I. Core Steps of Movement Assembly
1. Precision assembly system for the case and the plug plate
(1) Structural matching design
The case is made of high-strength engineering plastic through injection molding. The bottom is equipped with stepped installation holes of Φ8±0.05mm, and the inner wall is precisely processed by a CNC machine tool to form a 2° guiding taper. The insert plate is formed by stamping 304 stainless steel. The edge is designed with 12 groups of evenly distributed dovetail teeth, and the tooth pitch accuracy is controlled within 0.1mm.
(2) Key points of assembly process
① Pre-installation inspection: Use a dial indicator to check that the flatness of the insert plate is ≤0.02mm
② Alignment operation: Tilt the insert plate 45° and insert it into the opening slot of the case, then rotate it clockwise 15° to the locked position
③ Pressure test: Apply an axial pressure of 50N to verify the bite strength
2. Precision gear shaft transmission system
(1) Core component parameters
Main shaft material: SUS420 stainless steel
Bearing structure: Double gemstone bearing (corundum material)
Pointer system: Aluminum alloy balanced pointer (counterweight error ≤0.01g)
(2) Installation process flow
The operation requirements of the steps and the detection standards
① The pre-installed silicon-based grease on the shafting system has a grease coverage rate of no less than 90%
② The preload force for the axial positioning installation of the wave spring gasket is 0.5±0.1N·m
③ Radial limit adjustment: The axial movement of the nylon limit block is ≤0.03mm
II. Error-proofing Design Enhancement Plan
1.Double insurance institution
(1) Primary limit: Three 120° evenly distributed ABS limit columns are injection molded in the mold at the top of the case
(2) Secondary protection: A ring-shaped groove is machined at the end of the gear shaft, and an elastic retaining ring is installed as a match
2. Innovate and stabilize the structure
The limit slot adopts a composite design of “V-shaped guide Angle + slightly convex surface”, and the interference fit with the elastic block is controlled within the range of 0.05-0.08mm. Laboratory verification shows that this structure can enhance the anti-vibration performance of the plug-in board by 40%.
III. Pre-installation Preparation Standards
1. Pipeline pretreatment standards
(1) Flushing requirements:
Newly installed pipes: Flush with 0.3MPa pressure water for ≥30 minutes
Pipeline renovation: Add magnetic filters for treatment
(2) Impurity control:
The residue content should be less than 5mg/m³ when tested with a 100μm filter screen
2. Installation Technical Specifications
Environmental conditions:
Ambient temperature: 5-40℃
Relative humidity: ≤85%RH
(2) Operating Specifications:
① It is strictly prohibited to directly hold the watch body with pipe clamps
After installation, three full-scale water flow tests need to be conducted
③ Before installing the lead seal, the error should be checked (≤±2%).
IV. Key Points of Quality Control
1.Key inspection items
Sealing test: Maintain a water pressure of 0.6MPa for 15 minutes
Start-up flow test: ≤4L/h
Measurement accuracy test: The error in the flow section Q2-Q4 is ±1%
2. Compliance with industry standards
Strictly implement the technical requirements of GB/T 778.1-2018 “Drinking Cold Water Meters and Hot Water Meters”, and the key components have passed ISO 4064 Grade B certification.
(Note: This regulation is applicable to the installation of the rotor type cold water meter movement of DN15-DN40. For special models, please refer to the manufacturer’s technical manual.