At Fox Global, we take pride in delivering engineered solutions that meet the most demanding requirements across Australia’s industrial, infrastructure, and processing sectors. As a family-owned and Australian operated business, our mission is simple: provide high-quality hose, valve, and fitting solutions that customers can trust to perform reliably in the field.
Recently, Fox Global supplied another batch of 100mm (4 inch) Liquid-Filled Pressure Gauges complete with 6-bolt diaphragm seals for use on grout injection lines during major tunnel construction works in Sydney. These instruments are critical for monitoring grout line pressure during ground anchor installations, ensuring precision, safety, and long-term reliability in one of the country’s most challenging environments—underground tunnelling.
In this article, we’ll break down the details of this project, explain the role of diaphragm seals, highlight the features of our gauges, and demonstrate why Fox Global continues to be the trusted name for valves, fittings, and instrumentation solutions in Australia.
The Project: Pressure Monitoring in Sydney Tunnel Works
Tunnelling projects demand absolute accuracy and durability in every component used. Pressure gauges play a key role in controlling grout injection, where cementitious grout is pumped into anchor holes to stabilise and reinforce the surrounding geology.
The Sydney tunnelling project required 100mm liquid-filled gauges paired with diaphragm seals capable of withstanding high pressures while maintaining accuracy in a demanding environment. Fox Global delivered:
- Gauge Specifications:
- 100mm direct mount
- 0–2500 kPa, single scale
- 3/8 BSPP bottom connection
- 304 stainless steel case
- 316 stainless steel connection
- Glycerine-filled for vibration resistance
- Diaphragm Seal Specifications:
- 6-bolt stainless steel diaphragm
- 3/4 BSPT process connection
- Designed for corrosive or contaminated media
Together, this system allowed the tunnelling contractor to monitor grout pressures in real time, ensuring ground anchors were installed correctly and safely.
Why Diaphragm Seals Are Essential
Diaphragm seals—sometimes called chemical seals—are a vital part of modern pressure instrumentation. Their role is to isolate the gauge from direct contact with the process media while still transmitting pressure accurately.
How They Work:
- A thin, flexible stainless steel membrane inside the seal flexes with fluctuations in process pressure.
- This movement is transmitted through a filled liquid to the pressure gauge.
- The gauge can then display accurate readings without coming into direct contact with grout, slurries, or other aggressive materials.
Benefits of Using Diaphragm Seals:
- Media Isolation: Prevents clogging, contamination, and chemical damage to the gauge.
- Extended Lifespan: Protects the delicate internal components of the gauge.
- Improved Accuracy: Ensures stable readings even in slurry-like or viscous materials.
- Versatility: Suitable for corrosive, high-temperature, or contaminated media.
For grout injection in tunnelling, this means gauges last longer, maintenance costs are reduced, and readings remain reliable throughout the project.
The Role of Pressure Gauges in Tunnelling and Grouting
In tunnelling, grout is injected under pressure to fill voids, secure rock formations, and reinforce ground anchors. Accurate pressure monitoring ensures that:
- Grout is correctly delivered – not under-pressurised (leading to weak anchoring) and not over-pressurised (causing fracturing or wasted materials).
- Safety is maintained – preventing blowouts or unplanned grout leaks.
- Performance is verifiable – recorded pressure data proves compliance with engineering and safety requirements.
Without reliable gauges, the integrity of an entire tunnel structure could be compromised. That’s why Fox Global ensures every gauge and diaphragm assembly is calibrated, tested, and certified before dispatch.
Fox Global’s Complete Range of Pressure Gauges
At Fox Global, we stock and supply a comprehensive range of industrial pressure gauges to suit industries from construction and mining through to food processing and pharmaceuticals.
Options Available:
- Gauge Sizes: 40mm, 63mm, 100mm, 160mm face sizes
- Pressure Ranges: Vacuum up to 400 bar
- Mounting Styles: Bottom entry, rear entry, panel mount, and flange mount
- Materials: Stainless steel casing, glycerine-filled for shock resistance
- Specialty Options:
- Diaphragm seals (inline, flanged, or remote capillary types)
- Dual scale gauges (psi/kPa, bar/kPa)
- Oxygen cleaning available for high-purity applications
By keeping a wide selection in stock, we offer same-day dispatch across Sydney and overnight delivery Australia-wide—minimising downtime for our clients.
Fox Global: Supporting Infrastructure and Heavy Industry
Our involvement in the Sydney tunnel construction project is just one example of how Fox Global supports Australia’s infrastructure sector. From major tunnelling works to food processing plants, we deliver tailored solutions that combine availability, technical expertise, and reliability.
Whether it’s custom valve assemblies, specialised hose fittings, or instrumentation like gauges and seals, our team of industry specialists and in-house fabricators can engineer and supply the right solution quickly and efficiently.
Why Choose Fox Global?
- Family-Owned and Australian Operated – Proudly supporting local industries with genuine, reliable service.
- Complete Solutions – Hose, valves, fittings, actuators, gauges, reels, and more—all under one roof.
- In-House Fabrication – Custom assemblies, modifications, and testing available.
- Rapid Dispatch – Same-day Sydney delivery and overnight express across Australia.
- Proven Experience – Trusted by industries including construction, tunnelling, mining, food & beverage, and hydro-excavation.
Contact Fox Global
📞 Phone: 1300 852 795
📧 Email: sales@foxglobal.com.au
🌐 Web: www.foxglobal.com.au
📍 Address: Sydney, NSW, Australia
For all your pressure gauges, diaphragm seals, valves, hose assemblies, and fittings, get in touch with Fox Global today—your trusted Australian-owned partner in industrial solutions.
