Bristle blasting is a mechanical abrasion cleaning process that is performed on metallic surfaces by a brush-like rotary power tool. The tool consists of sharpened, high-carbon steel wire bristle tips that are designed with a forward-angle bend, i.e., the shank of the wire is bent in the direction of tool rotation. During operation, the rotating bristle tips are brought into direct contact with the metallic surface, whereby the bristle tips strike the surface with kinetic energy that is equivalent to processes that use grit blast media. This repeated contact of sharp bristle tips with the target surface results in localized impact, rebound, and the formation of craters, thereby simultaneously cleaning and coarsening the surface, while exposing a contamination-free base metal. [1]
The difference from conventional wire-brushing with an angle grinder lies first with the mounting of the bristles in the rotating brush. With a conventional rotary brush, the wire bristles are mounted rigidly in the hub, bristles sometimes being twisted or knotted in groups for extra stiffness. With bristle blasting, the wires are mounted resiliently in a flexible belt. As the brush rotates, immediately before contacting the work, rows of bristles are trapped behind a fixed 'accelerator bar' , [2] which causes them to bend backwards in their flexible mount. As the bristles pass the accelerator bar, they are released to spring forwards. The extra energy stored for each bristle when being flexed backwards is added to their kinetic energy when released, and when they impact the surface of the workpiece. This gives a more violent impact with the surface, thus greater cleaning power, compared to a simple rotary brush at the same speed.
As the geometry of the brush is also distorted from circular by the accelerator bar, the contact angle of the bristle tips with the surface is also nearer to perpendicular than the tangential contact of the circular rotary brush. This encourages a cleaning action and reduces the burnishing action that can be a problem with rotary brushes, where a surface is increasingly polished, but not truly cleaned of surface adherents. The steeper action of the tips encourages a pitting effect on the surface, which may be considered useful for further painting. [2]
The cleaning performance of the bristle blasting process is a consequence of synchronized impact of the bristle tips onto the target surface. The tool head with the bristle belt rotates at approximately 2,500 rpm. A so-called 'accelerator bar' detains the bristle tips and by releasing them increases their kinetic energy with which they strike the surface. Immediately after the bristles strike the corroded steel surface, they retract (rebound) from the surface ('single-impact'), which results in corrosion removal and a micro-indentation that exposes the sheer metallic surface. The multitude of such primary impact craters generates a texture and surface which in visual cleanliness and roughness (anchor profile) mimics those obtained by grit blasting processes. [2] The cleaned and coarsened surface is deemed favorable for the subsequent application and adhesion of protective films and industrial coatings. [3]
Bristle blasting tools are fabricated from high-carbon steel wires that protrude through a flexible circular belt. The belt, in turn, is attached to a rotating hub, which is powered by an electric or pneumatically driven spindle. The tool is lightweight, portable, and easily implemented by workers without the need for elaborate set-up or sophisticated safety apparatus. [4]
Bristle blasting is most frequently used for removal of unwanted films and layers of corrosion that can form on metallic surfaces. Common applications include cleaning, preparation, and refurbishment of iron and steel components that are used for fabricating bridges, ships, and pipeline systems. [5]
Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be coated acts as the cathode of an electrolytic cell; the electrolyte is a solution of a salt of the metal to be coated; and the anode is usually either a block of that metal, or of some inert conductive material. The current is provided by an external power supply.
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion.
A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. Two or more electrical contacts called "brushes" made of a soft conductive material like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings on the armature are connected to the commutator segments.
Cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. The sacrificial metal then corrodes instead of the protected metal. For structures such as long pipelines, where passive galvanic cathodic protection is not adequate, an external DC electrical power source is used to provide sufficient current.
A brush is a common tool with bristles, wire or other filaments. It generally consists of a handle or block to which filaments are affixed in either a parallel or perpendicular orientation, depending on the way the brush is to be gripped during use. The material of both the block and bristles or filaments is chosen to withstand hazards of its intended use, such as corrosive chemicals, heat or abrasion. It is used for cleaning, grooming hair, make up, painting, surface finishing and for many other purposes. It is one of the most basic and versatile tools in use today, and the average household may contain several dozen varieties.
Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals and composites. It entails striking a surface with shot with force sufficient to create plastic deformation.
In materials science, a metal foam is a material or structure consisting of a solid metal with gas-filled pores comprising a large portion of the volume. The pores can be sealed or interconnected. The defining characteristic of metal foams is a high porosity: typically only 5–25% of the volume is the base metal. The strength of the material is due to the square–cube law.
Fusion bonded epoxy coating, also known as fusion-bond epoxy powder coating and commonly referred to as FBE coating, is an epoxy-based powder coating that is widely used to protect steel pipe used in pipeline construction from corrosion. It is also commonly used to protect reinforcing bars and on a wide variety of piping connections, valves etc. FBE coatings are thermoset polymer coatings. They come under the category of protective coatings in paints and coating nomenclature. The name fusion-bond epoxy is due to resigning cross-link and the application method, which is different from a conventional paint. In 2020 the market size was quoted at 12 billion dollars.
A burr is a raised edge or small piece of material that remains attached to a workpiece after a modification process.
Thermal spraying techniques are coating processes in which melted materials are sprayed onto a surface. The "feedstock" is heated by electrical or chemical means.
A regenerative heat exchanger, or more commonly a regenerator, is a type of heat exchanger where heat from the hot fluid is intermittently stored in a thermal storage medium before it is transferred to the cold fluid. To accomplish this the hot fluid is brought into contact with the heat storage medium, then the fluid is displaced with the cold fluid, which absorbs the heat.
A wire brush is a tool consisting of a brush whose bristles are made of wire, most often steel wire. The steel used is generally a medium- to high-carbon variety and very hard and springy. Other wire brushes feature bristles made from brass or stainless steel, depending on application. Wires in a wire brush can be held together by epoxy, staples, or other binding. Wire brushes usually either have a handle of wood or plastic or are formed into a wheel for use on angle grinders, bench grinders, pistol-grip drill motors, or other power tools.
Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. A pressurised fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material. The first abrasive blasting process was patented by Benjamin Chew Tilghman on 18 October 1870.
Dog grooming refers to both the hygienic care and cleaning of a dog, as well as a process by which a dog's physical appearance is enhanced for showing or other types of competition. A dog groomer is a person who earns their living grooming dogs.
Surface grinding is done on flat surfaces to produce a smooth finish.
Eco pickled surface (EPS) is a process applied to hot rolled sheet steel to remove all surface oxides and clean the steel surface. Steel which has undergone the EPS process acquires a high degree of resistance to subsequent development of surface oxide (rust), so long as it does not come into direct contact with moisture. EPS was developed by The Material Works, Ltd., which has filed several patent applications covering the process. It is primarily intended to be a replacement of the acid pickling process wherein steel strip is immersed in solutions of hydrochloric and sulfuric acids to chemically remove oxides.
Soldering is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint.
A rotary union is a union that allows for rotation of the united parts. It is thus a device that provides a seal between a stationary supply passage and a rotating part to permit the flow of a fluid into and/or out of the rotating part. Fluids typically used with rotary joints and rotating unions include various heat transfer media and fluid power media such as steam, water, thermal oil, hydraulic fluid, and coolants. A rotary union is sometimes referred to as a rotating union, rotary valve, swivel union,rotorseal, rotary couplings, rotary joint, rotating joints, hydraulic coupling, pneumatic rotary union, through bore rotary union, air rotary union, electrical rotary union, or vacuum rotary union
The conservation and restoration of outdoor bronze artworks is an activity dedicated to the preservation, protection, and maintenance of bronze objects and artworks that are on view outside. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer.
In-water cleaning, also known as in-water surface cleaning, is a collection of methods for removing unwanted material in-situ from the underwater surface of a structure. This often refers to removing marine fouling growth from ship hulls, but also has applications on civil engineering structures, pipeline intakes and similar components which are impossible or inconvenient to remove from the water for maintenance. It does not generally refer to cleaning the inside of underwater or other pipelines, a process known as pigging. Many applications require the intervention of a diver, either to provide the power, or to direct a powered tool.