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.


Please see below link to our Standard Sizes:


Standard Tank Gauge

Standard Tank Gauge

SKU: Standard Tank Gauge

Our Standard Tubular level gauge is suitable for level monitoring on tanks and similar sealed vessels. The gauges are available in both carbon and stainless steel. Delivery; 1 week or less. They can b...

Quickmount Tank Gauge

Quickmount Tank Gauge

SKU: Quickmount Tank Gauge

Our most popular Tank Level Gauge is designed for general industrial use. The unique isolating valve and collar design, allows for maintenance of the gauge column without tools and the need to drain t...

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

Our borosilicate tubular gauge glass provides accurate and durable level indication in low-pressure environments. Ideal for applications such as tank monitoring, these glasses are engineered to withs...

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

Our extra-heavy wall tubular gauge glass is designed to withstand exceptionally high pressures, reaching up to 600 psi. This robust construction allows for reliable level indication in even the most d...

Tubular Gauge Glass - Red Line

Tubular Gauge Glass - Red Line

SKU: Tubular Gauge Glass - Red Line

Our tubular gauge glass features enhanced red and white meniscus lines for improved visibility and accuracy. These lines are applied using a specialized bonding process that does not require etching,...

Tags: mica shield gauge glass, gauge glass mica shield, sight glass shield, mica disc shield, level gauge mica, protective mica shield, gauge glass accessories, mica shield supplier UK