To meet the continuous combustion characteristics of industrial gas-fired boilers, it is necessary to select suitable pressure regulators by considering their combustion features, such as large load fluctuations, high requirements for pressure stability, and continuous gas supply. Based on the combustion characteristics of boilers, this paper analyzes the appropriate types of pressure regulators and the reasons for their selection:

I. Requirements for Pressure Regulators Imposed by Core Combustion Characteristics of Industrial Gas-Fired Boilers

The combustion process of industrial gas-fired boilers must be continuous and stable. The core characteristics impose the following requirements on pressure regulators:

1. 1.High Pressure Regulation Accuracy

2. If the outlet pressure fluctuation exceeds ±5% during combustion, it may lead to incomplete combustion (reduced efficiency), flameout, or deflagration (safety risks). Therefore, the pressure regulator must control the outlet pressure fluctuation within a narrow range (typically ≤ ±2.5%).

3. 2.Wide Flow Regulation Range

4. Boilers need to accommodate a wide flow demand from low load at startup to full load (flow variation may exceed 10 times). The pressure regulator must maintain stable pressure performance over a wide flow range.

5. 3.Fast Response Capability

6. In the event of sudden boiler load changes (e.g., a rapid increase in heat demand) or inlet pressure fluctuations, the pressure regulator must adjust quickly to prevent outlet pressure surges or drops that could cause combustion interruption.

7. 4.High Reliability and Uninterrupted Gas Supply

8. Most industrial boilers operate continuously (e.g., 24/7). The pressure regulator must be capable of long-term stable operation, and a backup mechanism (such as dual-line switching) must be available in case of failure to avoid gas supply interruption.

II. Suitable Pressure Regulator Type: Pilot-Operated Indirect-Acting Regulators (Industrial Large-Flow Models)

This type of regulator is the preferred choice for industrial gas-fired boilers, as its structure and performance perfectly match the above requirements. The specific reasons are as follows:

1. Core Structure and Working Principle

Pilot-operated indirect-acting regulators consist of a main regulator and a pilot (auxiliary regulator):The pilot first senses changes in outlet pressure and performs pre-regulation, then actuates the main regulator. Through two-stage regulation, higher pressure stabilization accuracy is achieved. No external energy is required (driven by the gas pressure itself), making it suitable for industrial sites without power or dedicated control air.

2. Why It Meets the Combustion Characteristics of Industrial Boilers

• High Pressure Stabilization AccuracyThe pilot can control outlet pressure fluctuation within ±1% to ±2.5%, which is far better than the ±5%–±10% of direct-acting regulators, ensuring stable combustion.

• Wide Flow Regulation RangeThe main regulator is designed with large diameters (e.g., DN50–DN300). Combined with the precise control of the pilot, it can cover a wide range from low flow (startup condition) to high flow (full load), with a turndown ratio of over 1:20.

• Fast Response and Anti-InterferenceThe pilot is compact and highly sensitive. When inlet pressure fluctuates or boiler load changes abruptly, it can actuate the main regulator within 0.5–2 seconds, avoiding large outlet pressure deviations.

• Reliability and Uninterrupted OperationIndustrial-grade models use wear-resistant materials (e.g., stainless steel valve trims, NBR seals) with a service life of 8,000–10,000 hours. Some models support a dual parallel configuration (one operating, one standby), enabling automatic switchover to the backup line upon main line failure, completely eliminating gas supply interruptions.

III. Limitations of Other Types of Pressure Regulators

• Direct-Acting RegulatorsSimple in structure (regulated only by diaphragm and spring), but with low pressure regulation accuracy (±5%–±10%) and narrow flow range (turndown ratio typically ≤ 1:5). They are only suitable for small-capacity commercial boilers and cannot meet the wide load and high-precision requirements of industrial boilers.

• Electric Pressure RegulatorsDriven by external power. Although regulation accuracy is high, industrial sites may face power supply instability, and recovery from failure depends on external energy, which cannot guarantee uninterrupted operation. In addition, electrical components require explosion-proof design in gas environments, resulting in higher costs.

Conclusion

Pilot-operated indirect-acting pressure regulators (industrial large-flow models) are the optimal choice to meet the continuous combustion characteristics of industrial gas-fired boilers. For further improved reliability, a dual parallel configuration can be adopted to ensure continuous gas supply during regulator maintenance or failure.