#flexible graphite

The formation of flexible graphite is an art and proves to be the best solution to maintain VOC levels to acceptable levels on valves and pumps. What starts as a ribbon pack also become custom size parts. If you want more information, tap on the link and Ask to Expert.

For years, polytetrafluoroethylene (PTFE) has brought a number of desirable properties for traditional ink and coating applications, such as broad spectrum chemical resistance, resistance to water and solvents, a slippery surface, resistance to degradation when exposed to UV light, unusually high molecular weight and melt point, and it did not flow above its melt point.

Development over its first three decades exploited the chemical resistance and stability of PTFE while further refining its handleability, processability and strength properties by copolymerizing with other monomers like hexafluoropropylene, ethylene or other fluorinated monomers.

Low molecular-weight PTFE micronized powders have been used for a variety of purposes, including to reduce the coefficient of friction of the film to aid mobility and to lubricate and protect surfaces from scratch and abrasion forces. To achieve low-molecular weight and friability has typically required irradiation to enable particle size reduction using conventional micronization techniques.

However, in recent years, PTFE has come under some scrutiny and driven the exploration of PTFE-alternatives.

Regulatory Actions Impact PTFE PTFE stability properties that have driven use in many applications also impact cradle-to-cradle policies. The irradiation process has been demonstrated to generate PFAS components, with PFOA and PFOS both classified as reproductive toxins and suspected carcinogens. While PTFE itself is not regulated, PFAS components are regulated in Europe (July 4, 2020 EU REACH restriction effective date) and regulations limiting the quantity of PFAS materials are pending in other regions of the world.

In this global regulatory environment, there are essentially two alternative approaches: use PFAS-free (compliant) PTFE or develop new products without PTFE.

Lubrizol is taking both of these approaches—PFAS compliant PTFE and PTFE-free alternatives—to have products in place before the July 4 restriction date in the EU. Formulations with reduced levels of PTFE have shown promise, as has a new non-halogen, proprietary material being used in place of PTFE.

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. 

What are the applications for hydraulic power packs?

Mobile hydraulic applications have recently been increasing so much with hydraulic power packs. Some applications are as follows; dump trailers, electric sanitation trucks, snowplows, telescopic logistics equipment, like the dock leveler, car tailgates, wing trucks, electric pushcarts, and electric pallet lifts. Other uses include car lifts, scissor lifts, electric operating tables, and special equipment on elevators. Compact hydraulic power units (HPU) work well at high pressure, with its low flow hydraulic system, small size, simple elements, and affordable price.

How many different types of hydraulic power units are there? These units include; single-acting hydraulic power units, double-acting hydraulic power units, power units, and other complex special effects work. In the motor voltage are DC hydraulic power units, and AC hydraulic power units. In the tank installation are vertical or horizontally mounted hydraulic power units. The valves are controlled by manual operation hydraulic power units, and electric control hydraulic power units.

What components do hydraulic power units components include? (HPU) Hydraulic power units are a hydraulic system with hydraulic actuators (hydraulic cylinders, hydraulic motors) connected to the control valve operation to achieve the operation of the equipment for the adopted oil pressure apparatus. Hydraulic power units come complete with a power section (electric motor, hydraulic pump), the control section (pressure valves, directional control valves, flow control valves), and the auxiliary section (couplings, manifold block, suction pipe, return pipe, tank, air breather, etc.).

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.

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