Vacuum Box Testing

Vacuum Box Testing is a test method that is used to detect leaks. It is a practical way of testing in comparison to the quantitative measures used to examine objects. Vacuum Box Testing can be used to test objects on which a pressure differential can be created across the area to be examined. The common application areas of Vacuum Box Testing include piping systems, pressure vessels, and storage tanks.

There are various types of boxes or frames used in Vacuum Box Testing depending upon the application area. Vacuum box inspection of lap welds, butt welds and fillet welds. These vacuum boxes are used to examine a small and specific portion of the welded area to produce accurate results. The vacuum boxes used in vacuum box testing are fabricated of thick, clear Perspex with a closed cell foam seal along the bottom edge.

Before proceeding with the vacuum box testing, a vacuum gauge and hose coupling are fitted in the box. Then a soapy solution is put on the line of welding in the testing object. After that the vacuum box is placed over the testing object and a vacuity is created inside the box. Now, the object is observed, if there any drop in the vacuum or bubble formation on the surface then it shows that there is leak in the weld and the object is defected or faulty.

Vacuum Box Testing is a very popular non-destructive testing method that is widely used to test various objects against defects, flaws, leaks, or other imperfections. It is very efficient and effective way of testing various welded objects for any kind of leaks or defects. There are basically two main types of Vacuum Box systems used for performing vacuum testing (a) High Pressure Models that are mainly used for inspection of above ground storage tanks that have been in service. (b) Low Pressure Models used for weld integrity checks on new tank builds where gross defects are the main concern.

Abcndt.com use Vacuum box testing in non-destructive and destructive testing methods to increase customer satisfaction and lower manufacturing costs. They cater to industries, such as automotive, aviation, construction, power plants, manufacturing, railways, military, and naval industry. ABC Testing Inc. have Certified Welding Inspectors (CWI) doing welding inspections for steel, aluminum, specialized metals like Inconel, Monel and NiAlBrz, and many other alloys. The company uses approved procedures to specific industry standard. Browse through www.abcndt.com for more information.

Adavantages of GPR

Advantages of GPR(Ground Penetrating Radar) :-

GPR is Cost effective technique.
GPR is Hi resolution, vertically and laterally.
GPR is used in Numerous areas of application.

Is Doing An X Ray Safe

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film or digital media. Standard x-rays are performed for many reasons, including diagnosing tumors or bone injuries.

X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially-treated plates (similar to camera film) or digital media and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film).

When the body undergoes x-rays, different parts of the body allow varying amounts of the x-ray beams to pass through. The soft tissues in the body (such as blood, skin, fat, and muscle) allow most of the x-ray to pass through and appear dark gray on the film or digital media. A bone or a tumor, which is more dense than the soft tissues, allows few of the x-rays to pass through and appears white on the x-ray. At a break in a bone, the x-ray beam passes through the broken area and appears as a dark line in the white bone.

X-ray technology is used in other types of diagnostic procedures, such as arteriograms, computed tomography (CT) scans, and fluoroscopy.

When medical X-rays are being produced, a thin metallic sheet is placed between the emitter and the target, effectively filtering out the lower energy (soft) X-rays. This is often placed close to the window of the X-ray tube. The resultant X-ray is said to be hard. Soft X-rays overlap the range of extreme ultraviolet. The frequency of hard X-rays is higher than that of soft X-rays, and the wavelength is shorter.

Hard X-rays overlap the range of "long"-wavelength (lower energy) gamma rays, however the distinction between the two terms depends on the source of the radiation, not its wavelength; X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei.

Since antigen's discovery that X-rays can identify bony structures, X-rays have been developed for their use in medical imaging. Radiology is a specialized field of medicine. Radiographers employ radiography and other techniques for diagnostic imaging. Indeed, this is probably the most common use of X-ray technology.

X-rays are especially useful in the detection of pathology of the skeletal system, but are also useful for detecting some disease processes in soft tissue. Some notable examples are the very common chest X-ray, which can be used to identify lung diseases such as pneumonia, lung cancer or pulmonary edema, and the abdominal X-ray, which can detect ileus (blockage of the intestine), free air (from visceral perforations) and free fluid (in ascites).

In some cases, the use of X-rays is debatable, such as gallstones (which are rarely radiopaque) or kidney stones (which are often visible, but not always). Also, traditional plain X-rays pose very little use in the imaging of soft tissues such as the brain or muscle. Imaging alternatives for soft tissues are computed axial tomography (CAT or CT scanning), magnetic resonance imaging (MRI) or ultrasound. Since 2005, X-rays are listed as a carcinogen by the U.S. government.

Diagnostic x-rays are safe. But who hasnt wondered about them when undergoing a chest x-ray, mammogram, routine dental x-rays, or an x-ray for a broken bone?

The safety of routine X-rays has been called into question following the unexpected discovery that cells exposed to low doses avoid or delay repairing damaged DNA.

Puzzlingly, cells given higher doses of X-rays were faster and more efficient at patching up any damage. But the German researchers who made the discovery say it is not clear whether the sloppy repairs that follow low level exposure is a good or bad thing.

Kai Rothkamm and Markus Brich, at the University of Saarland in Homburg, acknowledge that unrepaired breaks in DNA could well lead to cells becoming cancerous. But it is equally possible, they say, that the failure to repair low-level DNA damage has evolved as a safety measure.

Other experts state that no scientific data indicate any danger. In fact, there is evidence that low doses may actually reduce the chance of cancer. The question about the amount of radiation you receive is difficult for x-ray technicians and doctors to answer because very few x-ray units have an instrument to measure the radiation to the patient.

You may have heard that even the smallest amount of radiation may cause cancer. Based on this unscientific assumption, the risk of causing a fatal cancer from a chest x-ray is 10 times greater than the risk of dying in a commercial airline flight. Or a CT scan of the kidneys has a greater risk of inducing a fatal cancer than a cigarette smoker has of dying from any cancer. These statements produce unnecessary worry. There is no data to show any risk from diagnostic x-rays.

Lastly, radiation during pregnancy may lead to birth defects. Always tell your radiologist or physician if you suspect you may be pregnant.

About the Author

Jigfo.com is a global platform for sharing and learning knowledge. For more information on this article topics visit:

http://www.jigfo.com

http://x-linked-agammaglobulinemia.jigfo.com/

http://x-rays-of-the-orbit.jigfo.com/

http://abuse.jigfo.com/

http://centralcoastrays.jigfo.com/

Article Source: Content for Reprint

Salt Spray Weathering

Salt spray testing under ASTM B117 conditions subjects the test samples to conditions that are actually more corrosive than usual “real world” exposure. This is because the test uses sodium chloride in de-ionized water and usually lacks the moderating effects of other dissolved salts such as those containing calcium and magnesium, which tend to be somewhat protective.

is the most popular form of testing for protective coatings. These tests have been used for more than 90 years as accelerated tests in order to determine the degree of protection afforded by both inorganic and organic coatings on a metallic substrate. The most widely used salt spray (fog) tests are described below.

The neutral salt spray (fog) test (ASTM B 117): is perhaps the most commonly used salt spray test in existence for testing inorganic and organic coatings, in particular where such tests are used for material or product specifications. The duration of the test can range from 8 to over 3000 hours, depending on the product. A 5% sodium chloride solution containing not more than 200 parts per million (ppm) total solids and with a pH range of 6.5 to 7.2 is used. The temperature of the salt spray chamber is controlled to maintain 35 + 1.1 or – 1.7Þ C (95 + 2 or -3Þ F) within the exposure zone of the closed chamber.

The acetic acid salt spray (fog) test (ASTM G 85, Annex A1): is also used for testing inorganic and organic coatings, but is particularly applicable to the study or testing of decorative chromium plating and cadmium plating on steel or zinc die castings, as well as for the evaluation of product quality. This test can be as short as 16 hours, although it normally ranges from 144 to 250 hours or more. Similar to the neutral salt spray test, a 5% sodium chloride solution is used, but the solution is adjusted to a pH range of 3.1 to 3.3 by the addition of acetic acid. The temperature of the salt spray chamber is controlled to the same temperature range as for neutral salt spray.

The copper accelerated acetic acid salt spray (fog), or CASS test (ASTM B 368): is primarily used for the rapid testing of chromium plating on steel and zinc die castings. It is also useful in the testing of anodized, chromated, or phosphated aluminum. The duration of this test ranges from 6 to 720 hours. A 5% sodium chloride solution is used, with one gram of copper (II) chloride dihydrate added to each 3.8 liters of salt solution. The solution is then adjusted to a pH range of 3.1 to 3.3 by adding acetic acid. The temperature of the salt spray chamber is controlled to the same temperature range as for neutral salt spray and for acetic acid salt spray.

Leak Testing

Leak testing equipment is used to measure the escape of liquids, vacuum or gases from sealed components or systems. Some configurations require a separate leak detector or sensor as an input. Such types of leak testing equipment are often equipped with various other components such as pumps, calibrators, gauges and cases. Output options include analog voltage, analog current, frequency or modulated frequency, and switch or alarm signal. Some leak testing equipment includes an analog front panel with potentiometers, dials, and switches. Other features a digital front panel that is set up with a keypad or menus. Leak testing equipment with a serial interface, a parallel interface, and/or integral application software is also available.

Leak test method is an important specification to consider when choosing leak testing equipment. Methods include bubble testing, colorimetric development, electronic gas detection, mass flow, mass spectrometry, and hydrogen leak detection. Bubble testing is used for applications which do not require high sensitivity. A pressurized test object is submerged in a water tank so that the emergence of bubbles indicates a leak. Colorimetric development uses a chemical developer which reacts with the leaking fluid, causing a visible color change to occur at the place of leakage. Leak testing equipment that uses electronic gas detection pressurizes the test object with a tracer gas so that a sniffer probe can be used to find the leak. Mass flow devices direct the leakage across a heating element. The temperature change produces an output voltage proportional to mass flow. Mass spectrometers are used with helium leak detection. Leak testing equipment that is designed to detect hydrogen leaks is also available.

Leak testing equipment may use test methods such as pressure differential (decay) and ultrasonic leak detection. A pressure decay test involves the initial inflation of the test object and the establishment of a reference pressure. After a designated amount of time, the pressure is measured again and the initial and final measurements are compared. The change in pressure can be used to calculate the leak rate given the internal volume of the device. Ultrasonic leak detection (sonic flow, choked flow) involves the turbulent flow of a fluid across a pressure boundary to create acoustic waves. These waves are transmitted through the medium of the fluid itself, through the containment structure, or through the air surrounding the containment structure. Leak testing equipment that uses other test methods is also available.