#graphite ring

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Graphite seal spare parts

The need for spare parts is limited, as the graphite blocks and wire ropes are interchangeable between the inlet and outlet seals. The graphite blocks for the FLSmidth graphite seal are designed to ensure long life and optimum performance while keeping the required maintenance to a minimum. 

The expected wear on the graphite blocks is 5-8 mm per year, which amounts to an expected lifetime of 3-5 years depending on conditions. The wire is designed to run for a full production campaign. The mechanical and thermal properties of graphite make it an ideal sealing material. The carefully selected material means that the graphite blocks are very hard and resistant to wear, yet flexible enough to conform to mating faces, thus ensuring a tight seal. 

The low coefficient of friction and the self-lubricating properties of graphite make it ideal for application where normal lubricants cannot be used. It also extends the graphite blocks’ lifetime. Even high temperature application is not a problem for graphite due to its dimensional stability under wide temperature variations and its low coefficient of thermal expansion. 

Furthermore, graphite is highly resistant to chemicals, corrosion and oxidation. FLSmidth graphite blocks are manufactured in highly specialised workshops using CNC equipment, which ensures high precision tolerance and a smooth surface finish.

Inlet cooling The inlet cooling system consists of a fan and a closed isolated ducting system to cool vital sealing components. The cooling air is distributed to the rear flange and the air casing attached to the kiln riser. The air will escape into the atmosphere.

Outlet cooling The outlet cooling system is separated into two independent systems – one for the kiln shell and nose ring cooling and one for the graphite cooling. The graphite cooling is designed to maintain the temperature of the graphite blocks below oxidization temperature and secures the flatness of the flanges. 

The closed rectangular cooling duct attached to the rear flange is cooled on a continuous basis, whereas part of the cooling air will be used to protect the graphite blocks from reaching high temperatures. The graphite cooling system includes a fan, a pneumatically operated shut-off valve, temperature probes and a local control panel. The cooling duct and bottom part of the shovel chamber has a cone to avoid duct accumulation before the graphite.

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The Need for the Bearing

Ball Bearings

Introduction

Ball bearings are used widely in instruments and machines in order to minimize friction and power loss. While the concept of the ball bearing dates back at least Leonardo da Vinci, their design and manufacture have become remarkably sophisticated. In the following, we shall review their basic characteristics.

Types of Ball Bearings

"A typical deep-groove ball bearing designed for high-speed operation is shown in Figure 1. In this bearing, the separator serves to keep the balls from rubbing against one another as is piloted on the inner race OD. Alternatively, the separator may be piloted by the rolling elements or by the outer race ID. Where rotative speeds are low, the separator often is omitted. The rolling elements may take many forms — cylinders, balls, tapered rollers, barrels, or very slim rollers known as needles — and the whole bearing name is generally taken from this form.

Ball Bearings

There are several types of ball bearings that fit specific needs. The deep-groove ball bearing, Figure 2(a), is the most versatile. Radial loads and thrust-load capacities may be approximately equal in this bearing. When it has the proper separator, it is very good for high-speed operation. At low speeds, no bearing separator is required; at intermediate speeds, a ball-control separator of steel-ribbon construction is adequate; while the ultimate high-speed performance is obtained with a race controlled (or piloted), fully machined separator.

Bearing Selection

Bearing selection represents a compromise among many factors including the nature of the application, performance requirements and cost. A useful bearing-selection chart, which summarizes the principal considerations involved, has been given by A.O. DeHart and is reproduced in Table 1.

Types of Bearings

There are many specialized types of bearings. Here are a few you might see in your everyday life while making awesome stuff:

“Normal” Radial Ball Bearing – What someone would normally think of as a bearing, with two concentric metal circles separated by little metal balls. These simple bearings can be found in everything from skateboards to drills.

Pillow Block Bearing – These bearings are a radial load bearing encased in a housing that can be attached to a surface parallel to the axis of rotation. Cam Follower Bearing – A radial load bearing with a threaded rod attached to it. Generally meant to ride on a cam to cause linear motion, these could have other interesting applications.

Ball Bushing (Linear) Bearing – This type of bearing is used extensively to allow for the smooth motion of 3D printer and CNC router heads. Their purpose, unlike the other bearings here, is to restrict radial motion, while allowing smooth linear motion.

Automotive Wheel Bearing – These are generally taperer roller bearings, allowing for both radial and axial load to be overcome. Thrust Bearings – These have many uses (especially automotive), but lazy susans and bar stools are what immediately come to mind as easy examples of their use. They could also be useful for anything else that needs to rotate smoothly, like a camera panning device.

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Graphite Lubricants

Graphite is one of three allotropic forms of the chemical element carbon; the other two are diamond and amorphous carbon. Graphite crystallizes in the hexagonal system. 

The carbon atoms are strongly bonded together in sheets. Because the bonds between the sheets are weak, graphite shows lower shearing strength under friction force. Thus it can be used as a solid lubricant and has become one of the traditional and primary solid lubrication materials.

Natural Graphite Natural graphite is usually found in association with feldspars, mica, quartz, pyroxene, rutile, pyrites, and apatite. Natural graphite is subdivided into three types: flake graphite, crystalline graphite, and cryptocrystalline graphite.

Flake Graphite Flake graphite occurs in metamorphic rocks uniformly distributed through the body of the ore or in concentrated lens-shaped pockets. Carbon concentrations vary.

Graphite lubricants for greasing forging tools, for stamping parts in steel, stainless steel, titanium, super alloy or aluminum and die forging and hot and warm extrusion.

For hot and warm forging operations, isothermal die forging, extrusion, CONDAT offers a large variety of graphite oils and greases.

The CONDAFORGE range offers a large choice of graphite lubricants:

with different graphite rates and sizes

with high-purity graphites

with viscosities ranging from liquid oil to grease

based on mineral, synthetic or vegetable oils

To cover most processes of stamping, die forging, drawing, extrusion... of steel, aluminum and brass.

Excellent properties of lubrication, separation, and mold-release

Low engraving and tool wear, low residues thanks to the use of very pure graphite and highly refined oils.

Grain size of the graphites from sub-micron to a few tens of microns, adapted to your processes (rate of work, material displacement)

High covering power and excellent wettability of tools

Reduced fire risk thanks to the selection of oils with a high flash point (minimum 200°C)

Stability of concentrates in storage

Product used pure or diluted in an oil

Highly refined oils without heavy metals and with reduced sulphur levels

All our products are compliant with the HS regulations in force.

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Insight of Ceramic Rope

Summary

Picture Courtesy: J.D.Jones

Ceramic Rope is basically a compression packing technique for very high-temperature duties. It is manufactured from an exceptionally stable fiber material that is soft, non-irritating, non-hazardous & is not limited by the World Health Organisation or European Union restrictions.

These heat resistant fabric material of rope are produced using advanced chemical fiber technology. They are spun into a flexible yarn, together with a low percentage of glass fiber and Inconel wire reinforcement.

Ceramic Rope, Tape, Cloth contains no organic agents or processing additives. It, retains its physical and chemical properties at very high temperatures and does not decompose, as happens with many normal ceramics.

Synonyms of product: Twisted Rope Round and Square Braid. Ceramic fiber rope

Description: Ceramic rope contains 15% organic carriers, which helps to establish the physical formation of products which has resistance about 750 °F (400 °C). These ropes are produced by twisting multiple plies of ceramic fiber wicking together. Standard 3-ply twisted rope is relatively soft and low in density and is the most economical choice.

HD 9-ply twisted rope provides increased compression resistance and strength and is much higher in density (about 50% denser) than 3-ply twisted rope. Both ropes are also available with covering of Inconel wire mesh, which drastically increases resistance to mechanical abuse.

Application: Compression packing of Ceramic Fiber Product Hi-Temp is recommended for very high-temperature static sealing duties or slow rotary applications. It replaces ceramic yarn packing and radiation seals on BOS plant, and ceramic packings and vessel lid seal on secondary steelmaking plant.

Other examples include door seals for furnaces at steelworks, protective surfaces, and stem gland sealing on valves handling very high-temperature gases.

Ceramic rope resists Hi-Temp include braided insulation sleeves, ladder tapes, twisted ropes, lagging ropes, blankets and paper, and woven cloth.

Features: Non-hazardous heat resistant fiber construction 1000°C for constant duties, with excursions to 1100°C A competitively priced alternative to normal ceramic fiber packings Good chemical compatibility

Advantages: Nontoxic, nonhealth hazardous and environmentally friendly. Longer life due to strength at optimum working temperature. High thermal insulation properties ensure a friendly working atmosphere. Noncombustible and electrically nonconductive (nonmetallic). Increase the safety of plant personnel and improves productivity. Although ceramic rope performs the same function as fiberglass rope, its properties are different. First of all, the aluminosilicate seal is much more tolerant to high temperatures. It can be installed in places where constant temperatures reaches up to 1260°C or 2300°F. It can also withstand hot flushes up to 1800°C or 3272°F. In contrast with fiberglass, a braided ceramic rope has a square cross-section which significantly simplifies its installation and makes it stick better to the surface.

Conclusion Though ceramic rope isn’t as strong as fiberglass rope, it is often selected because of its superior temperature resistance. Ceramic rope can withstand high temperatures usually up to 2300°F / 1260°C. In addition to having low thermal conductivity, ceramic rope is recognized for being lightweight, and fire resistant.

Square braided ceramic rope is available in diameters starting from 1/4” to 3.0”. Twisted rope is lightweight and easily conformable, while braided rope is stronger and denser.

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Compression packing and sealing

Summary Compression packing is an ancient technology dating back over 5000 years. Boats and ships used a rudder as a steering mechanism. Compression packing is now an integral part of the mechanical industry. Where there are machines, there will be compression packing. Ancient sailors, using the top technology of the day, would take pieces of clothing, sailcloth, and rope, cover it animal fat or wax and stuff it into the gap around the shaft.

Picture Courtesy: J.D.Jones

What is Compression Packing Compression packing is a sealing process where a gland along the top ring is tightened, and the packing compressed onto the surface to be sealed. Applications also include packing for other materials like valves, pumps, and rotating equipment. Most of the compression seals feature a braided, twisted, plaited, or laminated construction.

Controlling fluid loss is essential to the successful operation of mechanical equipment used in fluid handling. Various methods are applied to control leakage at rods, or valve stems and other functional parts of equipment requiring containment of liquids or gases. The oldest and still most common of these sealing is compression packing.

Compression packings find their major use in the process industries (e.g., petrochemical,pharmaceutical, chemical, pulp & paper, steel mills) and the service industries (e.g., utilities,marine, water, sewage, fossil / nuclear power plants).

How compression packing works The proper function of compression packing used in rotating or reciprocating pump service normally depends on a fluid film between the surface of the moving component of the equipment and packing for lubrication. Sources of this fluid film are either the self-lubricating properties of advanced packing material, the leakage of the fluid pumped, the built-in lubricants in liquid, solid, or combination form, or an external lubricant supply.

On equipment start-up, built-in lubricants may be released from the packings by gland pressure to provide initial lubrication and sealing. During service, continuous fluid film lubrication is provided by ongoing adjustment of the gland pressure and any combination of these sources: the built-in lubricants, the packing material, the pumped service fluid, or the external lubricant.

The advances give packings the following notable properties: - High pressure and vacuum capability - High and low (cryogenic) temperature capability - A broader range of chemical resistance - Less abrasive effect on mating surfaces - Improved dimensional stability in ring or rope form - Improved sealing capability - Better abrasion resistance

Compression Packing Seal Selection Compression packing seals consist of different fibers, construction, and lubricants that provide resistance to frictional heat or act as a fluid barrier to voids that are present in braided materials. Among the all sealing material, the proper selection of a packing seal is dependent on the operating condition of the equipment.

Compression Packing Seal Specifications Fibers: aramid, carbon/graphite filament, fiberglass, fiber-infused, flax, synthetic, PTFE

Construction: braid over braid, braid over the core, lattice braid, square braid, die formed, mandrel cut. Temperature Range: -328°F to +1200°F (depending on style) High Pressure : 500 PSI rotary, 4500 PSI valve

Conclusion Compression packing used in various instruments like umps, rotating or reciprocating service, normally depend on a fluid film between the surface of the moving member of the equipment, and the packing, for lubrication. Compression packing used in valves where there is slow or infrequent motion, and those used in static operations, are required to seal without any leakage. Various impregnates may be used to assist in this function.

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Need for Insulation in the Thermal Industry

Summary

Thermal insulation is basically the use of a material with low conductance to reduce the energy flow across another material. The insulation acts to reduce the flow of heat, thus it must have a high resistance being the inverse of conductance. There are three main types of insulative effect.

Picture Courtesy: J.D.Jones

Resistive Resistive insulation also called as bulk insulation, insulates against the transfer to heat simply through its resistance to conduction. Because air has one of the highest resistances to conduction, the best resistive insulators are those that trap small pockets of air within themselves.

Reflective Reflective insulation works by reducing the radiative heat transfer. The ability of a material to absorb infrared radiation depends on both the nature and color of its surface.

Capacitive Capacitive insulation has directly no effect inflow, which is when temperatures are relatively constant on each side of a material. If the temperature on either side fluctuates, then only capacitive insulation effects become important.

Section of an insulation The type of insulation you use will be determined by the nature of the space that you plan to insulate. The important part is to know that the different forms of insulation can be used together. For example, roll insulation can be added over loose-fill insulation, or vice-versa.

Most commonly used materials are-

Fiberglass Fiberglass is the most common insulation used in recent time. Fiberglass is able to minimize heat transfer. Fiberglass is made out of finely woven silicon, glass powder and tiny shards of glass are formed, so these can cause damage to the eyes, lungs, and even skin. Need to be very careful while working with fiberglass.

Mineral wool Mineral wool refers to several different types of insulation. First, it may refer to glass wool which is fiberglass made from recycled glass. Second, it may be called rock wool which is a type of insulation made from basalt.

Cellulose This type is perhaps one of the most eco-friendly forms of insulation. Cellulose is usually made from recycled cardboard, paper, and other similar materials and comes in loose form.

Polystyrene Polystyrene is a waterproof thermoplastic foam which is an excellent sound and temperature insulator. It comes in two types, expanded (EPS) and extruded (XEPS).

Ceramic rope

Ceramic ropes are used in high temperature gasketing, packing, sealing, and insulation applications. ... Ceramic rope can withstand high temperatures up to 2300°F / 1260°C. 

Conclusion In a simple word, I can say that Insulators work as protectors. They protect from heat, sound and the passage of electricity. Thermal insulators, sound insulators, and electrical insulators are used for various reasons. All thermal insulation materials work on a simple principle that is either heat moves from warmer to colder areas or vice versa.

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Types of Graphite Ring

SUMMARY

Here we can say that flexible graphite ring are slope type seal packing ring, that is also known as flexible graphite packings, the main uses of flexible graphite tape or flexible graphite preparation of packing, by molding it into many kinds various sizes of ring products. High temperature resistant and also in the name of V packing ring.

Graphite ring are mainly in the die formed compressed graphite rings. They are very flexible and highly impermeable to gases as well as liquids. We can say that the advantage of graphite rings in long life with no hardening deformations. Installation as well as removal of graphite ring which can be done without danger of damage on the faces of sealing. Therefore they can be excellent substitute for some types of metal O-rings.

Main Features

For increasing the compressive capacity of the packing ring, it can be wrapped within  the product 304 stainless steel mesh to increase the compressive capacity. It can also be in the upper and lower end of the product, with stainless steel sheet to wrap.

These kinds of slope seal ring with corrosion resistance, high temperature performance. But it also has good self-lubricating, good flexibility, small torque characteristics.

It has a very good resilience, and also you can say that the chemical stability can effectively play a sealing effect.

Advantages of Graphite Rings:

Resistant to high temperatures and pressures

Highly resistant to wear

Resistance to chemical aggression

Impermeable to most gases and liquids

It is very easy to install and low maintenance

As per our experts we can say that graphite rings are very easier to install without risking damage to sealing faces, and with self lubricating properties, a graphite ring setup is almost maintenance free.

The sealing rings in high density Graphite which is made by pressing the tape of expanded graphite.

These kinds of tapes are wound in a spiral within a suitable mold and then by pressing to obtain the required degree of density, these kind of manufacturing process make sure that a high elasticity constant, no further adjustment are required.

This type of gasket is used for the sealing of pumps and valves; thanks to the high stability over time of its mechanical characteristics, by its ability not to suffer thermal shock can be used with excellent results in use with special fluids such as steam, diathermic oils, strong acids with the exception of nitric and sulfuric acids at high concentrations.

There are many kinds of seals for maintaining a full line of flexible graphite materials who are also offering flexibility and stability for your application. You can say that flexible graphite is manufactured from mineral graphite which contains carbon content around 95% and 99%. Higher the percentage of carbon more will be its flexibility and hence the graphite will exhibit. All kinds of flexible graphite gaskets have excellent resistance to corrosive chemicals, high temperatures and high pressures. They also exhibit amazing thermal conductivity and also ability to securely seal. Graphite gaskets also offer a good resistance to abrasion and resistance to humidity. Flexible graphite gaskets are used in many industries for example; refineries, chemical and petrochemical plants, paper mills mines and other fields. They can be used in many other applications which mainly include EMI shielding, heat dissipation, industrial fluid sealing, lubrication, stress sensing, vibration damping, and other thermal, electronic and electrochemical applications.

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All You Need to Know About Ceramic Insulation

Summary

Ceramic insulation is made from needled high-temperature ceramic fibers and provides good quality lightweight high-temperature insulation up to 2300°F or 1260°C. Ceramic insulation is generally called high-temperature insulation wool and sometimes ceramic fiber blanket.

Ceramic insulation is commonly used in tube seals, furnace maintenance, fabric expansion joints, high-temperature gaskets, and industrial insulation blankets. Though ceramic insulation has good thermal resistance, it doesn’t provide as much strength and durability as a glass mat. It is also available in 6 pound or 8-pound densities.

                                                                              Picture Courtesy: JD Jones

Ceramic Fiber Insulation

Ceramic fiber products consist of thermally efficient high-temperature insulating materials that combines the advantages of low heat storage and complete resistance to thermal shock thus offers a broad range of thermal capabilities and physical features.

Ceramic Fibre Blankets

Ceramic Fibre Blanket is refractory fiber needled mat made from fibers. Being Zirconia stabilized every blanket are suitable for use upto 1260°C and 1425°C. A wide range of densities, chemistries, and thickness Fibre Blankets are available.

Application

Furnace & Kiln linings

High-temperature gaskets

Removable insulating blankets for steam and gas turbines

Low-velocity stack lining

Flexible high-temperature pipe insulation

Temporary repair of refractory furnace linings

Advantages

Low Shrinkage

Excellent Thermal Stability

Inorganic - Smoke-free

Excellent Thermal Shock Resistance

Low Heat Storage Capacity

Excellent Heat Strength

Low Thermal Conductivity

Ceramic Fibre Modules

Fiber modules are one of the best solutions for high-temperature insulation applications like industrial heaters, furnaces, and boilers.

These modules combine the insulation material advantages of ceramic fiber along with rapid furnace installation.

Application

Kiln and heater linings

High-temperature furnace

Reheating furnace

Bell annealing furnaces

Shuttle kilns / Tunnel Kilns

Process heaters lining

Advantages

Individual module mounting enables replacement without

Faster installation

Superior to thermal stability and shock resistance

Reduced shrink compared to layered lining

Ceramic Fibre Boards & Shapes

These blocks and shapes are obtained by vacuum suction of a mixture of ceramic fibers with organic and mineral binders. These are self-supporting with excellent stability at high temperatures, having high resistance to thermal shock, chemical attack and maintain stability at high temperatures.

Advantages

Low heat storage

Excellent insulating performance

Resistance to thermal shock

Excellent thermal stability

Ceramic Fibre Paper

High-performance ceramic paper products are the preferred choice over the traditional fiberglass, textile and metal products for acoustical, thermal, or filtration management.

Application

Expansion Joints

Mould liners

Ladle lining backup

Induction furnace coil protection

Refractory Membrane in Chimneys & Scrubbers

Thermocouple insulation and Packing replacement for asbestos paper

Insulating gaskets

Advantages

Highly flexible & resilient

Good resistance to tearing

Very low thermal conductivity

Non-wetted by most molten nonferrous

Resistance to thermal shock

Uniform thickness & density

Conclusion

Ceramic fiber is a type of lightweight insulating product. It has a low thermal mass that means that it doesn’t retain heat, low thermal conductivity and is an extremely effective insulation material. Their high thermal shock resistance makes them suitable for applications where traditional refractories can’t be used. So-called Refractory Ceramic Fibre is made from high purity alumino-silicate materials. Ceramic fiber is produced by melting these products in an electric arc furnace, which is a stream that is poured and cooled to form the fiber strands from which the ceramic fiber products are then produced.