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autoclave

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    الصورة الرمزية جوهرة المحيط
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    autoclave


    autoclave
    An autoclave is a pressurized device designed to heat aqueous solutions above their boiling point to achieve sterilization. It was invented by Charles Chamberland in 1879.[1] The term autoclave is also used to describe an industrial machine in which elevated temperature and pressure are used in processing materials.





    Introduction
    Under ordinary circumstances (at standard pressure), liquid water cannot be heated above 100 °C in an open vessel. Further heating results in boiling, but does not raise the temperature of the liquid water. However, when water is heated in a sealed vessel such as an autoclave, it is possible to heat liquid water to a much higher temperature. As the container is heated the pressure rises due to the constant volume of the container (see the ideal gas law). The boiling point of the water is raised because the amount of energy needed to form steam against the higher pressure is increased. This works well on solid objects; when autoclaving hollow objects, however, (hypodermic needles, tools, etc.), it is important to ensure that all of the trapped air inside the hollow compartments is removed. Autoclaves may achieve air removal by downward displacement, super atmospheric, transatmospheric or sub-atmospheric pulses.
    Autoclaves are widely used in microbiology, medicine, veterinary science, dentistry, podiatry and metallurgy. The large carbon-fiber composite parts for the Boeing 787, such as wing and fuselage parts, are cured in large autoclaves.[2]


    Autoclaves in medicine

    Stovetop autoclaves need to be monitored carefully and are the simplest of all autoclaves
    A medical autoclave is a device that uses steam to sterilize equipment and other objects. This means that all bacteria, viruses, fungi, and spores are inactivated. However, in 2003 scientists discovered a single-celled organism, Strain 121, that survives traditional autoclave temperatures.[2] Prions, like those associated with Creutzfeldt-Jakob disease, also may not be destroyed by autoclaving at the typical 121 degrees Celsius for 15 minutes or 134 degrees Celsius for 3 minutes, but can be destroyed with a longer sterilisation cycle of 134 degrees Celsius for 18 minutes[citation needed].
    Autoclaves are found in many medical settings and other places that need to ensure sterility of an object. They were once more common, but many procedures today use single-use items rather than sterilized, reusable items. This first happened with hypodermic needles, but today many surgical instruments (such as forceps, needle holders, and scalpel handles) are commonly single-use items rather than reusable. See waste autoclave.
    Because damp heat is used, heat-labile products (such as some plastics) cannot be sterilised this way or they will melt. Some paper or other products that may be damaged by the steam must also be sterilized another way. In all autoclaves, items should always be separated to allow the steam to penetrate the load evenly.
    Autoclaving is often used to sterilize medical waste prior to disposal in the standard municipal solid waste stream. This application has grown as an alternative to incineration due to environmental and health concerns raised by combustion byproducts from incinerators, especially from the small units which were commonly operated at individual hospitals. Incineration or a similar thermal oxidation process is still generally mandated for pathological waste and other very toxic and/or infectious medical wastes.




    Autoclave quality assurance

    Multiple large autoclaves are used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal.

    Sterilization bags often have a “sterilization indicator mark” that typically darkens when sterilization temperatures have been reached. Comparing the mark on an unprocessed bag to a bag that has been properly cycled will show an obvious visual difference.
    There are physical, chemical, and biological indicators that can be used to ensure an autoclave reaches the correct temperature for the correct amount of time.
    Chemical indicators can be found on medical packaging and autoclave tape, and these change color once the correct conditions have been met. This color change indicates that the object inside the package, or under the tape, has been autoclaved sufficiently. Biological indicators include attest devices. These contain spores of a heat-resistant bacterium, Geobacillus stearothermophilus. If the autoclave does not reach the right temperature, the spores will germinate, and their metabolism will change the color of a pH-sensitive chemical. Physical indicators often consist of an alloy designed to melt only after being subjected to 121°C or 249°F for 15 minutes. If the alloy melts, the change will be visible.
    In addition to these indicators, autoclaves have timers, temperature and pressure gauges that can be viewed from the outside.
    There are certain plastics that can withstand repeated temperature cycling greater than the 121°C or 249°F required for the autoclaving process. PFA is an example.
    Some computer-controlled autoclaves use an F0 (F-naught) value to control the sterilization cycle. F0 values are set as the number of minutes of equivalent sterilization at 121°C or 249°F (e.g: F0 = 15 min.). Since exact temperature control is difficult, the temperature is monitored, and the sterilization time adjusted accordingly.


    Types of autoclaves:

    Front loading (cylindrical chamber or rectangular chamber from 40 litre to 700 litre)
    Top loading (cylindrical chamber from 60 litre to 200 litre)
    Pass through or double-ended (so that load enters in one room and is taken out when autoclaved via other door in an adjoining room). Cylindrical chambers of 150 or 200 litre and rectangular chambers of 350, 450 or 700 litre)
    Most sizes of laboratory autoclaves can be supplied as either electric heating (heats water in the autoclave to produce the steam) or steam heating (live steam introduced from external source)



  2. [2]
    جوهرة المحيط
    جوهرة المحيط غير متواجد حالياً
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    الصورة الرمزية جوهرة المحيط


    تاريخ التسجيل: Sep 2006
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    Laboratory Autoclaves
    For the benchtop autoclaving of a few instruments or small amount of media, etc. then there is a range of Prestige portable laboratory autoclaves listed on our website with different sizes and cycle choices. The following guide is aimed at customers with more substantial or varied requirements for their autoclaves.

    Progen Scientific distribute Priorclave autoclaves which come in sizes from 40 litre laboratory benchtop to 700 litre capacity. The main considerations for the choice of autoclave are the size of loads to be autoclaved, the type of loads, number of loads per day, services requirements (electric, water, drains, etc.) and the autoclave's location.
    Please view our laboratory autoclaves products page to find the exact autoclave you need. You can also phone or enquire and talk to a customer service representative.

    Listed below is a range of information, answers and questions you should consider when choosing a laboratory autoclave:
    Types of autoclaves:

    Front loading (cylindrical chamber or rectangular chamber from 40 litre to 700 litre)
    Top loading (cylindrical chamber from 60 litre to 200 litre)
    Pass through or double-ended (so that load enters in one room and is taken out when autoclaved via other door in an adjoining room). Cylindrical chambers of 150 or 200 litre and rectangular chambers of 350, 450 or 700 litre)
    Most sizes of laboratory autoclaves can be supplied as either electric heating (heats water in the autoclave to produce the steam) or steam heating (live steam introduced from external source)
    Types of autoclave loads

    Glassware, instruments & apparatus
    Standard use of autoclave with option of vacuum drying which allows loads to be removed 'dry' with out operator intervention
    Media preparation
    The following options are recommended for effective media preparation with reduced cycle times: freesteaming (improved temperature distribution); accelerated cooling (extra loads per day); media warming (when cycle finishes media is kept at 40oC, handy for overnight cycles); performance testing
    Fluid and diluent sterilisation
    Priorclave recommends the following options for effective fluid sterilisation: load sensed process timing (guaranteed sterilising times as cycle does not start until probe placed in centre of load reaches cycle temperature); accelerated cooling (extra loads per day)
    Waste
    The greatest difficulty with some waste loads is achieving adequate load steam penetration especially where there are large volumes of air (petri dishes, porous loads, etc.) and/or large quantities of insulating plastic materials. The following options are recommended: freesteaming (improved temperature distribution); pulsed freesteaming (improved steam penetration); accelerated cooling (more loads per day); pre-cycle vacuum (excellent air removal in conjunction with pulsed freesteaming); vacuum cooling cycle (even faster cycles); performance testing
    Porous loads (e.g. textiles)
    The key requirements are good steam penetration and effective drying. The following options are strongly recommended: pulsed freesteaming (improved steam penetration) in conjunction with pre-cycle vacuum for effective air removal; vacuum drying (essential for load to be removed 'dry' at the end of the cycle)

    Health Care
    Priorclave are well acquainted with the U.K. Health Service HTM2010 requirements and offer a compliance package suitable for all their laboratory autoclaves. Their technical department are well experienced in performance testing to HTM2010 requirements. Priorclave's calibration and performance testing procedures are fully accredited by UKAS.
    The HTM2010 compliance package includes the following: self-monitoring (TACTROL® control system continuously monitors itself for correct calibration; mechanical cycle counter; setting lock; independent thermal lock; pressure gauge test port. Priorclave also recommend fitting a process printer for clear, automated record keeping and a multi-programme memory where more than one type of cycle is used.
    Custom applications
    Double door autoclaves are recommended where a clean room or containment laboratory (category 3, etc.) is being installed. Where there is concern about bio-hazardous material in the autoclave exhaust, a microbiological filter can be fitted. Unfiltered condensate is returned to the autoclave for sterilisation
    Non-sterilisation applications
    Many other systems use hot water or steam and Priorclave autoclaves have been adapted for the following applications: food processing (simultaneously cooking and shrink wrapping vegetables); plastics (re-hydration of moulded nylon components; accelerated curing; construction (testing conditions for curing roof tiles)
    Autoclave location

    Before choosing your laboratory autoclave you need to check that it will fit in the location and can be delivered to that location. There should also be approximately 1 metre access at the sides and rear (minimum 500mm.) for service access and 2 metres at front of front loaders. Electrical supply (single or triple phase as required), steam supply (if required) and drain / venting should also be considered before choosing the autoclave.
    If the autoclave is on hospital premises then it must comply with HTM2010 regulations (see above)
    Services Required (general, may vary with autoclave and application)
    Electrical Supply: 380/415 volts, 50 Hz, three phase rated at 15 amps per phase with earth and neutral or 240 volts, 50Hz, single phase rated at 30 amps with earth and neutral terminated at a suitably fused switched socket RS Components Stock Number 367 4086 within 2 metres run of the rear of the Priorclave.
    Steam supply (if required): Discuss with Progen representative or we can arrange site visit with a Priorclave representative
    Water Supply: Not required, manual fill. If the Auto Water Filling option is supplied then a 15mm cold water supply terminated at a stopcock within 2 metres run of the rear of the Priorclave should be supplied.
    Drain Service: A 35mm sealed drain with an untrapped 22mm entry, capable of withstanding steam at 136 ° C, with a constant fall to waste, vented at a high level outside of the building to satisfy the requirements of BS 2646 Part 2 1990. A separately trapped, 22mm drain should be provided for the Auto Water Fill tank. All drains should be provided at a low level within 2 metres run of the rear of the Priorclave
    other considerations
    Number of loads per day
    Manual load settings or pre-programmed
    Installation and commissioning
    Performance testing
    Extended warranty / Service contracts
    Options and accessories
    • Vertical power doors are an option on front loading rectangular section autoclaves from 230 to 700 litre sizes
    • Load-lite lifting hoist - helps out with heavy loads from top loading autoclaves
    • Loading trolleys - to help roll loads in and out of front loading laboratory autoclaves
    • Automatic waterfill - fills the autoclave between cycles (usually R.O. water)
    • Air intake filter - filters air taken into the autoclave (standard with vacuum drying or cooling cycles)
    • Serial interface - for monitoring by computer
    • Self-monitoring - TACTROL® continuously monitors itself for correct calibration
    • Recorders - for independent monitoring. Load and pressure sensing channels available
    • Waste containers - for operator safety and protection of your autoclave with waste loads. These contain spillages whilst allowing good steam penetration
    • Load baskets - check the maximum number of load baskets for your size of autoclave
    The choice of an autoclave, such as those in the Priorclave range, can represent a big investment financially and you want to make sure it performs to all your expectations and sterilises your loads safely and correctly. Progen Scientific strongly recommends a visit by one of their representatives to your site and, where necessary, a site visit by a Priorclave representative can be arranged

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  3. [3]
    جوهرة المحيط
    جوهرة المحيط غير متواجد حالياً
    عضو شرف
    الصورة الرمزية جوهرة المحيط


    تاريخ التسجيل: Sep 2006
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    وسام الشكر

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    المواضيع السابقة باللغة الانكليزية لانه باعتقادي ان شرحها بالانكليزي افضل للكل مهندس.

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  4. [4]
    شكرى محمد نورى
    شكرى محمد نورى غير متواجد حالياً
    مشرف


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    احسنت واعانكِ الله على المجهود الذي بذلتهِ في التقرير .

    شكرا لكِ ودمتي ذخرا لنا .

    البغدادي

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  5. [5]
    جوهرة المحيط
    جوهرة المحيط غير متواجد حالياً
    عضو شرف
    الصورة الرمزية جوهرة المحيط


    تاريخ التسجيل: Sep 2006
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    وسام الشكر

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    هناك سؤال مهم جدا
    ماهو فرق استعمال ال Autoclave عن استعمال oven ؟
    والجواب هو
    ان ال Autoclave يستخدم للتعقيم باستخدام الحرارة و الضغط
    وال oven يستخدم للتعقيم باستخدام الحرارة فقط
    ففي بعض المواد عند طبيب الاسنان و في بعض الادوات لا يمكن تعقيمها بحرارة ال oven ولكن يستخدم ال Autoclave

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  6. [6]
    المهندسة البغدادية
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    شكرا جزيلا
    هذا الموضوع مفيد و قيم

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  7. [7]
    bu3mmar
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    تسلمين اختي على الموضوع القيم

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  8. [8]
    bu3mmar
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    Because damp heat is used, heat-labile products (such as some plastics) cannot be sterilised this way or they will melt. Some paper or other products that may be damaged by the steam must also be sterilized another way. In all autoclaves, items should always be separated to allow the steam to penetrate the load evenly
    و هذا اهم فرق بين الاتوكلاو و الـoven

    دمتي بود

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  9. [9]
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    مشاركة شيقة جدا ويا ريت كان في شوية صور.

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  10. [10]
    م/احمد زاكر
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    الصورة الرمزية م/احمد زاكر


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    مشكووووووووووووووور

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