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Fighting against global warming and increasing greenhouse gas concentrations, the regimentation of CO2 emission are the justification for the European Commission to set up the European Directive 2005/32/EC. This and several amending directives describe a framework of eco-design requirements for energy using products asking for increased efficiencies. New standards and norms have been written and others have been updated which now need to be considered in new product engineering projects. Furthermore, energy costs are rising constantly and will continue to rise in the future.

Considering these aspects the design of modern furnaces has changed recently. New designed vacuum furnaces are operating much more efficient than older furnaces. Also modern steel degassing plants use more and more mechanical vacuum systems instead of energy-wasting steam ejector systems. Also here, modern vacuum pumps and pump systems, designed to support these energy saving attempts, have proven their capabilities.

High reliability can be reached by using traditional technologies as e.g. oil-sealed rotary piston or rotary-vane pumps, roots blowers and diffusion pumps, but also also more modern technologies such as dry screw pumps already have a proven track record to work most reliable even under harshest conditions. Today’s standard dry pumps are screw pumps with variable pitch rotor design. Continues compression along the rotor length minimizes the energy demand. Older technologies with constant screw pitch or even dry pumps based on multiple stages of roots- or claw type rotors, have significantly higher power consumption due to design and pumping principle. But even the plurality of today’s screw-pumps with variable pitch differs a lot from each other. Most pumps of the 600 m³/h class demand app. 10 kW power at typical furnace operation pressures below 1 mbar, which is a clearly higher value as those of a comparable rotary-vane pump.

The Dryvac pump series of Oerlikon Leybold Vacuum are optimized with regard to the mechanical rotor design, the electrical motor concept and by selection of a perfectly matched build-in frequency converter.The achieved result in energy saving is substantial, as the pump only consumes 6.9 kW at 1 mbar, is even more energy efficient than a rotary-vane pump and therefore is the new bench mark for power consumption in the market. The build-in frequency converter also offers potential for additional savings and higher process control. Many process steps do not require “full-power” suction speed, especially during operation at rougher pressures, e.g. during carburizing.

Soft start and ramping functionality can be realized with the variable frequency drive. Chamber pressure can be controlled by varying the rotational speed. The customer can even realize a process specific “standby condition” considering certain valve positions to save for example the volume of supplied Nitrogen. Next to these environmental issues, the modern design of the Dryvac eliminates sensitive components as shaft- seals or couplings which clearly increase robustness and reliability of the pump.

Modern designed pumps improve the energy consumption, but several measures can also improve the situation with traditional pumps. Oil-sealed pumps and roots-pumps need to be equipped with newest standard IE2-motors and can be operated with frequency converters to deliver just as much suction speed as required. Oil-diffusion pumps can be equipped with innovative control-systems which can identify the actual power demand and regulate the power supply of the heaters accordingly. These measures diminish the power consumption of a diffusion pump by more than 30 per cent.

Centrifugal process pumps may perform a relatively straightforward task but they are often working in hostile and stressful operating conditions. As a result, they can often fail prematurely – resulting in lost productivity from unplanned downtime.

Improved pump reliability, reduced maintenance and lower energy consumption can all be achieved by ensuring that a process pump is operating at optimum speed and efficiency.

Common problems
One of the main problems that can occur in engineering components is cavitation, which is a significant cause of wear, notably where pressurised liquids are being handled. This makes pumps highly susceptible, especially if they are required to start quickly. It occurs when a liquid is subjected to rapid changes of pressure, causing the formation of cavities in the lower pressure regions of the liquid. When entering high pressure areas, these bubbles collapse on a metal surface continuously, causing cyclic stressing of the metal surface and resulting in surface fatigue of the metal.

Cavitation in pumps generally occurs in one of two forms: suction cavitation and discharge cavitation.

Suction cavitation occurs when the pump suction is under a low-pressure/high-vacuum condition where the liquid turns into a vapour at the eye of the pump impeller. This vapour is carried over to the discharge side of the pump, where it is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitation condition can lose either large chunks from its face or have small bits of material removed which will cause it to look spongelike. Both cases will cause premature failure of the pump, often due to bearing failure. Suction cavitation is often identified by a sound like gravel or marbles in the pump casing.

Discharge cavitation occurs when the pump discharge pressure is extremely high, normally when a pump is running at less than 10 per cent efficiency. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out. As the liquid flows around the impeller, it must pass through the small clearance between the impeller and the pump housing at extremely high velocity. This causes a vacuum to develop at the housing wall which turns the liquid into a vapour. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump housing. In addition, due to the high pressure conditions, premature failure of the pump’s mechanical seal and bearings can be expected. Under extreme conditions, this can break the impeller shaft.

The latest technology has improved the function of vacuum pumps and helped industries (such as dairy farming and medicine) keep up with the pace of a rapidly changing and evolving global market place.

Online PR News – 17-December-2009 – The Improved Functionality of Vacuum Pumps and Systems Benefitting Many Businesses.
Vacuum pumps and systems reduce the level of pressure (most often air), in a closed circuit, system or container. There are many applications for vacuum pumps and blowers (systems) that include some familiar (and some rarely thought of) situations. Some of these applications include:
• Air Conditioning and Heating- Heating and air conditioning vacuum pumps contain a vacuum pump to maintain adequate air pressure and exchange in the system.
• Surgical/Medical-Surgical Vacuum Pumps are used in a variety of medical procedures including the operating room and in dental procedures. Removal of blood and other wastes from the procedure area are one function of a surgical vacuum pump.
• Industrial Manufacturing-Industrial vacuum systems are responsible for tasks such as liquid retrieval, and air removal from packaging.
• Plastic Injection Molding Companies-Vacuum pumps are used to remove air from molds and prevent blistering of plastic manufacturing materials.
• Injection Molding Tooling
• Equipment and Machinery- Many types of industrial equipment and machinery use vacuum lines and pump systems to function properly and how intended.
• Agriculture-Milking makes great use of the vacuum pump for automated milking of cows, goats, even sheep occasionally. We would not be able to meet the demand for milk and milk products if vacuum pumps were not available for milking.
Understanding vacuum pumps and systems can be difficult. The Vacuum Pump Guide was created to help alleviate some of your confusion. Some vacuum pump systems are quite complicated and a thorough knowledge of their working parts is crucial to using them efficiently, no matter what procedure you may be completing.
Some advances that make vacuum pumps and systems perform even better are:
• Picking up of liquids.
• Ability to move very hot materials through the system
• Increased suctioning capabilities to better compact materials when packaging.
• Ability to handle explosive and caustic materials.
• The components are resistant to abrasion when manufactured with some of the newly developed materials.
The vacuum pump guide covers some other related areas:
• Specific types of vacuum pumps such as the turbo molecular pump and the liquid ring vacuum pump are detailed.
• How to locate and purchase surge vacuum pump parts both locally and on the internet are explained.
• How to perform maintenance and repair on certain vacuum pumps and systems is available at the Vacuum Pump Guide.
• Other associated industrial machinery such as injection and plastic molding is explained.
• The intricate internal workings of a vacuum pump and system help you to develop a good understanding of the process.
• Equipment for the containment of natural gas in cylinders and equipment to detect gas leaks before they cause harm or injury.
The Vacuum Pump Guide is an essential tool if you desire to learn about and comprehend the function and purpose of vacuum pumps, systems and similar equipment.

The vacuum pump is a genius invention that plays a role in many parts of our lives. Vacuum pumps are used in our air conditioning units, in our cars, in our airplanes, and even in some of the medical processes used today. Though it was a technology that took some time to develop, comparatively speaking, it is a technology that was well worth waiting for.

The initial vacuum pump was designed in the 1650’s by a man named Otto van Guericke. This pump created a vacuum by pulling gas molecules from a sealed space. Otto Guericke’s theory lay in the belief that if two pieces of a whole, say a sphere, were connected and the air was sucked out of the sphere, nothing would be able to cause the two halves to separate. His theory was proven correct and, initially the response was good, with more tests and demonstrations being performed throughout the 1650’s. Over time things trickled off, however. Vacuum pumps were still tested but not widely used because they did not produce enough suction.

In the late 1690’s a vacuum pump was patented in England. This pump was known as the Thomas Savery pump. Many modern pumps have been designed after this one pump.

Experimentation and testing with vacuum technology continued until 1855 when Heinrich Geissler created the mercury displacement pump, which was even better than the Guericke’s invention.

Fast forward a few hundred years to where vacuum pumps are a part of our everyday lives. As mentioned before, the technology took time to develop properly, nearly three hundred years, but it was well worth the wait. You’ll find vacuum pumps being used by firefighters in their rescue missions, by doctors administering radiotherapy, in freeze drying processes, and throughout sewage systems.

You’ll also find a bunch of different types of pumps, ranging from low and medium, to high pressure pumps. Low and medium pumps are more simply made. Medium pumps are used in aircraft as part of the heading and altitude systems while low pressure pumps are often part of the air conditioning units. High pressure pumps are usually those used in hydraulic systems. They are more complex than low and medium pressure and are usually made custom for each job they are required for.

Most of the history of the vacuum pump centers on testing and perfecting the science, building upon the discoveries of earlier inventors. Three hundred years is a long time to master the art of creating a vacuum pump, and the time has been put to good use. The pumps have been altered and perfected, and are now being put to good use.