The low-pressure switch setting principle

Here is the professional English translation of the low-pressure switch setting principles:

️ I. Core Operating Principle

Low-pressure switches operate through ‌hydraulic-mechanical-electrical conversion‌:

Pressure Sensing‌:

Pipe network fluid pressure acts on internal diaphragm/piston

Springs drive mechanical displacement to trigger switch when pressure drops

Signal Conversion‌:

Displacement activates micro switch, converting motion to electrical signal

Normally Open (NO) contact closes to complete circuit, initiating pump start signal

Dual Output‌:

Two independent contacts: One interlocks pump start, the other feeds back to fire control panel

(Insert schematic: Micro switch & diaphragm internal structure)

🔌 II. Electrical Control Logic

Terminal Type‌ ‌Function‌ ‌Connection Target‌

Common (COM)‌ Reference potential 24V power input

NO (Normally Open)‌ Closes when pressure low Pump control cabinet start terminal

NC (Normally Closed)‌ Closes normally (optional) System status monitoring

Pump Interlock Logic‌: Pressure below setpoint → NO-COM conducts → Directly triggers pump start (independent of fire panel)

🔧 III. Threshold Setting Mechanisms

Mechanical Adjustment‌

Knob Calibration‌:

Adjust spring preload: Clockwise ↗️ increases pressure, counterclockwise ↘️ decreases

Secured by hex bolts to prevent vibration loosening

Differential Control‌:

Start value (e.g., 0.05MPa) and stop value (e.g., 0.15MPa) must maintain ≥0.05MPa difference

Electronic Configuration‌

Long-press setting key to enter programming mode

Use ▲/▼ keys to adjust start pressure (e.g., ‌0.03MPa‌) and stop pressure (e.g., ‌0.12MPa‌)

Save and switch to operational mode to activate settings

(Insert comparison card: Different switch operation interfaces)

⚠️ IV. Critical Installation Standards

Location Requirements‌:

Must be installed on ‌main discharge pipe‌ of fire pump to directly sense network pressure

Range Selection‌:

Range ≥1.6MPa and ≥2× design pressure

Wiring Protection‌:

Pump interlock wires require ‌24V relay‌ isolation from high voltage

Metal housings must be grounded for EMI protection

🔄 V. Workflow Example (Fire Protection System)

mermaid

Copy Code

graph LR

A[Pipe pressure drops] --> B[Diaphragm actuates micro switch]  

B --> C{NO contact closes}  

C --> D[Direct pump start]  

C --> E[Signal to fire control panel]  

(Workflow basis: Fire protection standards)

Post-commissioning‌: Simulate 3 pressure cycles to verify actuation consistency

(Technical diagrams and multimedia placeholders retained)