Plastics for cryogenic and high temperature applications

by Vinal Cass

Because polymer technology has experienced a major evolution, plastic materials have the ability to resist and perform in extreme conditions in relation to the temperature. All the high temperature polymers must include specific characteristics in order to lift up to the manufacturers’ requirements and standards. These characteristics have the goal to control the behavior of plastics in environments that present hotter and colder temperatures than ever anticipated and include creep resistance, exceptional wear properties, excellent resistance to hot water, thermal stability, high and low thermal conductivity, good sealing traits.

Characteristics of plastics at extreme temperatures

Plastics that present high resistance to extreme temperatures are very useful for various applications that demand superior mechanical properties and involve speeds or loads. If the plastic encounters moving parts, it must prove to wear resistance and low friction while withstanding various chemicals. The creep resistance represents a trait that helps to maintain tight seals while low stiffness is essential for mating surfaces. Moreover, plastics are perfect for electrical insulation. The multitude of polymers available provides irreproachable fire resistance and dielectric strength. Of course, manufacturers have performed multiple tests in order to meet the highest electrical standards. Because plastics offer low thermal conductivity at extremely cold temperatures, they can be used as part of physics research equipment.

Material selection for high temperatures application

Considering that the high temperature poyurethane will be used in high temperatures environments, manufacturers must analyze data concerning the material properties. The main factors they always keep in mind are degradation, thermal expansion, strength and modulus, stress relaxation and creep. Manufacturers must assess and control thermal degradation of polymers, which might degrade after a long period when facing high temperature environments. In comparison with metals, plastics materials are more vulnerable when it comes to thermal expansion meaning that they change in the area, volume and shape in response to drastic temperature change. That being said, manufacturers must ensure that dimensional changes between metal parts and plastic parts do not lead to a malfunction. When exposed to extremely hot temperatures, plastic material become soft, this means that they lose strength and modulus. For this reason, the importance of examining mechanical properties cannot be neglected. Apart from losing strength and modulus at high temperatures, plastics present higher stress relaxation and creep strain, factors that need to be taken into account during the production process.

Material selection for cryogenic applications

Plastic materials are also exposed to cryogenic temperatures, not only in extremely hot environments. When producing plastic components for this type of situation, manufacturers ensure that the plastics present a low thermal expansion and ductile behavior. The adequate thermal conductivity is imperative when dealing with heat transfer. Plastics wear differently when in cold environments so if they must be produced for bearing, choosing a material with low friction and excellent wear properties at cryogenic temperatures becomes essential. In certain industries including aircraft and spacecraft, the temperature level varies. This means that plastics must function perfectly throughout the respective temperature range. Obviously, various considerations appear when using plastics at different temperatures.

Learn how to maintain your ultrasonic cleaner

by Tye Stirling

If you already own an  silent-sound cleaner, it means that you had the time to become familiar with its functions and applications. Obviously, you cannot deny the benefits this product provides. In short, you have the possibility to maintain your household items of all shapes and materials shiny and new but have you ever thought about the machine? What do you do to maintain it? It may sound ironic the fact that you need to clean your cleaner and indeed, Hilsonic Ultrasonic Cleaners are designed to last in time but if you do not observe certain instructions and you do not take precautions, your personal safety could be at risk, not to mention that you will damage the machine. If you want to benefit from the efficiency and performance of your ultrasonic cleaner for years to come then you have to learn certain things and make time to apply them.

What you need to do

In order to function, the ultrasound cleaner needs an adequate solution and by now, you should know to avoid solvents and use water-based detergents because it represents the best option. Do not neglect changing the filtration system because it will improve  performance of this device by eliminating contaminants from the cleaning detergent. Before you proceed to clean the items, you should wipe greasy or heavily contaminated parts because even though the machine will remove all the dirt without problems, it will deposit on the bottom of the tank or in the filtration system. Even though you do not have to change the detergent every time you use the ultrasonic cleaner, you do have to drain it occasionally in order to clean out the tank. Keep in mind that all the grease, rust, bacteria, pigments, oil and so on accumulate at the bottom of the tank. You can just rinse it with clean water or wipe it with a rag. Do not forget to unplug the machine before you attempt to drain the solution because water combined with electricity could lead to severe damages. This may seem a detail but it holds a lot of importance.

What you should not do

If you do not want to damage the ultrasonic cleaner or your health, then you have to avoid certain actions. You should not use bleach or any products that contain harsh chemicals under any circumstances because this will affect not only the machine but also your items. Keep flammable liquids like alcohol far away from the area because they could cause an explosion or a fire. Avoid putting your hands into the supersonic cleaner during its functioning without wearing gloves because you skin could irritate and cause a feeling of discomfort. The machine usually comes with a basket for smaller items so you should use it and avoid placing the items directly on the bottom of the tank because it will lead to cavitation erosion. Do not attempt to repair the ultrasonic cleaner on your own. You do not have the necessary knowledge and you could do more harm than good. Ask the help of a professional who knows how to work high voltage machines.

Everything you need to know about gear pumps types

by Ethelbert Cyprian

Gear pumps are the most common positive displacement devices. They are used in almost every industry in which dense liquid transfer is required. There are two major types of gear pumps internal and external. Both these types are explained as under:

Internal gear pumps

Internal gear pumps have two types of gears. One is known as drive and the other is known as an idler. Thin and thick liquids are pumped at the same speed using this pump. With a large density range there are many applications which use internal gear pumps. This type of pump also has a high range of temperature and the variation is also great. The end clearance has single point due to which the temperature alteration is handled. The internal pump has clearance which can also be altered. The clearance factor is one which allows the internal gear pumps to work with high efficiency. There are several other factors which are associated with clearance. The pumping and density of liquids are made more efficient if the clearance value is altered.

Advantages of internal pumps

There are several advantages which are associated with internal gear pumps. Some of these are as follows:

  • The internal gear pumps are self-priming.
  • Such pumps can also run dry for small intervals
  • The rotation is multi-dimensional which means that internal gear pumps can also be used for other purposes.
  • The internal pumps are very reliable and are easy to install. The maintenance cost is also close to zero which means that over cost reduction is likely to increase of this pump is used.
  • These pumps require no technicalities for operation. Even a novice user can be deployed to operate these pumps as their structure is too easy to understand.

External gear pumps

As compared to internal gear pumps the external ones are applied in a large number of industries. The main applications of external pumps are oil stations, gas pumps and large food industries. There are many types of external gear pumps. Some of these are as follows:

  • Spur
  • Helical
  • Herringbone

The spur type pumps offer rough passage of fluids as compared to helical and herringbone types. Mostly herringbone types are used as they have less sound and the smooth passage is allowed. Another astonishing fact is that the large external pumps operate slowly as compared to small pumps. The shafts of external gear pump also allow support from both ends. They are ideal as they work in line with the hydraulic mechanics. Precision is another factor which external pumps offer. The internal tight clearances allow preserving precision factor.  Operators enjoy full control over fluid transfer which makes it most used the device in many industries.

Advantages of external gear pumps

  • These devices have high speed and work very swiftly
  • The less sound make them ideal for all environments
  • The design can be customized and a wide range of fluids can be pumped
  • The pressure as compared to all other types is high and offers precise measurement of liquids

Understanding Contingent Fee Model

by Bevis Eddy

The legal services market is characterised by asymmetry of information that exists ex ante, before signing contract signing a contract between the customer and the lawyer. At least two types of such information asymmetry can be distinguished: the first is manifested in the fact that the client when of the contract, is aware of the possibility of obtaining compensation to a greater extent than the lawyer, the second type of information asymmetry is explained by the fact that a lawyer knows the law than the customer.

Let’s consider the first type of information asymmetry. Customer must select the type of contract to be signed with the lawyer and chooses from hourly wages or contingent compensation.

The most common way of remuneration of a lawyer is an hourly fee for its services. It is believed that the time spent by the lawyer adds value to the services provided. There is another way to pay for such services – contingent consideration (contingent fee). Contingent consideration is an agreement between a lawyer and client, enshrined in the Treaty, according to which lawyer’s compensation depends on the outcome of the case.

Contingent fee is traditionally a matter of acute disputes. In the US, such contracts are usually used by lawyers of the plaintiffs and rarely by defendants’ lawyers. However, in many other countries with common law and civil law, they are banned or severely restricted. Until recently, Germany and Spain were the only countries of continental legal family, where conditional fee lawyers were allowed. In 1995, a kind of contingent consideration was permitted in England. In England, the roots of the prohibition of contingent consideration can be found in medieval legal conflicts that were the tools of a power struggle between the feudal nobility and the crown. The purpose of the ban was to prevent the contingent consideration litigation.

Nowadays England takes advantage of contingent fee system in its modified form to the full extent with numerous firms and agencies. The latest major legal adjustment was adopted in 2013, heralding the era of occupying the web by legal agencies. The map of companies involved in this sphere of legal services has not undergone drastic changes according to Solicitors Guru, perhaps, one of the largest hubs for licensed legal enterprises. Forster Dean is one of the largest UK no win no fee and motoring solicitors running a good number of offices throughout the country:

  • Birkenhead (Wirral)
  • Chorley (Lancashire)
  • Crewe (Cheshire)
  • Eccles (Greater Manchester)
  • Ellesmere Port (Cheshire)
  • Hanley (Staffordshire)
  • Harpurhey (Greater Manchester)
  • Leigh (Greater Manchester)
  • Liverpool
  • Liverpool (Bootle)
  • Liverpool (County Road, Walton)
  • Liverpool (Huyton)
  • Liverpool (Old Swan)
  • Liverpool (Tuebrook)
  • Newcastle-under-Lyme (Staffordshire)
  • Oldham (Greater Manchester)
  • Preston (Lancashire)
  • Rochdale (Greater Manchester)
  • Runcorn (Cheshire)
  • St Helens (Merseyside)
  • Stafford (Staffordshire)
  • Stockport (Cheshire)
  • Walsall (West Midlands)
  • Warrington (Cheshire)
  • Widnes (Cheshire)
  • Widnes – Conveyancing Department (Cheshire)
  • Wigan (Greater Manchester)

The remuneration of lawyers depends on the amount of compensation received by the client, so the contingent consideration creates a direct incentive for the lawyer to work for the benefit of the client. The more effort the lawyer makes, the greater the reward is likely to be, just like the remuneration is increased when a worker’s performance gets considerably increased. But the attorney client unlike manager at work, cannot evaluate the work of a lawyer, and contingent consideration ensures that the lawyer will work for the customer. Contingent consideration is designed to protect the client from a lack of information on the quality of the services acquired, and unite the interests of the lawyer and the client in aspiration for a positive income. If you have any questions about that concept then try to find more details about no win no fee legal costs agreements in special issues.