Capsule Pressure Gauge for Low Pressure Gas

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Product Overview

Our Capsule Pressure Gauges are precision instruments engineered exclusively for the accurate measurement of very low pressures — from as little as 1 mbar up to 600 mbar — where the standard Bourdon tube lacks the sensitivity to produce a reliable reading. The sensing element is a corrugated metallic capsule (or stack of capsules) that expands and contracts with extraordinary sensitivity to minute pressure changes, translating even the smallest differential into a clear, full-scale dial deflection. These gauges are the instrument of choice for measuring draft pressure in furnaces and boilers, gas line supply pressure, filter differential pressure in low-resistance HVAC systems, and instrument air pressure in control panels.

Technical Specification Sheet

Parameter	Detail
Pressure Range	0–1 mbar up to 0–600 mbar (positive, negative/vacuum, compound)
Accuracy Class	±2.5% or ±1.6% of full scale
Nominal Size	DN 100 mm (4"), 150 mm (6")
Capsule Material	Stainless Steel 316L (standard) or Copper Alloy
Case Material	Stainless Steel 304 or Steel (black finish)
Process Connection	G1/4, G1/2 or NPT1/4, NPT1/2 (bottom or back)
Scale Units	mbar, Pa, mmH₂O, inH₂O, mmWC (customizable)
Protection Rating	IP54 (standard), IP65 (optional)
Overpressure Protection	Up to 3× full scale (model dependent)

Key Features

Corrugated capsule sensing element provides high sensitivity to very low pressures (1–600 mbar) far beyond the practical range of Bourdon tube instruments.
Available with scale graduations in mbar, Pa, mmH₂O, mmWC, and inH₂O to match process engineering documentation without unit conversion errors.
Stainless steel 316L capsule option provides compatibility with mildly corrosive gas streams including humid air, carbon dioxide, and natural gas with trace H₂S content.

Typical Use Cases

Gas Burner & Combustion Systems: Monitoring gas supply and nozzle pressure at very low mbar levels to ensure correct air/fuel ratio and stable combustion.
Industrial & Utility Boilers: Draft gauge measurement of furnace negative pressure (draft) and flue gas back-pressure to optimize combustion efficiency.
HVAC Air Handling Units: Low differential pressure measurement across air filters, coils, and dampers where pressure drops are below 50–200 Pa.
Laboratory Gas Supply: Precise indication of low-pressure inert and specialty gas supply to analytical instruments.
Cleanroom & Laminar Flow Systems: Monitoring the very low positive or negative pressure differential required to maintain cleanroom integrity and directional air flow.

Competitive Benefits

True Low-Pressure Sensitivity: The capsule element detects pressure changes invisible to standard gauges, providing full-scale dial deflection at ranges as low as 0–10 mbar — a fundamental physical advantage no Bourdon tube can match.
Multi-Unit Scales: Gauges can be supplied with dual-scale dials (e.g., mbar and mmH₂O simultaneously), eliminating field conversion and unit confusion in international project documentation.
Overpressure Tolerance: Despite measuring in the millibar range, the capsule design withstands accidental overpressure of up to 3× full scale without permanent zero shift or element damage.
Dry Gas Compatible: Unlike liquid-filled gauges that can develop leaks at very low pressures, the dry capsule instrument is optimized for gaseous media and will not contaminate gas streams with fill fluid.
Compact Installation Footprint: The same DN100 or DN150 standard case size as conventional gauges allows direct replacement on existing panel cut-outs and manifold connections.

Payment and Shipping Details

We accept T/T, L/C at sight, and Western Union for international orders. Standard shipping terms are FOB Shanghai/Ningbo or EXW Wuxi. Standard capsule gauge models in common mbar ranges (0–10 to 0–600 mbar) are available for dispatch within 7–10 working days. Special units (mmH₂O or inH₂O scale, stacked capsule designs for sub-1 mbar) require 15–20 working days. All instruments are zero-point and full-scale tested before shipment, and calibration certificates are available on request.

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Capsule Pressure Gauge for Low Pressure Gas Manufacturers

Wuxi Huihua Special Instrumentation Co., Ltd. was established in December 2001, the registered capital is 5 million yuan, the existing staff of more than 50 small and medium-sized joint-stock enterprises.
The company specialises in the production of various types of special instruments, alternative to the localisation of imported instruments.To seismic pressure gauge, seismic electric contact pressure gauge, stainless steel pressure gauge, diaphragm corrosion-resistant pressure gauge, marine pressure gauge and other series as the main products. On the basis of field instruments, we have developed various kinds of pressure transmitters, pressure controllers, digital pressure gauges and so on. There are more than 30 series and 3000 specifications. Products are widely used in petroleum, chemical, paper, metallurgy, mining, chemical fibre, electric power, food, environmental protection, rubber and plastic, hydraulics and many other industries, and more than 2,000 domestic customers to establish a friendly relationship with the national large and medium-sized enterprises to establish a good partnership, won the majority of users praise, and set up a corporate brand image.