Pressure Detection

Fast, Reliable Protection Against Sudden Pressure Events

Pressure Detection devices provide essential protection for transformers by detecting dangerous, fast‑rising internal pressure changes that can signal a developing fault. The Qualitrol 900/910 Rapid Pressure Rise Relays (RPRR) use patented mechanical bellows technology to identify sudden pressure events and trigger alarms or trips before severe tank damage occurs. With over 50 years of proven field performance and modern mounting options, these relays safeguard critical assets across a wide range of transformer designs.

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Qualitrol 900-910 Rapid Pressure Rise Relays (RPRR)

Application Overview

Rapid Pressure Rise Relays are used in transformer oil or gas spaces to detect internal faults that generate rapid pressure spikes. Unlike devices that respond to absolute pressure, these relays react only to the rate of pressure rise, ensuring accurate operation even under normal load, temperature variation or vibration. The 900 model is used in oil spaces, while the 910 model is calibrated for gas space applications. They are suitable for both new installations and retrofits across utility, industrial and generation environments.

KIT‑013‑1 Field Test Kit

Contains pressure bulb, gauge, cable, tools, instructions and integrated test lights
Provides simple GO/NO‑GO confirmation while RPRR is mounted
Rugged case with shoulder strap for field use

What We Solve For

Transformers can experience internal faults that escalate within milliseconds, creating sudden pressure surges capable of rupturing tanks, endangering personnel and causing extensive outages. Pressure Detection devices address these risks by:

Detecting rapid pressure rise events early based on rate‑of‑change
Preventing nuisance trips from normal pressure fluctuations
Withstanding vacuum and overpressure without damage
Triggering alarms or trips that isolate the transformer before catastrophic failure

This results in safer operation, reduced asset loss and improved network reliability.

TECHNICAL

Features & Functionality

Functionality & Options

Oil or Gas Variants:
900 Series → Oil space
910 Series → Gas space
Switching:
Snap‑action SPDT switch used for alarm or trip circuits.
Mounting Options:
Flange mounting or 2½"-8 NPT threaded mounting; universal horizontal or vertical orientation.

Accessories:

Seal‑in relay (909‑300): Latches momentary events; VAC/VDC configurable; dual outputs; hazardous‑location certified.

Factory test fixture (FIX‑601): Supports calibration verification in manufacturing/repair shops.

KIT‑013‑1 Field Test Kit: Portable case with gauge, pressure bulb, power supply, test lights and instructions for simple field verification.

Environmental Protection:
IP65 enclosure; C5‑M corrosion‑resistant coating option for harsh conditions.
Electrical Connections:
QUALITROL, ANSI or military connectors; terminal box or test‑button option.

Key Technical Specifications

Mounting: Vertical or horizontal
Pressure Range: –14.7 to +20 PSIG (sensing bellows)
Materials: Die‑cast aluminum housing; stainless‑steel hardware; Viton O‑ring; nickel‑plated brass bleed valve
Switch Type: SPDT snap‑action
AC Rating: 10 A @ 120/240/480 VAC
DC Rating: 0.5 A @ 125 VDC; 0.25 A @ 250 VDC
Dielectric Strength: 1500 VAC for 1 minute
Temperature Range: –40°F to 180°F (standard); –67°F option
Ingress Protection: IP65
Vibration: Unaffected at 50/60 Hz or their multiples

EXPERIENCE

Our Projects featuring Our Transformers

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For tailored advice on whether this solution suits your network, please connect with our team here.

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ADVANTAGES

Why Choose Qualitrol Pressure Detection Products

The Qualitrol Pressure Detection products were designed to detect sudden, dangerous pressure rises inside transformers, enabling fast protective action that prevents severe tank damage and operational downtime.

Accurate Detection When It Matters

The relay activates only when pressure rises rapidly, ensuring dependable operation during internal faults while avoiding false trips from normal transformer behavior.

Built for Both Oil & Gas Applications

With configurations for oil (900 Series) and gas (910 Series) spaces plus flexible mounting options, it integrates easily into a variety of transformer designs.

Easy, Reliable Field Testing

The KIT‑013‑1 field test kit enables straightforward verification of relay functionality, helping operators maintain confidence in their protection system without removing the device from service.

IMPLEMENTATION

Services & Support

Insulect offers comprehensive services and support for the products we manufacture and specialise in, enhancing value for local utilities, major energy users, equipment manufacturers, and service operators.

LOCAL TECHNICAL TEAM

Our local technical team provides exceptional support and expertise, ensuring quick response times and personalised service to tackle any challenges that may arise during project execution.

ENGINEERING DESIGN

Our team utilises advanced technology and industry knowledge to develop innovative and efficient high-voltage switchgear solutions, customised to fit the unique requirements of each project.

PROCUREMENT & LOGISTICS

We facilitate smooth procurement and logistics processes by sourcing from trusted, proven partners and coordinating timely deliveries, ensuring projects remain on schedule and within budget.

TESTING & COMMISSIONING

Professional testing and commissioning support ensure that every high-voltage switchgear system functions safely and reliably, adhering to all regulatory standards and client expectations.

TURNKEY PROJECT DELIVERY

We are able to oversee every phase from concept to completion, providing comprehensive solutions that simplify complex projects and ensure successful outcomes.

FACTORY VISITS

We facilitate client visits to our local manufacturing sites here in Australia, as well as overseas, for initial inspection as well as factory acceptance testing.