5-16 Bar Stroke Brake Chamber Tester

TESTS

1. DETERMINING CHARACTERISTIC VALUES AND MAKING A FORCE/PRESSURE CURVE

When the stroke is at zero, the movable table of the tester is touched to the end of the cylinder with a tare force close to zero. Hydraulic fluid begins to be pumped into the cylinder. The pressure at the moment the value changes in the load cell connected to the test device swivel table is recorded and the maximum pressure that creates zero force in the minimum stroke is found.

The stroke is maximized. The same process is repeated and there is the maximum pressure creating zero force at maximum stroke.

The maximum allowable pressure is recorded as the minimum pressure that creates the maximum force. This pressure is then applied for minimum and maximum strokes while in contact with the turntable. The pressure is relieved until the force reading starts to decrease. The last pressure value, which gives the same force as the maximum pressure, is recorded.

At the minimum and maximum strokes, the pressure is gradually increased in the defined pressure range and the forces applied to the test device table, which is contacted with tare force, are measured for each pressure. A linear curve fit is made to the obtained values ​​and the slope is calculated. Then, the generated direct deviations of the individual measuring points are calculated and the maximum deviation is found.

2. REPEATABLE PERFORMANCE TEST AT MAXIMUM AND OPERATIONAL PRESSURE 

In Maximum and Minimum strokes, similar to the tests above, force measurements are made while the test device table is in contact with the maximum allowable pressure and the operational pressures declared by the manufacturer (approximately 2/3 max. pressure).

The above-described measurement is repeated 25 times for each pressure and each stroke condition (2 combinations, a total of 4 conditions).

The maximum, minimum and force values ​​obtained and the average of 25 measurements are recorded.

DETERMINING CHARACTERISTIC VALUES AND EXTRACTING CURVES

When the bellows is empty, the tester table is brought to the contact position with a force close to zero.

The bellows starts to pressurize gradually within the defined pressure range.

For each pressure value, the force applied to the tester table is first recorded. Thus, the pressure force relationship is found.

After the force is registered, the tester table is slowly moved in the direction where the bellows will open. The pressure is kept constant during the movement. At some point the bellows completes its movement and leaves the table. This point is understood when the force on the table reaches a value close to zero. This point is also recorded as the stroke value of the relevant pressure and the stroke pressure relationship is found.

Curve fit is done by using the least square method with the values ​​found. The 15mm stroke value is calculated and confirmed here.

SPRING SAFETY BRAKE TESTS

The pressure in the bellows is reset to activate the spring-loaded emergency brake. The moving end of the bellows is connected to the test device table and the stroke is started by moving the table. The stroke/force value is recorded at certain intervals and this relationship is defined.

Another value defined for the emergency brake is “Release Pressure”. In order to find this value, the tester table is brought into contact with the bellows. Pressure is then applied. As the force value reads increases, the table is retracted and a stroke value of up to 10mm is achieved. The pressure that gives this 10 mm stroke value is recorded as the release pressure.