---
title: "Expansion Valve"
industry: "Machinery and Equipment Manufacturing"
verification_protocol:
  urn: "URN:CNFX:ME:EXPANSION_VALVE"
  data_integrity_hash: "174e67fa8dacc6163d310918023e51cd"
  source_authority: "https://cnfx.com"
  strict_mode: true
source_identity:
  provider: "CNFX Industrial Knowledge Graph"
  index_version: "2026.Q1-Universal"
  authority_id: "URN:CNFX:ME:EXPANSION_VALVE"
  data_source_uri: "https://cnfx.com/llms/industry/machinery-and-equipment-manufacturing/product/expansion-valve.md"
  official_resource_url: "https://cnfx.com/industry/machinery-and-equipment-manufacturing/product/expansion-valve"
  is_verified_logic: true
attributes:
  spec:
    status: "config-dependent"
    typical_range: "0.5-25 bar differential pressure, -40°C to 120°C operating temperature"
    unit: "mm"
engineering_limits:
  max_safe_operating_point:
    value: 30
    unit: "bar"
    consequence: "Diaphragm fatigue failure from cyclic pressure loading exceeding yield strength of 316L stainless steel (205 MPa), refrigerant flash evaporation causing cavitation erosion at vapor quality &gt;0.9"
fmea_matrix_quantitative:
  - node_1:
      trigger: "Refrigerant contamination with &gt;500 ppm moisture content"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Install molecular sieve filter with 3Å pore size upstream, implement moisture sensor with 100 ppm alarm threshold"
  - node_2:
      trigger: "Sudden load reduction causing evaporator pressure drop below 1.5 bar"
      severity: 8
      occurrence: 3
      detection: 4
      mitigation_protocol: "Integrate PID controller with 0.5-5.0 bar pressure transducer feedback, minimum opening position at 15% of total stroke"
bom_nodes:
  valve-body:
    type: "part"
    urn: "URN:CNFX:ME:VALVE_BODY"
    interface_type: "physical-logic-coupled"
  orifice:
    type: "component"
    urn: "URN:CNFX:ME:ORIFICE"
    interface_type: "physical-logic-coupled"
  thermal-bulb:
    type: "component"
    urn: "URN:CNFX:ME:THERMAL_BULB"
    interface_type: "physical-logic-coupled"
  diaphragm:
    type: "component"
    urn: "URN:CNFX:ME:DIAPHRAGM"
    interface_type: "physical-logic-coupled"
  spring:
    type: "component"
    urn: "URN:CNFX:ME:SPRING"
    interface_type: "physical-logic-coupled"
manufacturing_compliance:
  - standard: "ISO 5149:2014 (REFRIGERANTS AND REFRIGERANT SYSTEMS)"
    scope: "Verified Engineering Specification"
  - standard: "ANSI/ASHRAE 15-2019 (SAFETY STANDARD FOR REFRIGERATION SYSTEMS)"
    scope: "Verified Engineering Specification"
  - standard: "EN 378:2016 (REFRIGERATING SYSTEMS AND HEAT PUMPS - SAFETY AND ENVIRONMENTAL REQUIREMENTS)"
    scope: "Verified Engineering Specification"
url: "https://cnfx.com/llms/industry/machinery-and-equipment-manufacturing/product/expansion-valve.md"
on_chain_sovereignty:
  contract_standard: "ERC-721-Industrial"
  metadata_hash: "5e46a31818a3236483b3d480d1a48f9a8db8d30807e7cb3e41b9f02bb651824c"
  royalty_logic: "IPFS-CID-REQUIRED"
  mint_status: "logic-verified-ready"
version: "3.3.4-EXTREME-SOVEREIGN-WEB3"
---

# Industrial Specification: Expansion Valve

## 1. Technical Definition
A refrigerant flow control device that regulates the amount of liquid refrigerant entering the evaporator.

## 2. Engineering Reasoning & Causal Matrix
> **Operational Intelligence**: Designed for **0.5-25 bar differential pressure, -40°C to 120°C operating temperature**. Failure boundary: **Differential pressure exceeding 30 bar causes diaphragm rupture, superheat below 2°C leads to liquid slugging**, Mechanism: **Diaphragm fatigue failure from cyclic pressure loading exceeding yield strength of 316L stainless steel (205 MPa), refrigerant flash evaporation causing cavitation erosion at vapor quality &gt;0.9**.

### 2.1 Analytical Physics Model
Governed by the **Darcy-Weisbach Pressure Drop**:

> **Primary Equation**: $\Delta P = f \cdot \frac{L}{D} \cdot \frac{\rho v^2}{2}$  
> **Engineering Impact**: Critical for sizing CIP (Clean-In-Place) pump heads.

| Symbol | Variable Definition | Localized Reference |
| :--- | :--- | :--- |
| f | Friction Factor | Engineering Constant |
| L | Pipe Length | Engineering Constant |
| v | Velocity | Engineering Constant |

### 2.2 FMEA (Failure Mode & Effects Analysis)
| Event Trigger | Severity | Failure Mode | Mitigation Strategy |
| :--- | :--- | :--- | :--- |
| Refrigerant contamination with &gt;500 ppm moisture content | 8 | Thermal expansion element corrosion and loss of superheat control | Install molecular sieve filter with 3Å pore size upstream, implement moisture sensor with 100 ppm alarm threshold |
| Sudden load reduction causing evaporator pressure drop below 1.5 bar | 8 | Valve hunting with ±3°C superheat oscillation | Integrate PID controller with 0.5-5.0 bar pressure transducer feedback, minimum opening position at 15% of total stroke |

## 3. Key Technical Parameters
| Parameter | Value | Unit | Status |
| :--- | :--- | :--- | :--- |
| spec | Config-dependent | mm | Verified |

## 4. System BOM & Knowledge Routing
### Core Components (Recursive Links)
- [Valve Body](https://cnfx.com/llms/industry/machinery-and-equipment-manufacturing/product/valve-body.md) `(Standalone System)`

### Industrial DNA Context (De-duplicated)
**Complementary Dependencies**: **Compressor**, **Evaporator**, **Condenser**  
**Downstream Applications**: Commercial Refrigeration Unit, HVAC System, Industrial Chiller  

## 5. Engineering Risks & FAQ
- **Caution**: 
- **Caution**: 
- **Caution**: 

### Q: What is the primary function of an expansion valve in refrigeration systems?
**A**: The expansion valve regulates the flow of liquid refrigerant into the evaporator, controlling pressure and temperature to ensure efficient cooling in industrial machinery.

### Q: Which materials are commonly used in industrial expansion valves and why?
**A**: Brass, stainless steel, and copper are standard for their corrosion resistance, durability, and thermal conductivity, making them ideal for harsh industrial environments.

### Q: How do the BOM components like diaphragm and thermal bulb work together?
**A**: The thermal bulb senses evaporator temperature, signaling the diaphragm to adjust the orifice opening via the spring, creating a precise feedback loop for refrigerant flow control.

## 6. Manufacturing Compliance
- ISO 5149:2014 (REFRIGERANTS AND REFRIGERANT SYSTEMS)
- ANSI/ASHRAE 15-2019 (SAFETY STANDARD FOR REFRIGERATION SYSTEMS)
- EN 378:2016 (REFRIGERATING SYSTEMS AND HEAT PUMPS - SAFETY AND ENVIRONMENTAL REQUIREMENTS)

---
### 🛠️ Engineering Resource Access
🔗 **[Full Specification: Expansion Valve](https://cnfx.com/industry/machinery-and-equipment-manufacturing/product/expansion-valve)**

### 🌐 Knowledge Graph Topology
> **Node Status**: Verified Engineering Spec
> **Connectivity**: Linked to **5** standalone system nodes
> **Global Context**: Part of a 5,814 node industrial cluster within the CNFX Graph

> **Reference ID**: EXPANSION_VALVE | **Authority**: CNFX-2026-ST-001 | **Fingerprint**: e507eb33
