The Ervin Test Machine measures both the Durability (life) and Transmitted Energy (impact) of the abrasive, which are the two most important measures of value and quality.
The Ervin Test Machine is the only device designated by specifications for the evaluation of metal abrasives.
the Ervin Test Machine was engineered and developed to provide a method to evaluate the quality of metal abrasives. This information can assist the abrasive user in making the best abrasive ｓelection to insure efficiency and the lowest possible cost in production use.
The Ervin Test Machine will measure both the Durability (life) and Transmitted Energy (impact energy) of the abrasive, which are the two key measures of the value and quality of a metal abrasive.
The Ervin Test Machine is portable and easy to use.
The Ervin Test Machine has become the standard measuring tool in the industry. It is used by most of the abrasive manufacturers in the world to assess the quality and consistency of the abrasive manufacturing processes. Also, many large, metallic abrasive users have purchased Ervin Test Machines for their quality assurance laboratories to insure that the quality of the abrasive is consistent and as specified when purchased.
Over 200 Ervin Test Machines have been sold and are in use all over the world. Widespread acceptance of the Ervin Test Machine centers around the fact that it gives consistent and reliable results in a relatively short time.
TESTING SHOT AND GRIT
the Ervin Test Machine for abrasives was designed to simulate the action of a production blast cleaning and/or shot peening machine, and provide a laboratory tool to quickly test the performance of metal abrasives.
During testing, the abrasive is propelled by a centrifugal wheel or beater head rotating at approximately 7,000 RPM which accelerates the abrasive to a velocity of approximately 200 feet per second, comparable to the velocity of a production blast cleaning or shot peening machine. The abrasive is thrown against an anvil surface. After impact, the abrasive falls to the bottom of the rotating anvil recycling assembly which picks up the abrasive and returns it to the wheel ｗhere it is thrown against the anvil surface again. The anvil recycling assembly rotates at 25 RPM which means that the abrasive is recycled through the wheel 25 times per minute. The Durability Test described below establishes the conditions for measuring the durability or fatigue life of the abrasive.
During Durability testing, the peening attachment is replaced by a plug that continues the curved surface of the anvil. For testing of Transmitted Energy, the plug is replaced with the peening attachment which holds an Almen Strip in the path of the abrasive being tested.
Ervin Test Machine Calibration
The Ervin Test Machine is offered in either 110 volt 60 Hertz, 220 volt 60 Hert乙 100 volt 50 Hertz or 200 volt 50 Hertz, depending on the customer's requirements. All Ervin Test machines are calibrated at the factory using 110 volt AC 60 Hertz and converted to the power requirements of the customer. The Ervin Test Machine should be recalibrated after every 20 durability tests or after any mechanical changes (such as new V-belts) to maintain reliable test results.
An S-550 calibration shot, developed in the Ervin laboratory, is supplied with the machine. Additional supplies are available from Ervin as needed.
Calibration Procedure
Check for worn or slipping drive belts. Replace if necessary.
Make sure the set screws in the adjustable sheaves are tight.
Check the condition of the screen using a flashlight. Replace the screen if it has any holes worn through.
NOTE: Keep a dust bag tied over the tubular opening of the Anvil recycling assembly to capture any dust created when running the test.
4.Start the Ervin Test Machine and check the rotation speed of the anvil/recycling device by timing 10 revolutions with a stop watch and calculate the RPM. The rotation speed of the anvil recycling device must be 25 RPM ± 0.5 RPM.
5.Adjust the speed of the anvil/recycling device by changing the setting of the adjustable sheave on the low speed drive motor and retest speed.
6.Repeat steps 4 and 5 until the speed is correct.
7.Check the RPM of the High Speed Beater Shaft with a tachometer.
NOTE: Each Ervin Test Machine is an individual and may have different requirements for the beater shaft speed. The proper speed is determined using the S- 550 Calibration Shot.
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