Rubber Cones / Square Section Rubbers

  • Product Code: Rubber Cones

John Moncrieff — Rubber Cones & Square Section Rubbers for Boiler Applications

At John Moncrieff Ltd, we supply a wide range of high-quality rubber cones and square section rubbers engineered to provide reliable sealing for glass tubes in a variety of boiler applications.

These precision-made components are critical for preventing leaks, maintaining pressure integrity, and ensuring optimal boiler performance.

Key Features

  • Superior Sealing: Designed to form a secure, leak-free seal around glass tubes — preventing fluid loss and minimising energy waste.
  • Durability: Manufactured from premium materials, our rubber components deliver long-lasting performance in high-temperature, high-pressure environments.
  • Ease of Installation: Engineered for quick and simple fitting, reducing downtime during maintenance or replacement.

Available Materials

  • Neoprene Rubber: A versatile material ideal for general-purpose sealing applications.
  • Viton® (FKM): Offers exceptional resistance to chemicals, oils, and high temperatures — perfect for demanding industrial environments.

At John Moncrieff Ltd, we can help you select the right rubber seal for your boiler system. Our team of experts is ready to assist you in choosing the best material, size, and specification for your application.

Technical Downloads:


Standard Tank Gauge

Standard Tank Gauge

SKU: Standard Tank Gauge

Standard Tubular Level Gauge The John Moncrieff Ltd Standard Tubular Level Gauge is designed for reliable and accurate level monitoring on tanks and sealed vessels. Availab...

Quickmount Tank Gauge

Quickmount Tank Gauge

SKU: Quickmount Tank Gauge

Quickmount Tank Level Gauge The John Moncrieff Ltd Quickmount Tank Level Gauge is our most popular unit — engineered for general industrial use where reliability, serviceab...

Boiler Water Level Gauge

Boiler Water Level Gauge

SKU: Boiler Water Level Gauge

Our standard Boiler and Water Level Gauge is offers a robust design suitable for lower pressure Boilers and General water Level applications. Auto Shut off Valves as Standard, Lever Operated, Superior...

Marine Gauge Push Button

Marine Gauge Push Button

SKU: Marine Gauge Push Button

The Marine gauge is designed for use within the marine and offshore industries. Due to its tubular design this gauge is suitable only for use with non-flammable liquids. For flammable see either our G...

Mini Gauge

Mini Gauge

SKU: Mini Gauge

Mini Gauge is an effective yet simple tubular gauge. Its valve less connection ends screw directly into the vessel and commonly used for compressor lube oil tanks or small water tanks or in the case...

Oil Sights

Oil Sights

SKU: Oil Sights

Our Oil Level gauge is a very simple brass and heat proof glass tubular level gauge unit to provide level indication, primarily on oil tanks. As standard they are fitted from the base, but a double b...

CPI Gauge

CPI Gauge

SKU: CPI Gauge

The CPI Tubular Gauge (Chemical and Process Industries) is designed to provide direct level observation of chemicals and solvents.For applications with higher pressure requirements, or where a more r...

Push Button Gauge

Push Button Gauge

SKU: Push Button Gauge

Our basic push button tubular level gauges provide a very simple level monitoring solution. They offer a clear rigid PVC tube, that can be cut to any length to suit your application.The unit is fitte...

Tubular Gauge Glass - Standard

Tubular Gauge Glass - Standard

SKU: Tubular Gauge Glass - Standard

Borosilicate Tubular Gauge Glass John Moncrieff Ltd supplies borosilicate tubular gauge glass designed for accurate, durable liquid level indication in low-pressure environ...

Tubular Gauge Glass - High Pressure

Tubular Gauge Glass - High Pressure

SKU: Tubular Gauge Glass - High Pressure

John Moncrieff — High-Pressure Borosilicate Tubular Gauge Glass At John Moncrieff Ltd, we supply high-pressure borosilicate tubular gauge glass engineered for demanding sigh...

Tubular Gauge Glass - Heavy Wall

Tubular Gauge Glass - Heavy Wall

SKU: Tubular Gauge Glass - Heavy Wall

Extra-Heavy Wall Tubular Gauge Glass John Moncrieff Ltd supplies extra-heavy wall tubular gauge glass engineered to perform under extreme pressure conditions — delivering c...

Tubular Gauge Glass - Red Line

Tubular Gauge Glass - Red Line

SKU: Tubular Gauge Glass - Red Line

Red & White Line Tubular Gauge Glass John Moncrieff Ltd supplies tubular gauge glass with enhanced red and white meniscus lines designed to improve visibility and accur...

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