Natural Gas Flow Meter Selection

Email:sales01@cxflowmeter.com

whatsapp:008618049841995

Regarding the customer's requirement for a natural gas flow meter (RMT85 DCID 4-inch ANSI 125 FF, maximum flow rate 450 m³/h, 

requiring a Romet EVC AdEM-PTZ-Mi data processing system), our technicians recommend the DN100 gas vortex flow meter

 (US standard 150 lb flange connection, without compensation), which is reasonable. The specific analysis is as follows:

I. Selection Rationality Analysis

Flow Rate Matching: The customer's original maximum flow rate requirement is 450 m³/h. The flow rate range of the DN100 gas vortex 

flow meter is typically 16-600 m³/h (slight variations between brands), fully covering the customer's needs, and maintaining high accuracy 

in commonly used flow ranges (e.g., 200-400 m³/h).

If the original RMT85 model's flow rate range is insufficient (e.g., maximum flow rate only 400 m³/h), replacing it with the DN100 vortex 

flow meter can avoid the risk of exceeding the flow limit.

Interface Compatibility: The customer's original requirement was an ANSI 125 FF flange (US standard 150 lb). The DN100 vortex flowmeter

 typically supports US standard flange connections (such as ANSI B16.5 Class 150), allowing for direct replacement without additional 

modification.

Functional Adaptability: Romet EVC AdEM-PTZ-Mi System: This system requires a mechanical actuator or equivalent installation. The 

vortex flowmeter outputs flow data via vortex frequency signals and can directly interface with the EVC system without additional 

compensation modules (if the customer does not require temperature and pressure compensation, the "no compensation" design is

 even simpler).

No Temperature and Pressure Compensation: If the customer's operating conditions are stable (e.g., normal temperature and pressure), 

a vortex flowmeter without compensation can reduce costs; if high-precision metering is required, a temperature and pressure compensation

 module can be added later.

Economy and Maintainability: The vortex flowmeter has a simple structure with no moving mechanical parts (such as turbines or impellers),

 resulting in a long lifespan and low maintenance costs, making it suitable for long-term stable operation.

Compared to turbine flow meters (which require regular bearing lubrication) or rotary flow meters (sensitive to impurities), vortex flow

 meters have lower requirements for media cleanliness and are more suitable for natural gas applications.

II. Key Parameters to be Confirmed with the Customer

Operating Conditions

Pressure and Temperature: Confirm the natural gas operating pressure (e.g., PN16/25) and temperature range (e.g., -20℃ to +60℃) to ensure

 the flow meter material (e.g., stainless steel) and seals are compatible.

Media Cleanliness: If containing small amounts of liquid or particles, a filter must be installed or a fouling-resistant vortex flow meter must 

be selected.

Accuracy Requirements: Vortex flow meter accuracy is typically ±1.0% to ±1.5% (depending on the brand). If the customer requires higher

 accuracy (e.g., ±0.5%), an ultrasonic gas flow meter or turbine flow meter (with temperature and pressure compensation) can be 

recommended.

Output Signal: Confirm the EVC system interface type (e.g., pulse, 4-20mA, RS485) to ensure the flow meter output signal matches.

III. Calibration and Installation Recommendations

Calibration Certificate

Provide a calibration certificate issued by a third-party metrology institution (such as CNAS certification) to ensure the flowmeter complies

 with national metrology regulations (such as JJG 1029-2007 "Verification Procedure for Vortex Flowmeters").

If the customer uses it for trade settlement, a flowmeter with a precision of 0.5 class or higher should be selected, and it should be sent

 for periodic inspection.

On-site Installation and Commissioning

Straight Pipe Section Requirements: Upstream requires a straight pipe section of ≥15D, downstream requires ≥5D (D is the pipe diameter),

 avoiding interference from bends, valves, etc.

Vertical Installation: Vertical installation is preferred (fluid from bottom to top) to prevent liquid accumulation; for horizontal installation, 

ensure the pipe is not tilted.

Electrical Connection: Connect signal and power lines according to the instruction manual, and ensure proper grounding and lightning 

protection measures.

IV. Comparison of Alternative Solutions (If Customer Needs Change)

Flow Meter Type | Advantages | Disadvantages | Applicable Scenarios

Gas Turbine Flow Meter | High accuracy (±0.5%), good repeatability | Requires regular lubrication, sensitive to impurities | Trade settlement, 

high-precision metering

Gas Ultrasonic Flow Meter | Wide range ratio (1:100), no pressure loss | Higher price, sensitive to installation environment | Large diameter, 

high-pressure natural gas metering

Oval Pulley Flow Meter | Suitable for humid gas, pulsating flow | High noise, large size | Associated gas, non-trade settlement scenarios

V. Summary

The decision to recommend the DN100 gas vortex flow meter (US standard 150 lb flange connection) is reasonable, but further 

confirmation of the customer's operating parameters, accuracy requirements, and budget is needed. If the customer has no special

 requirements (such as ultra-high temperature/high pressure, extremely high precision), this solution can balance performance, cost, 

and ease of maintenance. It is recommended to provide a detailed product manual and calibration plan, and arrange for technical 

personnel to conduct an on-site inspection to ensure installation quality.

Email:sales01@cxflowmeter.com

whatsapp:008618049841995