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2500 Automatic Tank Gauge (ATG)

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2500 ATG

The 2500 ATG is a mechanically operated float & tape instrument that delivers continuous, inventory-grade level measurement without electrical power at the gauge head. A stainless-steel float follows product level; a perforated tape engages the gauge sprocket to drive the dial/counter at the tank side. With accuracy up to 0.2 in (4 mm) per API Chapter 3.1B, ATEX certification, and a wide range of installation kits, it has been the working standard at terminals, refineries, aviation fuel farms, and chemical plants for decades.

The gauge mounts on the tank roof or, with a ground-reading kit, at grade. When control-room visibility or temperature integration is required, the 2920 Float & Tape Transmitter digitizes the mechanical measurement and transmits level and temperature via open protocols (Modbus, GPU Bi-Phase Mark, Mark/Space, L&J Tankway). An optional Negator Cassette protects the motor and tape path to reduce scheduled maintenance.

2500 ATG
2500 ATG
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Features

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Power-free operation. The float & tape mechanism requires no electrical supply at the gauge head, making the 2500 ATG suitable for hazardous locations, remote tank farms, and sites where power infrastructure is limited or impractical.

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Inventory-grade accuracy. Up to 0.2 in (4 mm) per API Chapter 3.1B; repeatability approximately ±1/16 in (±2 mm). Suitable for custody transfer and regulatory inventory reporting.

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Flexible reading positions. Dial/counter in metric or imperial units (decimals or fractions); roof-mounted or ground-reading configurations to suit access requirements.

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Broad tank compatibility. Fixed roof, external and internal floating roof, stilling well, spheres, and bullets. For pressurized vessels, see the 2520 ATG.

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Reduced maintenance. The optional Negator Cassette simplifies motor replacement and protects internal moving parts for more consistent long-term operation.

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Digital integration ready. Connect the 2920 Float & Tape Transmitter to publish level and temperature (3-wire RTD) via Modbus, GPU/BPM, Mark/Space, or L&J Tankway — feeding SCADA, FuelsManager®, or any open-protocol monitoring system.

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ATEX certified. Approved for use in potentially explosive atmospheres (FM06ATEX0009). The full Varec gauging range, including explosion-proof transmitter options, is certified across ATEX, IECEx, and NEC divisions.

Applications

  • Terminal and Refinery Storage Tanks: Multi‑product inventories, API 650/653 fixed and floating roof designs, and custody transfer measurement under API MPMS and OIML R85.
  • Aviation Fuel Storage Systems: Jet and AV gas storage requiring power‑free, mechanically reliable level indication at hydrant pits, into‑plane fueling systems, and bulk storage - aligned with JIG Standards.
  • Chemical and Solvent Storage: Corrosive service applications with float and tape options; ATEX‑certified for hazardous atmosphere classification zones.
  • Floating Roof and Stilling Well Installations: Internal and external floating roof tanks and stilling well applications.
  • Low‑Pressure Spheres and Bullets: Spheres and bullets in low‑pressure service; for higher‑pressure applications, specify the 2520 ATG.
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Technical Specifications

Accuracy

Up to 0.2 in (4 mm) per API Chapter 3.1B; repeatability approx. ±1/16 in (±2 mm)

Measuring Range

Standard 0–60 ft (18 m); Extended up to 96 ft (29 m)

Specific Gravity

0.7 to 1.9 g/cc with correct float selection

Service Rating

Aluminum housing: atmospheric to ~2.5 PSI; Cast iron housing: atmospheric to ~14.9 PSI

Ambient Temperature

-40 °F to +185 °F (-40 °C to +85 °C) typical

Display

Dial/counter, metric or imperial (decimals or fractions); optional ground-level reading kits

Certifications

ATEX (FM06ATEX0009) for use in potentially explosive atmospheres

Digital Integration

Compatible with 2920 Float & Tape Transmitter: level, temperature (3-wire RTD); Modbus, GPU/BPM, Mark/Space, L&J Tankway

Options

Negator Cassette, interface floats, guidewires/float wells, installation kits, limit switches

Downloads

Specify the Proven Standard for Power‑free Tank Gauging.
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Specify the Proven Standard for Power‑free Tank Gauging.

Contact Cognesense to configure the 2500 Automatic Tank Gauge for your storage application - selecting the measuring range, housing, float, and mounting options to match your tank design and operating conditions. Our experts can also help you add the 2920 Float & Tape Transmitter to deliver level and temperature data to SCADA or FuelsManager without replacing your mechanical gauge, giving you inventory‑grade accuracy today with a seamless path to digital integration tomorrow.

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How accurate is the 2500 ATG?

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Up to 0.2 in (4 mm) per API Chapter 3.1B when installed and calibrated to guidelines. Repeatability is approximately ±1/16 in (±2 mm). This meets the inventory-grade accuracy standard required for API 2350 overfill prevention programs and regulatory inventory reporting under EPA SPCC.

Can the gauge be read at ground level?

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Yes. Ground-reading kits relocate the dial/counter to grade while the float, tape, and sprocket assembly remain at the tank roof. Standard practice on large storage tanks where regular roof access is restricted or impractical.

Does the 2500 ATG work on high-pressure tanks?

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The 2500 ATG is rated for low-pressure service: aluminum housing to approximately 2.5 PSI, cast iron housing to approximately 14.9 PSI. For pressurized vessels above these ratings, specify the 2520 ATG. For non-contact level measurement on high-pressure tanks, the Cognesense radar gauge range covers pressurized service.

How is the measurement digitized for SCADA or inventory software?

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Add the 2920 Float & Tape Transmitter. It mounts directly to the 2500 ATG and publishes level and temperature via Modbus, GPU Bi-Phase Mark, Mark/Space, or L&J Tankway. This makes the 2500 ATG compatible with any open-protocol SCADA system and with FuelsManager® terminal automation software from Varec.

What does the Negator Cassette do?

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The Negator Cassette protects the motor and tape path from debris and wear, simplifying motor replacement and extending service intervals. It is particularly useful on tanks with frequent product movement or in environments where contamination of the tape mechanism is a risk.

What maintenance does the 2500 ATG require?

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Periodic calibration checks per API Chapter 3.1B, inspection of the float, tape, and sprocket, and cleaning of the gauge head. The Negator Cassette option reduces the frequency of motor-related maintenance. Varec field service supports installation, calibration, and ongoing maintenance.

Summary

The 2500 Automatic Tank Gauge delivers continuous, inventory-grade level measurement for bulk liquid storage across petroleum terminals, refineries, aviation fuel farms, and chemical facilities – without electrical power at the gauge head. Its fully mechanical float and tape design operates across fixed-roof, floating-roof, stilling well, and low-pressure sphere and bullet configurations, maintaining the uninterrupted measurement record required by EPA SPCC plans and API 2350 overfill prevention standards regardless of power supply conditions or hazardous area classification.

When paired with the 2920 Float & Tape Transmitter, the 2500 publishes level and temperature data to SCADA platforms, RTUs, and FuelsManager via open protocols – connecting the mechanical gauge to the control room without replacing the installed hardware. For applications requiring tighter than 4 mm custody transfer accuracy, a radar or servo gauge is the appropriate choice; for pressurized vessels above approximately 14.9 PSI, specify the 2520 ATG.

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