter 22 is substantially equal to the inner diameter of the blast pot or a conduit which supplies the stream of abrasive particles from the blasting pot to the nipple 10. Furthermore, it is preferable that the outlet diameter 42 is substantially equal to the inner diameter of the regulator or the conduit which supplies the stream of abrasive particles from the nipple 10 to the regulator and then onto the stream of blasting gas.

[0094] In the preferred embodiment, the nipple 10 may comprise a discrete component which may be coupled and retrofitted into existing blasting systems. In alternative embodiments, the nipple 10 may be integrally formed with a regulator which regulates the flow and entrainment of the stream of abrasive particles into the stream of blasting gas. As the regulator and the nipple 10 undergo similar wear and tear, it is likely that the lifetime between maintenance and / or replacement are similar. Furthermore, providing both components in a single unit may provide advantageous maintenance and manufacturing benefits while simplifying the system as a whole. In such instance, the outlet diameter 42 is preferably substantially equal to the inlet diameter of the regulator.

[0095] The regulator may be designed to control the flow and entrainment of the stream of abrasive particles into a stream of blasting gas. The regulator may be one or more valves which are positioned to disperse the stream of abrasive particles into the stream of blasting gas. The one or more valves may include, but are not limited to, ball valves and / or metering valves. The regulator may be a simple dispersion configuration known in the art. Alternatively, the regulator may be a more complex design which provides multiple valves which increase the points of dispersion for better entrainment of the stream of particles into the blasting gas. As such, the end user may be able to better fine tune the blasting gas for differing purposes to optimise the efficiency and use of the blasting gas.

[0096] Various embodiments further provide a method for varying an abrasive particle density in a blasting gas by measuring a speed or flow rate of a stream of abrasive particle being entrained in a stream of blasting gas. A pressurised stream of abrasive particles may be supplied to a nipple 10 as described above. The pressurised stream of abrasive particles is supplied through the conduit 30. The pressurised stream of abrasive particles may be streamed past the window 50 in the conduit 30. A flow sensor (not shown) may be coupled with the body 12 of the nipple 10 and may be directed through the window 50. The instantaneous speed of the stream of abrasive particles may be measured by the flow sensor as it passes across or in proximity to the window 50. The stream of abrasive particles may then be entrained into a stream of blasting gas through a regulator which disperses the stream of abrasive particles into the blasting gas. The regulator may be operated to vary the speed of the stream of abrasive particles. The operation of the regulator results in a pressure differential of the stream of abrasive particles which consequently varies the speed of the stream of abrasive particles. The regulator may be operated to vary the volume of the stream of abrasive particles being entrained into the blasting gas to optimise the blasting gas to be used by the user.

[0097] Embodiments also relate to a blasting system which incorporates a feedback system for optimising the speed of the stream of abrasive particles through the nipple 10. The volume of abrasive particles entrained in the stream of a blasting gas may be measured using known means. A comparison may be made between the expected and measured to determine a correction factor. The correction factor may be required for a number of reasons including, but not limited to, unaccounted for wear on the conduit 30 thereby altering the cross-sectional area of the conduit 30 and / or differences in the measured speed of the boundary layer of the stream of abrasive particles relative to an actual speed of the centre flow of the stream of abrasive particles from frictional reduction at the boundary layer between the stream of abrasive particles and the window 50. The system may use known methods such as a proportional-integral-derivative (PID) controller to optimise abrasive particle density in the blasting gas according to a user input for a desired abrasive density. The system may further comprise the necessary componentry to control the regulator and read / store sensor data to control the regulator according to a user input and / or sensor data. The componentry may further comprise a transceiver configurable to operate the system remotely. The transceiver may be configured to operate through WIFI, local area network (LAN), near field communication (NFC), Bluetooth, the Internet or other communication protocols known in the art.

[0098] A method for measuring the flow rate of a stream of abrasive particles in a dense phase prior to being entrained in stream of blasting gas is also disclosed. The stream of abrasive particles may be directed through a narrowed conduit 30 of the body 12 of the nipple 10 as described above. The sensor may be directed through a window 50 in the conduit 30. The speed of the stream of abrasive particles may be measured. As mentioned, the cross-sectional area of the conduit 30 is substantially constant. The cross-sectional area and the measured speed may be multiplied to determine the volumetric flow rate of the stream of abrasive particles. The calculation for volumetric flow rate may further be used to calculate mass flow rate by using the bulk density of the type of abrasive which is being used. While the bulk density remains constant for specific abrasive types, a user may be interested in the weight per unit of time, such as kilograms per hour, such that the user is able to anticipate or budget their needs for a particular project. An example calculation may be the speed of the stream of abrasive multiplied by cross-sectional area of the conduit multiplied by bulk density of the abrasive particles. In addition, the formula may further include a gain or other correction factor to account for friction or other inconsistencies between the measured speed and the actual speed of the stream of abrasive particles.

[0099] The system may further incorporate one or more pressure sensors for determining the pressure in the stream of abrasive particles and / or the stream of blasting gases. A pressure sensor may be located on one or both sides of the nipple 10. This may assist in determining blockages in the system and / or troubleshooting less than optimal performance of the stream of blasting gas.

[0100] Fig. 5 shows an isometric upper view of a nipple 10 having an alternative offset according to an embodiment of the present invention.

[0101] Fig. 6 shows an exploded view of a nipple 10 connected in line with a blast pot 90 and regulating device 92 for dispersing abrasive into a stream of pressurised air. Fig. 6 shows an exploded view showing an example system 100 incorporating a nipple 10. A blast pot 90 is arranged to store and provide a volume of abrasive particles. In the embodiment shown in Fig. 6 the nipple 10 may be positioned relatively lower than the blast pot 90 such that gravity, at least in part, assists in the feeding of abrasive particles through the nipple 10 to a regulator 92. The regulator 92 may comprise a Thompson (RTM) valve, however other valve and regulator means may be suitable. In alternative embodiments, regulation of the abrasive particles may be entirely, or at least in part, by a pressure differential across the nipple 10.

[0102] As seen in Fig. 6, the nipple 10 may be threadedly engaged at one end to an outlet of the blast pot 90. The outlet of the nipple 10 may be threadedly engaged with a connector 94. The connector 94 may comprise an extender or may provide a conversion from one type of thread to another for connecting to the regulator 92. The connector 94 may also comprise a shut off valve. As such, the shut off valve 94 can be activated when removing the regulator 92 e.g. when the regulator 92 is being replaced, maintained or otherwise removed to prevent the abrasive from discharging from the blast pot 90. In other alternative embodiments, the outlet of the nipple 10 may be connected directly to the regulator 92. A sensor 80 and O-ring seal 82 are also shown. Other embodiments are also contemplated wherein a shut off valve may additionally or alternatively be located upstream of the nipple 10.

[0103] Fig. 7 A shows a side view of a system 100 for entraining a stream of pressurised air with an abrasive incorporating a nipple according to various embodiments. As shown in Fig. 7A pressurised air may conveyed through a conduit 84 which is connected to a regulator 92. The regulator 92 entrains the abrasive particle being conveyed through the nipple into the stream of pressurised air to produce a stream of blasting gas.

[0104] A sensor 80 may form a snug fit between a window and a portion of the sensor housing. In the preferred embodiment, a gasket or rubber seal (or “O-ring”) may be positioned between the sensor 80 and the nipple. This ensures that the abrasive particles cannot escape around the sensor window of the sensor 80.

[0105] Fig. 7B shows a front view of a system 100 for entraining a stream of pressurised air with an abrasive incorporating a nipple according to various embodiments.

[0106] The system 100 may comprise one or more additional sensors, such as a pressure sensor 80A for measuring one or more measurements or characteristics of the system 100. For example, a pressure sensor 80A may be arranged to measure the pressure in the stream of pressurised air. The one or more sensors of the system 100 may also include sensors including, but not limited to, temperature sensors, humidity / dew point sensors, air flow sensor and abrasive level sensors. These sensors work together within the system to provide accurate display of the system status and alerts to the user when a measurement or characteristic falls outside of a desired or operational threshold.

[0107] The one or more characteristics or measurements of the system 100 may be a determination of the optimised flow rate for a specific abrasive particle. The specific abrasive particle may be input into the system 100 as a characteristic of the system to assist alone or in conjunction with other measurements, the ideal or optimal flow rate for the abrasive particle through the nipple. By way of a non-limiting example, where a particular abrasive particle is chosen in the system having a known density and the humidity sensor (if present) determines that a slower speed of the abrasive particle is required, the system 100 may adjust the regulator 92 to vary the output of blasting gas from the system 100. This is a non-limiting example which may extend to several scenarios which the person skilled in the art would appreciate is subject to the specific type of abrasive particle being used and one or more measurements (such as temperature, humidity, pressure, etc.) of the system 100 in a particular environment. The adjustments which the system may make will be determined by the particular abrasive particle being used.

[0108] The system 100 may further comprise a display 110 and a programmable logic controller 120. The display 110 may allow a user to view in real time different operating characteristics or measurements within the system 100. The display 110 may allow a user to display a number of key indicators for operating or monitoring the system 100. In some alternative embodiments, the display 110 may not be physically connected to the system 100 or proximate to the system 100. The system 100 may be configured for remote access and display 110 such that the display 110 is the user’s device which is accessed remotely from the system 100.

[0109] For example, the system 100 may measure the quantum of abrasive particles being used per unit of time for example kilograms per hour (kg / hr) across a time frame. If pressure in line 84 drops below a pre-determined threshold, the system 100 may prevent abrasive particles from being entrained via the regulator 92. In another example, the system 100 may anticipate problems via a feedback loop whereby the system 100 has a predetermined range of volumes of abrasive particle (kg / hr) being used at any given time and stores data for a set history of operation. There will be a baseline which the system 100 operates which the nipple will allow to be measured and determined. If the amount of abrasive particle exceeds or drops below the predetermined range, then the operator can identify and fix the issue of too much or too little of the abrasive particles being supplied to the regulator 92. According to various embodiments the comparison of actual flow rate to the optimal / baseline flow rate for the nozzle size and abrasive type combination may be input to the control system to allow the metering valve to be automatically adjusted to keep the flow rate within a desired / target flow rate. This can assist an operator with determining, amongst other things, whether there are any operational problems and / or unexpected wear on the equipment. As such, this may assist with preventative maintenance and preventing operation when the system 100 is outside of desired set of parameters.

[0110] The programmable logic controller 120 may further comprise a transceiver for local and / or remote communication via a local area network, Bluetooth, WiFi, the Internet, or other known communication means and protocols known in the art. The programmable logic controller 120 may also allow for connection to other systems 100 so as to compare one or more of the characteristics or measurements of the system 100. The display(s) 110 can then output one or more systems 100 measurements or characteristics to help identify any irregularities, certification date alarms, temperature alarms or active time on a particular hose. In alternative embodiments, each system 100 may comprise a plurality of the nipples coupled to the single blast pot and an accompanying regulator 92 such that the system 100 may provide a stream of blasting gas to a plurality of lines or hoses for use in blasting operation. As such, the display 110 can assist in identifying differences between lines or hoses to further assist in identifying any issues within one line or hose relative to another or to an overarching problem within the system 100 itself. In the preferred embodiment, the system 100 may be configured for use with multiple hoses for a number of different users.

[0111] In addition, the programmable logic controller 120 may be configured to process data on board, remotely or a combination of the two. Depending on whether the data collected will be processed onboard or remotely will determine the amount of data required to be transferred and / or the data type. In either instance, the programmable logic controller 120 may record total abrasive particles over a set period of time, for example 5-minute increments, and display this as a unit. As variances for any given second can be difficult to identify operational issues, having a sampling rate that is across a unit of time (i.e. every 5 minutes, 10 minutes, etc.) will make operational issues more identifiable.

[0112] Fig. 8 shows an output from the display 110 and shows data relating to blast time, weight of abrasive utilised and area covered for a plurality of different users. It will be understood that the output as displayed on the display 110 can be customised according to various different scenarios. According to various embodiments a user can look at the display outputs and quickly determine whether the system 100 is operating in accordance with expectations or whether some maintenance or correction may need to occur. In addition, any errors can be output to the display 110 as an alarm so as to ensure they are promptly attended to. The alarms may be entirely visual on the display 110 and / or include sounds and other external lights to attract the attention of the operator. The display 110 may have multiple tabs which are programmed through the programmable logic controller to provide the operator with the ability to adjust settings and / or view larger amounts of data on a smaller display 110. Fig. 9 shows an output from the display 110 and shows data related to the output from a plurality of blasting systems according to an embodiment and in particular the weight of abrasive dispensed per hour in units of kg / hour. It will be noted that a visual alarm has been generated indicating a low flow rate in one of the hoses which may be indicative of an error or the hose being used in a sub-optimal manner.

[0113] Fig. 10 shows an output from the display 110 and shows the current abrasive flow rate in units of kg / hour for a plurality of users together with the total abrasive usage in units of kg / day for a plurality of users.

[0114] Similar to the feedback system discussed above, a correction factor may be determined by measuring the actual abrasive particle density in the stream of blasting gas with the expected abrasive particle density in the stream of blasting gas. As above, the correction factor may be required for a number of reasons including, but not limited to, unaccounted for wear on the conduit thereby altering the cross-sectional area of the conduit and / or differences in the measured speed of the boundary layer of the stream of abrasive particles relative to an actual speed of the centre flow of the stream of abrasive particles from frictional reduction at the boundary layer between the stream of abrasive particles and the window.

[0115] Fig. 11A shows a plan view of a nipple 10 according to an embodiment having a keyhole-shaped profile. Fig. 11 B shows a cross-sectional view of the nipple 10, Fig. 11 C shows a front view of the nipple 10, Fig. 11 D shows a side view of the nipple 10 and Fig. 11 E shows an isometric view of the nipple 10. The keyhole-shaped nipple 10 as shown in Figs. 11 A-E may comprises a body having a keyhole profile that includes an enlarged rounded portion tapering to a narrower slot. This specific geometry may be intended to regulate the flow of abrasive material through the conduit, offering a defined pathway for particle velocity and distribution. The plan view shown in Fig. 11 A shows the overall profile, while the cross-sectional view in Fig. 11 B, the front view in Fig. 11C, the side view in Fig. 11 D, and the isometric view in Fig. 11 E collectively illustrate the dimensions and spatial arrangement of the nipple 10. The narrowing slot is designed to control the flow of abrasive particles while attempting to minimise turbulence and pressure drop across the conduit.

[0116] Fig. 12A shows a plan view of a nipple 10 according to an embodiment having a rounded-square shaped profile. Fig. 12B shows a cross-sectional view of the nipple 10, Fig. 12C shows a front view of the nipple 10, Fig. 12D shows a side view of the nipple 10 and Fig. 12E shows an isometric view of the nipple 10. The rounded-square shaped nipple, as shown in Figs. 12A-E, comprises a profile that combines a square geometry with rounded edges. This design improves the flow of abrasive material by promoting smoother velocity distribution while reducing turbulence. Fig. 12A shows the plan view of the rounded-square profile, whereas the cross-sectional view in Fig. 12B, the front view in Fig. 12C, the side view in Fig. 12D, and the isometric view in Fig. 12E provide further views of the profile of the nipple 10. The rounded edges ensure a smoother transition of particles through the conduit, minimising stagnation zones and facilitating uniform plug flow across the sensor area.

[0117] Both geometries were tested using glass bead abrasives which were selected for their consistent particle size and reliable flow characteristics. The tests aimed to measure particle velocity, flow consistency and accuracy of the abrasive material discharged through each geometry. The results demonstrate that the rounded-square shaped nipple delivers superior performance in terms of flow consistency and accuracy when compared to the keyhole-shaped nipple. Specifically, the rounded-square profile exhibited less variability in the measured flow rates, indicating a more uniform distribution of abrasive particles. By contrast, the keyhole profile, while effective in controlling flow, showed greater deviations in flow consistency, particularly at higher flow rates. The narrower slot geometry of the keyhole profile appears to contribute to intermittent disruptions in flow, which may lead to inconsistencies in particle velocity.

[0118] The rounded-square geometry offers several advantages over the keyhole profile. The smooth transition of particles through the conduit reduces turbulence and prevents jamming, ensuring consistent flow rates. The rounded edges minimise areas of stagnation where abrasive particles may accumulate, further promoting smooth and uniform flow. The reduced variability in particle velocity enhances the precision of flow measurements, improving the overall reliability and performance of the system. In contrast, the keyhole-shaped nipple may be better suited to applications where a more controlled or restricted flow pathway is required.

[0119] The results from the tests demonstrate that the rounded-square shaped nipple geometry provides more reliable and accurate flow characteristics. This improved consistency contributes to optimised system performance, reducing material wastage and ensuring uniform delivery of abrasive particles. The analysis highlights the advantages of the rounded-square design for enhancing flow measurement accuracy and operational efficiency in abrasive flow systems, as demonstrated in the comparative results summarised in Table 1 below.

[0120] Table 1

[0121] Further testing showed that the rounded-square nipple geometry as shown in Figs. 12A-E significantly improved flow consistency and accuracy for a range of different orifice discharge sizes. The results, as shown in Table 2 below, indicate that this design increases the empty annulus flow zone, which reduces intermittent jamming and promotes smoother flow of abrasive material. The improved flow characteristics result in a more uniform velocity distribution and enhanced plug flow consistency across the sensor area. This consistency is reflected in the reduced percentage errors observed during the testing process, showing the design’s effectiveness in optimising flow performance. In contrast, the key-slot geometry produced less reliable results, particularly at higher flow rates. Negative percentage errors recorded during testing suggest that flow irregularities, such as turbulence or uneven particle distribution, are more likely to occur with this geometry. These inconsistencies can reduce the accuracy of flow measurement and may result in suboptimal performance, particularly in demanding applications where precise flow control is essential.

[0122] The nipples were tested in stacked configurations comprising three nipples in series and the results which are presented in Table 2 below confirm that the multiple rounded-square nipples provided increasingly parabolic velocity profiles, supporting improved flow accuracy and measurement precision. The ability to stack the nipples without compromising performance highlights the adaptability of the design for applications requiring higher flow rates or enhanced flow monitoring. The parabolic velocity profile which was observed during the stacked testing aligns with theoretical predictions and supports the system’s ability to deliver consistent and reliable results.

[0123] Table 2

[0124] According to various embodiments the internal surface smoothness of the nipples may be maintained below 80 pm which is beneficial in terms of ensuring smooth particle flow and preventing the entrapment of smaller abrasive particles. It will be understood that smooth internal surfaces reduce resistance within the conduit, promoting efficient flow while minimising wear on the system. The use of 4140 nitrided tool steel, hardened to a depth of 0.3 mm, was beneficial in terms of resisting wear caused by the continuous flow of abrasive material. Other hard materials, such as hardened stainless steel, alternative tool steels or wear resistant ceramic materials may also be used depending on the specific operating conditions and requirements of the system.

[0125] The design according to various embodiments also allows for electronic actuation of the abrasive metering valve providing an option for automatic flow adjustments. Other embodiments are also contemplated wherein other methods of actuation may be utilised including mechanical, electro-optical or pneumatic actuation. This feature enhances the precision and control of abrasive material flow, enabling the system to respond dynamically to changes in operating parameters. Optimising the placement of the sensor window, positioned more than two orifice diameters above the discharge also minimises the effects of granular bridging and reduces “empty annulus” effects. This positioning ensures that vertical granular pressure effects are negligible, further improving flow measurement accuracy.

[0126] The combination of these factors demonstrates the effectiveness of the rounded- square nipple geometry in delivering superior flow performance, accuracy, and reliability when compared to the key-slot design. The improvements in flow consistency, surface smoothness, wear resistance, and sensor placement contribute to the overall optimisation of abrasive flow systems, ensuring efficient operation and reduced material wastage in a range of applications.

[0127] Fig. 13A shows a plan view of a nipple 10 according to an embodiment featuring a convex longitudinal profile, while Fig. 13B provides a corresponding cross-sectional view that highlights the longitudinal geometry of the conduit. The convex longitudinal profile facilitates smoother and more consistent flow of abrasive material through the conduit by reducing internal disruptions and promoting laminar flow. The profile introduces a slight outward curvature along its length, which helps guide the abrasive particles through the nipple with reduced turbulence. This feature minimises energy loss within the flow and ensures that the particles maintain their velocity as they travel through the conduit.

[0128] The front view, as shown in Fig. 13C, shows the inlet and outlet configuration of the nipple 10. The internal curvature of the conduit ensures a gradual transition of particles from the supply inlet through to the discharge outlet. The continuous and smooth curvature eliminates sharp edges or abrupt changes in direction, reducing the likelihood of particle stagnation, bridging, or jamming, particularly when operating at higher flow rates. Fig. 13D shows a side view and illustrates how the convex longitudinal profile contributes to the overall flow dynamics of the nipple. By incorporating this curvature, the design encourages uniform distribution of particles across the conduit cross-section, thereby improving flow consistency. This enhancement is particularly beneficial for applications requiring precise flow regulation and measurement, as it ensures that abrasive material is delivered to the blasting stream in a controlled and consistent manner. The smooth transition offered by the convex profile further reduces wear on the internal surfaces of the nipple, extending its operational lifespan.

[0129] The embodiments shown and described above provide various advantages over straight-profile conduits which may be prone to turbulence and irregular flow distribution, especially at higher velocities. A conduit having a convex longitudinal profile according to various embodiments has been found to benefit from enhanced efficiency of abrasive flow, minimal blockages and an overall improvement in the performance of the system. The design ensures that the abrasive material maintains a stable and consistent flow path, contributing to improved accuracy in flow measurement and enhanced operational reliability across a range of flow conditions.

[0130] It will be understood that the present invention is particularly advantageous where fine tuning of the blasting gas is desired. Further advantageous benefits include, but are not limited to, savings on the amount of abrasive material being consumed and the ability to measure the amount of abrasive material in a blasting gas without interfering with the stream of blasting gas.

[0131] While particular embodiments have been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the scope of the present invention.

Claims

Claims1 . A nipple for measuring a speed of a stream comprising abrasive particles prior to being entrained in a stream of a blasting gas, the nipple comprising: a body comprising a conduit extending from an inlet to an outlet, the inlet being configured for connection to a supply of the stream of abrasive particles and the outlet being configured for connection to a regulator for entraining the stream of abrasive particles into the stream of the blasting gas; wherein the body further comprises a window within the conduit for releasably coupling a sensor to determine a speed of the abrasive particles moving past the window.

2. A nipple as claimed in claim 1 , wherein the nipple further comprises a flow sensor releasably coupled with the window for measuring or determining a flow rate of the stream of abrasive particles moving past the window in use.

3. A nipple as claimed in claim 1 or 2, wherein the window is radially offset away from a substantially central longitudinal axis of the conduit.

4. A nipple as claimed in claim 3, wherein the radial offset is greater than zero and less than or equal to the radius of the conduit.

5. A nipple as claimed in any preceding claim, wherein the window extends substantially parallel to the longitudinal axis of the conduit.

6. A nipple as claimed in any preceding claim, wherein the window is substantially circular or ovoidal.

7. A nipple as claimed in any preceding claim, wherein a diameter of the window is substantially equal to or greater than a width and / or diameter of a sensor window of the sensor.

8. A nipple as claimed in any preceding claim, wherein the stream of abrasive particles passing through the conduit, in use, is pressurised.

9. A nipple as claimed in any preceding claim, wherein the stream of abrasive particles passing through the conduit, in use, is gravity assisted.

10. A nipple as claimed in any preceding claim, wherein the body converges from an inlet diameter to a smaller conduit diameter.

11. A nipple as claimed in any preceding claim, wherein the body diverges from a conduit diameter to a larger outlet diameter.

12. A nipple as claimed in any of claims 1-10, wherein the conduit diameter and the outlet diameter are substantially equal.

13. A nipple as claimed in any preceding claim, wherein an inner inlet diameter of the body decreases between the inlet and the conduit defining a convex inlet portion.

14. A nipple as claimed in any preceding claim, wherein an inner outlet diameter of the body increases between the conduit and the outlet defining a convex outlet portion.

15. A nipple as claimed in any preceding claim, wherein the sensor comprises a flow sensor or a flow rate sensor.

16. A nipple as claimed in any preceding claim, wherein the sensor is configured to determine the flow rate by multiplying the instantaneous speed of the stream of abrasive particles with the substantially constant cross-sectional area of the conduit.

17. A nipple as claimed in any preceding claim, wherein the inlet of the body comprises a male threaded profile or a female threaded profile for fluidly connecting to a supply of the abrasive particles.

18. A nipple as claimed in any preceding claim, wherein the outlet of the body comprises a male threaded profile or a female threaded profile for fluidly connecting to a regulator for entraining the compressed gas with a stream of abrasive particles.

19. A nipple as claimed in any preceding claim, wherein an inner surface of the inlet, the conduit and / or the outlet is smooth.

20. A nipple as claimed in any preceding claim, wherein an inner diameter of the inlet is substantially equal to an inner diameter of a blast pot outlet or a conduit supplying the stream of abrasive particles from the blast pot.21 . A nipple as claimed in any preceding claim, wherein an inner diameter of the outlet is substantially equal to an inner diameter of a conduit supplying the stream of abrasive particles to a regulator which is configured to regulate a stream of abrasive particles being entrained into the stream of a blasting gas in use.

22. A nipple as claimed in any of claims 1-20, wherein the nipple is integrally formed with a regulator for entraining a source of compressed gas to produce in use a blasting gas.

23. A nipple as claimed in to claim 22, wherein an inner diameter of the outlet is substantially equal to an inner diameter of an inlet of the regulator.

24. A nipple as claimed in claim 21 or 23, wherein the regulator comprises one or more valves.

25. A nipple as claimed in any of claims 21 -24, wherein the regulator comprises one or more valves in the form of one or more ball valves and / or one or more metering valves.

26. A method of varying an abrasive particle density in a blasting gas by measuring a speed of a stream of abrasive particle prior to being provided to a regulator for entraining into a stream of blasting gas, the method comprising: supplying a pressurised stream of abrasive particles through a conduit, the conduit having a window associated with a flow sensor; determining an instantaneous speed or flow rate of the stream of abrasive particle passing across or in proximity to the window; entraining the stream of abrasive particle into a stream of blasting gas; and varying the speed or flow rate of the stream of abrasive particles to alter the volume or flow rate of the stream of abrasive particles being entrained in the stream of blasting gas.

27. A method as claimed in claim 26, wherein the method further comprises varying the speed or flow rate by operating the regulator entraining the stream of abrasive particles into the stream of blasting gas.

28. A method as claimed in claim 26 or 27, wherein the method further comprises varying the speed or flow rate of the stream of abrasive particles according to a correction factor which accounts for a frictional reduction between the stream of abrasive particles on the boundary layer moving past the window.

29. A method of measuring the flow rate of a stream of abrasive particles, the method comprising: directing a stream of abrasive particles through a narrowed conduit of a body, the conduit extending between an inlet and an outlet, and having a window radially offset from a substantially central longitudinal axis of the conduit; coupling a sensor to the body to measure a speed of the stream of abrasive particles through the window of the conduit; and multiplying the speed of the stream of abrasive particles with the cross-sectional area of the conduit.

30. A method of measuring the speed of a stream of abrasive particles as claimed in claim 29, wherein the method further comprises applying a correction factor to account for a frictional reduction between the stream of abrasive particles on the boundary layer moving past the window.31 . A system for providing a stream of pressurised blasting gas by measuring a speed of a stream comprising abrasive particles prior to being entrained in a stream of a blasting gas, the system comprising: a blast pot for storing abrasive particles and configured to couple to a nipple having a window; a sensor coupled to the window of the nipple for measuring the speed of the stream of abrasive particles passing the window from the blast pot through the nipple; a source of pressurised air conveyed through a regulator, the regulator having an input fluidly coupled to the output of the stream of abrasive particles from the nipple; wherein the regulator is configured to entrain the stream or pressurised air with the stream of abrasive particles from the nipple to output a stream of blasting gas for use in blasting gas operations.

32. A system as claimed in claim 31 , wherein the system further comprises one or more sensors for measuring one or more measurements or characteristics of the system.

33. A system as claimed in claim 31 or 32, wherein the system further comprises a display for outputting the one or more measurements or characteristics of the system.

34. A system as claimed in claim 33, wherein the display is configured to output an alarm when one of the one or more measurements or characteristics of the system moves outside a predetermined threshold.

35. A system as claimed in any of claims 32, 33 or 34, wherein the system is configured to automatically adjust the speed of abrasive particle according to the one or more measurements or characteristics of the system.

36. Apparatus configured to measure a speed or flow rate of a stream of abrasive particles prior to being entrained in a stream of a blasting gas, the apparatus comprising: a conduit through which a stream of abrasive particles are caused to flow in use; and a sensor configured to determine the speed or flow rate of the abrasive particles and produce an output.

37. Apparatus as claimed in claim 36, wherein the conduit has a keyhole shaped cross-sectional profile.

38. Apparatus as claimed in claim 36, wherein the conduit has a rounded-square shaped cross-sectional profile.

39. Apparatus as claimed in claim 36, wherein the conduit has a circular, oval, polygonal, curved or angular cross-sectional profile.

40. A control system comprising: apparatus as claimed in any of claims 36-39; and a controller configured to vary the flow of abrasive particles based upon the output from the sensor.41 . A control system as claimed in claim 40, wherein the controller in a mode of operation is configured to optimise or otherwise control the flow rate of abrasive particles for performing a desired task.

42. A method of measuring a speed of a stream of abrasive particles prior to being entrained in a stream of a blasting gas, the method comprising: causing the stream of abrasive particles to flow through a conduit; and using a sensor to determine the speed or flow rate of the abrasive particles and produce an output.

Images