Piston Water Meter Test Bench

Piston Water Meter Test Bench

Basic Information

1. Device flow range: (20-6300)L/h; 

2. Uncertainty of the device: ≤0.2% (k=2) 

3. Pressure range: 0- 2.5MPa; 

4. Ambient temperature: 15-30℃; 

5. Relative humidity: (45% -75%); 

6. Atmospheric pressure: (86-106)kpa; 

7. Power supply voltage: 400V±5%, 50HZ; 

8. Air pressure: (3.5-6)bar; 

9. Collection method: image recognition; 

10. Equipment power: water pump 1.8KW, heating 6KW; 

11. Number of inspection meters: Ultrasonic meters (DN15: 10 DN20: 10 pcs DN25: 6 pcs); 

12. Equipment size: length, width and height (5800 mm *650 mm *2000mm) 

13.The working pressure of the device: 0-1MPa; 

14.The working temperature of the device: 5-85℃ 

15.Communication interface: M-BUS, RS485; 

16.Control system: Siemens PLC, industrial touch screen; The verification process is automated, with functions such as visual interface control, automatic data storage, and report generation.

Device composition

1. Piston composition The active piston liquid flow standard device is mainly composed of a frame, a piston rod, a piston cylinder, a motor, a ball screw, a supporting optical axis, a sensor, a protective shell, etc.                        The piston rod is in close contact with the piston cylinder through the Y-shaped seal ring, and the three together form a sealed cavity. The movement of the piston rod is realized by the servo motor, coupling, ball screw, supporting optical axis, etc., the piston rod and the ball screw The rod is connected by a screw nut, and the direction of movement is controlled by a servo motor and a ball screw. A suction pneumatic valve and a drainage pneumatic valve are installed at the outlet of the piston cylinder. The suction pneumatic valve is connected to the water tank, and the drainage pneumatic valve is connected to the meter pipeline. Install high-precision temperature and pressure sensors.

2.  Control system hardware characteristics The control system is mainly composed of industrial computer, PLC control system, servo motor, grating ruler, various temperature and pressure sensors, pneumatic ball valve, platform software, etc. The industrial computer has strong anti-interference performance, which can make the verification process more stable and reliable; PLC and servo motors adopt internationally renowned brands with high precision and high reliability, and the control and data processing software are written in accordance with the relevant national verification regulations.

   
   

   
   

   (1) Grating ruler The standard cumulative flow of the active piston liquid flow standard device is the product of the piston's internal cross-sectional area and the piston displacement in the time period. Therefore, the accurate measurement of the piston displacement is one of the key factors to reduce the uncertainty of the device. In order to improve the accuracy of displacement measurement, this device uses a grating ruler to measure the displacement of the piston. The output signal of the grating ruler is an AB quadrature signal, which has been increased by 4 times on the basis of the original accuracy.                                                                                                                                                                                                                              

   (2) Servo motor The driving component of this servo system is a Panasonic servo motor. The servo motor converts the voltage signal into torque and speed to drive the control object. Changing the voltage signal can change the speed and direction of the servo motor. The servo has a built-in 23-bit encoder, which has higher control accuracy. The servo system accurately pushes the piston displacement according to the instantaneous flow and quantitative signal sent by the host computer. The servo motor has a large starting torque, a wide operating range, no rotation phenomenon, and positioning accuracy. Advanced features, widely used in various automation control systems.

   
   

   (3) Sensor The sensors mainly include temperature sensor and pressure sensor, which are located at the water outlet of the piston cylinder, respectively used to measure the temperature and pressure of the liquid, and then transmit the information to the PLC and software system in time. Sensors are important components for collecting analog quantities such as temperature, pressure, and humidity. Their accuracy and performance will directly affect the accuracy of the device's measurement results. Therefore, it is necessary to integrate various factors and choose the most cost-effective sensor product. In this device, the temperature measurement range of the temperature sensor is (0～100)ºC, and the accuracy grade is not lower than A grade; the pressure measurement range of the pressure sensor is (0～1.6) MPa, and the accuracy grade is not lower than 0.5%.

   
   

   (4) PLC control system The PLC control system of this device adopts Siemens S7200smart system, adopts ladder diagram programming language, and mounts analog input and output modules to collect and control temperature and pressure signals. PLC is essentially an industrial control computer that uses programmable memory to store and execute instructions such as logical operations and sequential operations, and through digital and analog input and output to control machinery or production processes, the interface between PLC and industrial processes It has the advantages that ordinary computers do not have, and PLC itself has a better programming language suitable for control requirements. This device is made in accordance with CE safety standards and has many protections and sound and light alarms, such as low air pressure alarm, low water tank level alarm, meter not in place alarm, piston over temperature alarm, piston over pressure alarm, piston limit alarm, etc.