Friday, July 30, 2010

Mechatronics

An International Journal



A Journal of IFAC, the International Federation of Automatic Control





Mechatronics is the synergistic combination of precision mechanical engineering, electronic control and systems thinking in the design of products and manufacturing processes. It relates to the design of systems, devices and products aimed at achieving an optimal balance between basic mechanical structure and its overall ... click here for full Aims & Scope

Mechatronics is the synergistic combination of precision mechanical engineering, electronic control and systems thinking in the design of products and manufacturing processes. It relates to the design of systems, devices and products aimed at achieving an optimal balance between basic mechanical structure and its overall control. The purpose of this journal is to provide rapid publication of topical papers featuring practical developments in mechatronics. It will cover a wide range of application areas including consumer product design, instrumentation, manufacturing methods, computer integration and process and device control, and will attract a readership from across the industrial and academic research spectrum. Particular importance will be attached to aspects of innovation in mechatronics design philosophy which illustrate the benefits obtainable by an a priori integration of functionality with embedded microprocessor control. A major item will be the design of machines, devices and systems possessing a degree of computer based intelligence. The journal seeks to publish research progress in this field with an emphasis on the applied rather than the theoretical. It will also serve the dual role of bringing greater recognition to this important area of engineering.



Mechatronics publishes the following types of papers:



• Regular Articles should describe original research of high quality in the field of Mechatronics.



• Review Articles will generally be specially commissioned, however, suggestions for topics and authors are welcomed by the Editor-in-Chief



•Technical Notes provide rapid publication of important new contributions

Sunday, July 25, 2010

How to replace the mechanical seal on the pump pool filter



All filtration systems for pools and spas, involve the use of several pieces of equipment. One of the most important being your spa or pool filter pump. A mechanical seal is one of the key elements in the design of these pumps. The work of a mechanical seal is to prevent water leakage along the shaft of the pump.



Damage to pump seals swimming pool and spa, takes place due to overheating, vibration, and a sudden change of water pressure. There are some cases where the dirt is trapped between the seal faces. This can cause damage to the seal and causing a leak. Once you develop a leak on the pump you it does get worse, so the seal must be replaced.



Steps to replace your success seals pump shaft



Before the repair of any pool pump can begin, you must gather the necessary tools and spare parts needed to finish the job. Tools and resources include:



A pair of pliers.

A good set of ratchet.

A key small turbine.

A rubber hammer or a mall.

A set of screwdriver.

Some sand paper, emery cloth.

silicone lubricant.

A new assembly mechanical shaft seal. Make sure the correct model attached for your pump model. You can do this by consulting your owner's manual or the manufacturer of your pool pump.

A replacement joint for the pump.

Anti-Seize. To take the son of the motor shaft.



The replacement of your pump shaft mechanical seal



In general, follow all safety precautions at all meetings of any type of electrical equipment. Failure to do so may result in serious injury or death to you or others.



Before you start repairing your pump pool filter, you must disconnect all electrical power sources. Make sure you lock out and tag the main breaker. It is a further precaution, which will prevent injury to a person accidentally activating the switch.



Close the valves at the inlet and outlet access pump.To poor mechanical seal on your pool pump, you must remove the screws of four. These are the four bolts that hold the motor and mounting the wheel to the pump housing.



Hold the engine in both hands and shake from side to side slightly. This will allow you to successfully pull the engine and bracket assembly of the pump housing.

With your pliers or wrench, hold the extended end of the shaft (back end). This will prevent the shaft from moving.



Now, take your key and remove the impeller wheel of the pump shaft. If you do not have a wheel wrench handy, you can place an old cloth on the wheel and unscrew by hand. The cloth will help prevent you cut on the edges of the impeller. There is also another option, but it is a last resort. Use one of your cons wheel and tap it with your center of rubber. Always be careful not to crack or damage the turbine.



The seal plate should now be removed from the pump motor. This is done by removing four small screws holding it in place. Once the screws are removed, a free will, gently tap the seal plate engine.



Now, before removing the mechanical seal, please be aware of how it is originally installed. This will help in the installation of the pump shaft seal.Now again use a small screw drive flat to assist in the removal of the rotating component of the seal.



The fixed part of the seal is in the recess on the seal plate located on the motor bracket. To remove, turn the plate sealing more. The fixed part of the seal is now facing down. Place the tip of a screwdriver on the back of the pad and pat.



Use an emery cloth and a little water to clean the shaft / sleeve of the motor and seal the recess in the seal plate.



Place small amount of silicone lubricant on both the drive shaft and mechanical seal in the doorway. This lubrication allows the gasket to slip up a little easier. Make sure you install the two halves of the trim in the same manner as the original. Part ceramic white trim with black rubber cup, enters the plate seal. The glass finish should be facing you.



The other part of the mechanical seal (rotating part with the spring) is on the shaft. Only after the motor bracket is bolted in place. You must use extreme care here because you do not want to damage, scratch or dirty the face of your new mechanical seal.



Check the pump seal and if it is damaged in any way, replace it. Now, if your pool pump has a joint paper (centrifugal pumps), you might want to replace it. Indeed! Each time you remove the pump, the seal of origin usually fails to close. Before installing your new pump head gasket, you must remove all traces of the old. This will ensure proper seating of the new: for example, provide a good seal.



If you must replace the head gasket of the pump, insert the new between the two halves of your pump. Now, wind your pool pump in the reverse order that you removed.



Finally, open the valves of the pump suction and discharge pipes. Restore power and boot. Check for signs of leakage. There are some cases where a paper gasket is used, a small leak may be obvious, but once the seal is wet, it will create a good seal. In some cases, one or two more turns on the bolts on the pump is necessary. However, once you follow these instructions in your repair of the pump will be a success.



Usually the manufacturers of spa and pool pumps will recommend that you repair your own pump. This is to keep your warranty and to avoid injury. However, if your warranty and you're a little short of money, I say go ahead and do your own repairs. But always, always use your trial to demonstrate safety first. Manufacturers also prefer people who are qualified to work on their products, to do so.

However, on the other hand I think the instructions right you or I can successfully replace a pump mechanical seal. Well! We'll put a lot of money and process the learning experience is priceless

Friday, July 23, 2010

Lever Mechanism

The gear – lever mechanism is based on the slot - crank motion (like Geneva wheels) configuration. When oscillated motion is applied at the input gear (by an oscillated lever about fixed axis A -not shown), which meshes with the second gear, it forces it to oscillate in opposite direction. On the second gear is mounted rigidly a crank whose pin slides along slot of output lever which turns freely about axis A. Output lever transmits reciprocating motion to an intermediate link (not shown) which is connected to the driven part of the mechanism. Thus oscillation of input gear (and lever) is converted into different oscillation of output lever.


When the crank’s (rigidly attached at the second gear) symmetry plane coincides with the output lever’s symmetry plane in the neutral position, then the output oscillation angle is smaller than the input one. If we rotate the second gear counterclockwise (like a planet) around the input gear and maintain the same neutral position of the output lever, then the oscillation characteristics will be modified. Under a suitable selection of the crank length and the position of the second gear, the output lever will perform a double oscillation (attention, two complete oscillations of smaller angle during the input one).



The advantages of the gear - lever mechanism against the cam actuated is the lower cost of gear trains, and the adaptability to different positions of the input lever (remember that a lever oscillates the input gear) or the input shaft. It can be used reversely (but not in many positions) in order to produce a larger oscillation angle. At the configuration shown at the figures there is a formula for calculation of the angular displacement of the output lever b corresponding to crank angle a, which is equal (if the gear train ratio is one) to input gear angle.

Tuesday, July 20, 2010

Circular Compression Anastomosis

The authors report the preliminary results obtained in animal and clinical experimentation of a new mechanical device for circular anastomosis which they have developed. It is a gun that places an apparatus consisting of three polypropylene rings that, through the compression among them of the severed edges of the bowel, realize a sutureless anastomosis and are spontaneously evacuated. Fifty-eight colonic anastomoses were performed in dogs with this device; 23 stapled colonic anastomoses were also executed concurrently. Forty-four animals underwent a relaparotomy to remove the colonic specimen containing the anastomoses. Bursting pressure and the histologic features of the anastomoses were evaluated at different time intervals after operation. A good healing of all compression anastomoses was observed, thereby allowing them to initiate the experience in humans. Thirteen anastomoses (6 colorectal extraperitoneal, 1 colorectal intraperitoneal, 5 colocolonic, 1 ileorectal) were performed at the 1st Surgical Department, Milan University. One subclinical leakage (7.7%) spontaneously healed in a few days. No stenoses were observed.

Thursday, July 15, 2010

Mechanical Ventilation

Natural ventilation can be a key element of cooling strategies in many climates. Mechanical ventilation can also be part of cooling strategies (that's the case of the ceiling fans), but they involve also a rather different type of ventilation to exhaust stale...

More than just opening windows


In its simplest version natural ventilation is opening windows and doors, to benefit from breezes. But natural ventilation - cross and stack ventilation - can be part of a more elaborate approach for cooling our homes, involving features like home design, landscape, placement and size of openings, etc

Cross ventilation


When people open windows in opposite sides of the house to cool the indoor temperatures, they are using cross ventilation.




Stack (Convective) Ventilation: the «Chimney Effect

Natural stack ventilation (also called convective ventilation) uses a physics natural fact: the chimney effect or air buoyancy...


In natural stack ventilation, the warmer indoor air rises up from lower living areas and escapes through the upper openings of the building, causing cold air infiltration through windows or other lower openings…




climates and natural ventilation


Natural ventilation loses much of its power in hot-humid climates. Unlike mechanical air-conditioning, natural ventilation doesn’t reduce the humidity of incoming air, making the cooling process rather ineffective during periods of high humidity.

Higher humidity conditions, requires greater air-speeds and greater ventilation to provide comfort. And the breezes and shaded spots may not provide those pre-conditions.

If natural ventilation can’t provide significant comfort, and you live in hot climates, you may try a closed building-air-conditioning approach for some parts of the house

Deflecting the wind: Wing Walls and casement windows


Wing walls are vertical panels placed next to windows to intercept and direct the colder breezes into the house, via open windows or other openings. They are specially useful to deflect breezes, when they don't blow in the more convenient pattern (see image).

Casement windows can work as wing walls. Just have into account the way the casement windows open relatively to the dominant breezes, in order to direct the wind into the home. Casement hinges can be located on the left-hand side or on the right-hand side, taking into account the dominant direction of the breezes...



Mechanical ventilation


Mechanical ventilation involves 1) ceiling fans and other assisted-fan ventilation, but also 2) exhaust fan ventilation (simple kitchen exhaust fans or bathroom exhaust fans, and the more sophisticated HRV and ERV ventilation).


While natural ventilation or ceiling fans are part of cooling strategies, the exhaust ventilation systems main goal is to exhaust stale air, replacing it with fresh air (which is particularly important in cold and temperate climates, in tightly insulated homes).

Natural ventilation, cracks and air leakage


Air leaks and gaps were traditional ways of supplying fresh air to homes, in cold climates. They acted like vent openings, contributing to the ventilation needs. But since these gaps and sources of air leaks are also a source of heating and cooling losses, and since many modern well insulated and airtight houses do not provide that source of outside air, mechanical ventilation becomes crucial for reasons that have nothing to do with cooling goals.

Ventilation & Health

In many cold climates or even in some mild ones, gaps and leaks in the walls or next to windows and doors are a source of contaminants such as formaldehyde or radon, which can cause health problems; besides, these same gaps can also be a source of moisture and lead to mold growth and cause damages…

Monday, July 12, 2010

Mechanical ventilation.

Among intensive care unit patients who require mechanical ventilation, use of a silver-coated endotracheal tube resulted in reduced incidence of pneumonia associated with ventilators, according to a report in the August 20 issue of JAMA. Ventilator-associated pneumonia is associated with longer hospital stays, increased health care costs and infection with antibiotic-resistant pathogens, according to background information in the article. It is likely to develop when pathogenic bacteria colonize the aerodigestive tract or when patients breathe out contaminated secretions. "Prevention strategies often focus on modifiable risk factors for colonization and aspiration and can successfully reduce ventilator-associated pneumonia rates, but no single strategy completely eliminates ventilator-associated pneumonia," the authors write. "Adherence to prevention guidelines is variable due to costs and lack of education, resources and leadership."

Silver has displayed antimicrobial activity in the laboratory and has blocked the formation of harmful pathogens on ventilator tubes in animal models. Marin H. Kollef, M.D., of the Washington University School of Medicine, and colleagues in the NASCENT Investigation Group report on a randomized controlled trial involving patients at 54 centers expected to require mechanical ventilation for 24 hours or longer. Between 2002 and 2006, 2,003 patients were randomly assigned to undergo intubation with either a silver-coated tube or a similar tube that was not coated.

Of 1,509 patients who were intubated for 24 hours or longer, 4.8 percent of those with silver-coated tubes developed ventilator-associated pneumonia, compared with 7.5 percent of those with uncoated tubes—a 35.9 percent relative reduction in risk. Among 1,932 patients who were on ventilators for any length of time, the silver coating was associated with a 34.2 percent relative reduction in risk of developing pneumonia (3.8 percent of those with silver-coated tubes vs 5.8 percent with uncoated tubes).

In addition, the silver-coated tubes were associated with a delayed occurrence of ventilator-associated pneumonia. No differences were seen between the two groups in median (midpoint) duration of intubation, length of stay in the intensive care unit (ICU) or in the hospital, death rates or frequency and severity of adverse events.

"In conclusion, the results of this large, randomized, multicenter study demonstrated that the silver-coated endotracheal tube significantly reduced the incidence of microbiologically confirmed ventilator-associated pneumonia and had its greatest benefit during the peak time of ventilator-associated pneumonia occurrence, without any notable adverse events," the authors conclude. "The silver-coated endotracheal tube appears to offer a unique approach because it is the first intervention that becomes user-dependent after intubation, requiring no further action by the clinician."

This study, including design, data collection, statistical analysis and manuscript preparation, was supported by a research grant from C. R. Bard Inc. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Editorial: Silver-Coated Endotracheal Tubes Not Definitive Solution But Could Benefit High-Risk Patients

"Based on the results of this trial, should clinicians reconsider guidelines for ventilator-associated pneumonia prevention and use a silver-coated endotracheal tube in all patients requiring intubation and mechanical ventilation in the ICU?" writes Jean Chastre, M.D., of the Groupe Hospitalier Pitie-Salpetriere, Paris, in an accompanying editorial.

"The answer is probably yes for the subset of patients at very high risk of developing early-onset ventilator-associated pneumonia, such as neurologically impaired patients or trauma patients, because the greatest effect of the intervention appeared to occur during the first 10 days of mechanical ventilation and was clinically relevant, with minimal effect on clinician workload," Dr. Chastre writes.

"Important uncertainties exist regarding the exact benefit of silver-coated endotracheal tubes," Dr. Chastre concludes. "Consequently, silver-coated tubes should not be viewed as the definitive answer for ventilator-associated pneumonia prevention, and, until additional data confirm the clinical effectiveness and cost benefit of these devices, their issue should be restricted to high-risk patients treated in ICUs with benchmark value-based infection rates that remain above institutional goals despite implementation of a comprehensive strategy of usual preventive measures to prevent ventilator-associated pneumonia."

Dr. Chastre reported receiving consulting and lecture fees from Pfizer, Brahms, Wyeth, Johnson & Johnson, Bayer-Nektar and Arpida. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Saturday, July 3, 2010

Medication-free home ventilation system designed to remove allergens


The EZ Breathe system improves indoor air quality and eliminates conditions for allergens to grow. The system ventilates by drawing moist, stale, contaminated air out of the home, replenishes by replacing moist air with fresh dry air and regulates airflow to reach and maintain a desired level of humidity. A complete home air exchange occurs about six to 10 times each day. Filter- and cartridge-free, EZ Breathe does not require additional cost to maintain and covers up to 7000 square feet, operating at a mere $2-$4 per month!

Studies have indicated that home intervention, in the form of a ventilation system, is an effective, preventative approach to asthma and allergy symptoms, and is more cost effective than waiting for symptoms to arrive and then treating them accordingly.


 
While pollen is a vital element for the fertilization of plants, its allergic effects wreak havoc on at least 20 percent of the nation's population, with 5 percent suffering so badly, they require the aid of a specialist, said Richard Lockey, director of the Division of Allergy and Immunology at the University of South Florida, a state reporting record pollen counts, due to oak and cypress tree populations.

Oral antihistamines are the most commonly prescribed allergy medication to address the adverse affects of pollen. However, these remedies can cause drowsiness. Moreover, drug manufacturers warn their patients to avoid activities that require alertness such as driving, operating machinery and performing physically dangerous tasks when taking antihistamines.



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