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Float ball type dead weight tester

time£º2018-10-15 16:34    source£ºshelok pressure transmitter

 Float ball type dead weight tester




Floating ball type pressure meter with compressed air or nitrogen gas as the pressure source, is aAerodynamic load pressure meter that wth precision float ball in pressure area of lower sphere working state for the effective area of the floating ball. As picture (1) shows,  precision float ball in a cylindrical nozzle, special weight effects at the top of the ball and the pressure in the nozzle effects at the bottom of the ball, so that the ball floating in the nozzle.  When the special weights gravity is balanced to the pressure force, the floating ball pressure meter can output a stable and precise pressure value.






             (1) Floating Ball Pressure Meter Principle








Compressed air or nitrogen gas through the flow regulator into the bottom of the ball, and through the gaps between the balls and the nozzle put into the atmosphere. At the bottom of the ball generate pressure will held up the ball. When vent gas flow rate is equal to the flow from the regulator, the system is in equilibrium. At this time, the ball will float a certain height, the pressure area at the bottom of the ball (which is the effective area of the float) is certain. Due to a pressure at the bottom of the sphere through pressure stabilizer as the output pressure, so the output pressure will be proportional to the weight load.  


When add or reduce the weights on the weight frame, will change the balance measurement system, resulting in the float falling or rising, the flow of atmosphere immediately changed, the pressure at bottom of ball is also changed, the flow regulator will change gas inflow in timely, make the system reach equilibrium again and keeping the effective area of the float is constant, keeping output pressure is proportional to the weight load. Ensure high accuracy of float pressure meter.








1. Float ball pressure meter is built-in automatic flow regulator, after any increase or decrease in weight without further operation, then can output precise pressure.


2. The floating ball does not drop when working, can continuously and stably accurate output pressure signal.


3. Floating ball pressure meter with self-adjusting function.


4. When the instrument is working, the gas flow make the ball suspend in nozzle, the ball is non-contact with the nozzle. Friction is small, reproducible, high resolution, and eliminates the need for rotating weight. 5. In working process, the airflow can constantly clean the float ball, to ensure high reliability of the instrument.


(2) The output appearance when remove the cover


Installation and Use:


Use Introduction:


In accordance with the requirements of the user manual, put the float ball pressure meter at a flat place and connected properly, connect by the detecting instrument, clean the floating ball with silk, and then add the floating ball and weight frame and weights on the pressure meter.


Start using the float gauge. If find the floating ball can not float up, please follow the progressive approach of exclusion: First, make sure the gas supply pressure is not fixed value; Second, pressure joint and output joint must not be reversed; Third, the pipe connection must be seal between pressure source, pressure source joint, pressure output joint and the detecting instrument.  


Check mode: Close the outlet valve and see whether the float can float up, if the float can float up, that there is a leak between the output and the measured instruments, if the float can not float up, there is a leak between gas source and gas source joint.


1 Placement



The pressure meter should be place that the temperature nearly 20¡æ, humidity is 10-75%. The atmosphere without corrosive medium and vibration source. When place it on the worktable, remove the cover, and adjust it by adjustable screw on the bottom of the meter.When the spirit level bubble in middle position, the pressure meter is in a correct working position.


2. Pipeline connection


Use the two plastic pipes connect with pressure source and detecting instrument, then put the plastic pipe plug into the jack on the side of the chassis. Note, the pressure source plug should put into pressure source jack, another plug should put into output jack. After put plug into jack, screw inward the nuts to prevent plug remove and leak.


The pressure source should be clean and dry and oilless compressed air or nitrogen gas, when the compressed air can not reach the purification requirements, must use bottled ordinary nitrogen. Air pressure as long as no more than the instrument highest and lowest pressure values, pressure meter can keep precision. But, the pressure meter is calibrated in the fixed pressure source, so the pressure source should close to the fixed pressure source value.


3. Operation


First, adjust pressure source pressure when use, then open pressure source valve and output valve, and put the weight frame on the ball. When the ball floating up, the pressure meter will output a pressure valve of weight frame(0.001mpa or 0.005mpa).


Gradually add weights according to the calibrated instruments requirements required pressure value of weight, when the ball floating up again, the pressure meter can output the needed calibrate pressure.


Notice when operation:


(1) when add or reduce weights, it should not change to much in one time;


(2) Don’t revolve the weights when put it on the frame, or else will influence the accuracy of the output value.


(3) The weights must be removed after calibration, turn off the pressure source valve, then put off the calibrated instrument. The instrument can not be put off when add pressure to avoid impacting the floating ball.


(4) Pressure meter’s output pressure value is the sum of adding weight and the mark pressure value on the weight frame. The error of output pressure value will not more than ±0.05%. When the output pressure value less than 10% of the pressure meter’s upper limit value, the error is not more than ±0.05% of 10% of upper limit value.


4. Clean


Before use, should check the floating ball and nozzle, or else will influence the output accuracy. The ball and nozzle should be cleaned by ethyl alcohol, and dried by clean silk.


5. Check leak



The output connection pipeline or calibrated instrument leak will influence the calibrate accuracy. Can check as following mode: Open output valve, add weights on the pressure meter, let the calibrate instrument’s pressure to the specified value. Then close output valve, if the calibrated instrument indicate value keep still, then there is no leak between the pressure meter and instrument.

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