未进气状态：

       一级膜片在一级弹簧预应力的作用下，使一级杠杆组中的杠杆与进气阀芯的钢球保特一定的间隙，阀口处于常开状态。
       二级膜片在二级弹簧的作用下，将二级杠杆一端下移，使二级阀口处于常开状况。
       三级杠杆在弹簧张力作用下，使三级杠杆与阀座处于常闭。

进气及工作状态：

       当25Mpa天然气通过进气阀芯组进入一级减压腔使一级膜片逐步上移，当一级减压腔气压达到一定值，膜片的推力完全克服一级弹簧的预紧力时，作用于杠杆的合力矩使阀芯关闭阀口。燃气流量随发动机负荷变化而变化，在弹簧与膜片相互作用下，阀口随时变化开度，输出压力稳定在0.4～0.6Mpa，完成一级减压。
       经过一级减压的气体进入二级减压腔，随发动机负荷的变化，二级膜片通过二级传动杆带动二级杠杆的阀片（阀门）调节二级阀口的开度。随着三级减压腔流量的变化不断改变二级阀口的开度，保特输出压力在0.08Mpa左右。
       在只进气状态下，二级减压腔的气体克服三级调节弹簧的张力，打开三级阀座进入三级减压腔，使三级减压腔的压力稳定在0.3～0.5KPa。当发动机起动时，有0.5Kpa的低压天然气进入发动机，便于起动。发动机运转产生真空吸力将三级膜片吸向下方，三级膜片组推动三级杠杆，打开三级阀座，二级减压腔的气体进入三级减压腔，混合气由低压出气口经低压管动力阀进入发动机。三级阀口的开度随发机负荷吸气负压的变化而变化，以满足发动机的各种工况所需要的燃气流量。

减压器各级背压腔：

       一级背压腔大气通孔在一级减压器上盖上；二级背压腔大气通道在二级内盖上；三级背压腔大气通孔在三级底盖侧面上。要减压器工作正常须保持背压腔大气通孔畅通。

CNG天然气调压阀

CNG天然气调压阀，也常被称为减压阀 (Pressure Reducing Valve) 或调压器 (Regulator)，是压缩天然气（CNG）系统中一个至关重要的装置。它的核心作用是自动地将来自高压储气瓶或不稳定上游的气体压力，降低并稳定到一个适合下游设备使用的、安全的压力水平。

其基本工作原理是通过感应出口压力的变化，自动改变阀门内部启闭件的开度，从而调节燃气流量，以维持出口压力的稳定。 从流体力学角度看，它是一个局部阻力可以变化的节流元件。 主要可分为直接作用式和间接作用式两种。

CNG天然气调压阀主要特点

· 压力稳定：能够将不稳定的上游压力准确地降低并稳定在所需的出口压力，保持下游设备平稳运行。

· 高流通能力：设计上注重高流量，以满足发动机等设备的燃气需求。

· 安全稳定：通常内置安全释压阀，在压力异常升高时自动泄放，保障系统安全。 部分型号还集成有高压切断电磁阀，在紧急情况下快速切断气源。

· CNG天然气调压阀多种材质与认证：阀体常采用黄铜、不锈钢等材质以适应不同环境。 许多产品通过了如NGV 3.1、ECE R110、ISO 15500等标准认证，确保在车辆等移动设备上的使用安全。

· 集成化设计：一些好的调压阀会集成内置过滤器（如40微米烧结过滤器）以净化燃气， 并可能设计有换热结构（如使用发动机冷却液）来应对CNG减压过程中产生的低温效应。

CNG天然气调压阀主要技术参数

下表列举了不同型号CNG调压阀的一些典型技术参数，具体数值因型号和应用差异很大：

参数名称 典型范围/示例 参考来源

入口压力 250 - 6000 psig (约1.72 - 414 bar)

出口压力范围 0 - 5000 psig (约0 - 345 bar) 或 28 - 150 psig (约193 - 1034 kPa)

流通能力 (Cv值) 例如 Cv = 0.80 或 2.0

适用介质 压缩天然气 (CNG)，及其他弱腐蚀性、无杂质气体

工作温度 例如 -40°C 至 125°C (发动机罩下环境)

连接端口 SAE、NPTF、MS33649等，尺寸如1/4", 1/2", 3/4"

CNG天然气调压阀典型应用领域

· 天然气汽车 (NGV)：包括公交车、叉车、出租车及其他使用CNG作为燃料的车辆，是CNG燃料系统的核心部件之一。

· 压缩天然气 (CNG) 灌装站：

· CNG天然气调压阀灭火设备：

· 工业燃气供应系统：用于需要稳定气压的工业流程。

选型、安装与维护要点

· 选型：需要关键参数，如进口压力范围、所需出口压力、流量、介质性质、连接方式及阀体材质等。 新选型需提供这些参数，老设备替换则需提供原有调压器的确切型号和出口压力。

· CNG天然气调压阀安装：

  · 安装前需对管道进行试压和吹扫，确保密封与清洁。

  · 通常要求水平垂直安装在管道上，并注意阀体指示的介质流向。

  · 调压阀前后建议安装隔离阀、压力表，并设置旁通管路和安全放散阀以便于观察、维护和保持安全。

· CNG天然气调压阀维护：

  · 燃气需经过滤，定期清洗或更换滤芯以防止杂质损坏调压器。

  · 部分设计允许在线维修。

�� Complete English Translation

Product Overview of CNG Natural Gas Pressure Regulator

The CNG natural gas pressure regulator, often referred to as a Pressure Reducing Valve  simply Regulator, is a critical component in Compressed Natural Gas (CNG) systems. Its primary function is to automatically reduce the high  potentially fluctuating pressure  gas storage cylinders  upstream sources to a lower, stable,  safe pressure suitable for downstream equipment.

It operates on the basic principle of automatically adjusting the opening of an internal closure member by sensing changes in the outlet pressure, thereby regulating the gas flow to maintain a constant outlet pressure.  a hydrodynamic perspective, it acts as a throttling element with variable local resistance. Main types include direct-acting  indirect-acting regulators.

Key Features

· Pressure Stabilization: Capable of precisely reducing  stabilizing unstable inlet pressure to the required outlet pressure, ensuring smooth operation of downstream equipment.

· High Flow Capacity: Designed for high flow rates to meet the fuel demands of engines  other equipment.

· Safety  Reliability: Often equipped with an integrated relief valve to automatically vent pressure in case of overpressure, ensuring system safety. Some models also integrate a high-pressure shut-off solenoid valve for rapid fuel cut-off in emergencies.

· Various Materials  Certifications: Valve bodies are commonly made of brass, stainless steel, etc., to suit different environments. Many products comply with international standards like NGV 3.1, ECE R110,  ISO 15500, ensuring safety for use in vehicles  other mobile applications.

· Integrated Design: Advanced regulators may incorporate a built-in filter (e.g., 40-micron sintered filter) to clean the gas,  may feature a heat exchange structure (e.g., using engine coolant) to address the cooling effect during CNG pressure reduction.

Main Technical Parameters

The table below lists some typical technical parameters for different models of CNG pressure regulators. Specific values vary greatly depending on the model  application:

Parameter Typical Range / Example Reference

Max. Inlet Pressure 250 - 6000 psig (approx. 1.72 - 414 bar)

Outlet Pressure Range 0 - 5000 psig (approx. 0 - 345 bar)  28 - 150 psig (approx. 193 - 1034 kPa)

Flow Capacity (Cv) e.g., Cv = 0.80  2.0

Applicable Medium Compressed Natural Gas (CNG),  other weak corrosive, impurity-free gases

Operating Temperature e.g., -40°C to 125°C (under-hood environment)

Connection Ports SAE, NPTF, MS33649, etc., in sizes like 1/4", 1/2", 3/4"

Typical Applications

· Natural Gas Vehicles (NGV): Including buses, forklifts, taxis,  other vehicles using CNG as fuel. It is a core component of the CNG fuel system.

· CNG Filling Stations:

· Fire Suppression Equipment:

· Industrial Gas Supply Systems: Used in industrial processes requiring stable gas pressure.

Selection, Installation,  Maintenance Guide

· Selection: Key parameters are required, such as inlet pressure range, desired outlet pressure, maximum flow rate, medium properties, connection type,  valve body material. New selections need these parameters; replacements require the exact model number  outlet pressure of the original regulator.

· Installation:

  · Pipes must be pressure-tested  purged before installation to ensure tightness  cleanliness.

  · It should generally be installed horizontally  vertically in the pipeline, paying attention to the flow direction marked on the valve body.

  · It is advisable to install isolating valves, pressure gauges upstream  downstream of the regulator,  include a bypass line  a safety vent valve for observation, maintenance,  safety.

· Maintenance:

  · Gas must be filtered; regularly clean  replace the filter element to prevent damage  impurities.

  · Some designs allow for in-line maintenance.