Key Considerations for Chemical Coupling Applications

Chemical applications demand the highest degree of care and consideration. As such, it’s important for colleagues to understand how safety can be guaranteed when using chemical couplings for the handling, transferral and storage of different products.

Chemical production is one of the world’s largest and most important sectors, with trade volumes above 700 million tons and a worldwide annual sales value of €3,000 billion. The industry is exceptionally diverse and many chemical products require special care to prevent safety hazards such as combustion, impurity and decomposition.

chemical coupling applications todo

Businesses have a legal and moral responsibility to manage the dangers certain chemicals pose to both employees and the environment. However, even if a product has hazardous properties, the risks will be greatly reduced providing it’s managed under controlled conditions. Ultimately, effective handling in accordance with industry regulations is the most important consideration for upholding the reputation of the chemical industry.

Key Chemical Transfer Considerations

There are six key points to consider when using chemical couplings:


The first, and arguably most important, is guaranteeing safety in all product designs. TODO uses high-quality materials and recognized manufacturing practices to protect operators and the environments they work in. The company applies a 5:1 safety factor for all its products and doesn’t accept cheap alternative parts. This maintains performance, even in the most challenging environments.

Industry Experience

Chemical handling and transfer is a key area of focus for TODO. Products benefit from decades of experience in the field and have been appraised regularly to ensure they tackle current industry challenges.


As the Dow and DuPont example below shows, the ability to make modifications is key. Technical adaptations are possible, as well as color coding for bodies of hose and tank units.


TODO’s chemical valves are designed to the most stringent industry regulations, including the Pressure Equipment Directive (PED) certification that requires regular surveillance from our notified body. TODO also has ATEX compliance and certification to AVR/RID, which is the standard for transportation of dangerous goods by road and rail.


TODO works with experienced distribution partners across the global chemical industry. The company also maintains a strong base of knowledge and keeps informed with the latest industry challenges.


TODO supplies a range of safe-handling solutions to suit different customer requirements. From O-ring groove dimensioning to material selection, the company ensures all its designs are fit for purpose by maintaining close contact with key figures across the industry.

Why Engineering Expertise is Key

TODO’s knowledge-based approach is especially important for challenging working environments with exceptional requirements. The company’s work with US companies Dow and DuPont offers a good example. The standard operating temperature range for the TODO-MATIC is -20°C to +80°C (-4°F to +176°F), but Dow and Dupont’s required hose and tank units that could work up to 350°C (662°F). The PTFE grade used for bushings and guides on all standard TODO-MATIC units was unable to meet such high temperature demands. Kalrez 6375 O-rings would also melt under the same conditions, so a bespoke solution was needed.

chemical coupling applications todo

The TODO team worked directly with Dow and Dupont’s application engineers to develop a suitable chemical coupling. This required ongoing testing and reviews using computer simulations, and adoption of proven design principles found in the TODO-MATIC. Both Kalrez 6375 and PTFE were replaced with credible high-grade alternatives, and standard O-ring grooves in the pistons were also adjusted. These changes ensured materials would behave as expected at the extreme pressures and temperatures Dow and DuPont specified.

Testing culminated with the creation of a working prototype in just four weeks with a high chance of success during trials. The product was subsequently proven through physical testing shortly afterward. This is just one example of why engineering expertise is vital for meeting the changing needs of an industry with diverse needs and requirements.

Key Chemical Coupling and Accessory Solutions


The TODO-MATIC is a STANAG 3756 compliant dry-break hose and tank unit solution. A simple push-and-twist connection automatically starts product flow, while the hose unit features an integrated swivel to ensure a high level of flexibility.

There is virtually zero spillage on disconnection, even under pressure. The product is built with high-grade materials, including 316L stainless steel as standard. Aluminum and brass options are also available, as well as special material offerings such as Hastelloy or titanium.

The standard working temperature range is between -20°C to +80°C (-4°F to +176°F), with the ability to go even higher or lower depending on the chosen application. Maximum working pressure is up to 25-bar (363 psi).

This product can be shipped with optional extras, such as a magnetic switch; this indicates when the Hose Unit is fully connected to a standard Tank Unit. A locking mechanism can also be provided to ensure the hose-to-tank connection is locked and secure, avoiding any build-up of hose tension.

To avoid cross contamination by connecting a hose unit to the wrong tank unit, each unit has a number of selective positions, designated by a coded part number according to the coupling size. Color coding is also available to minimize the risk of cross-contamination.

TODO 4WD was developed specially for the use of aggressive chemicals and uses a new patented valve mechanism. Easier to connect / disconnect. Less seal wear due to the use of advanced seating and coating technologies. Less total loss of fluid on disconnection.

NGX BreakAway Coupling

The NGX break-away coupling is a safety product designed to prevent pull-away incidents, where the connection is still intact as a vehicle moves away from a loading/unloading station.

When subjected to excessive force, the NGX’s break pins holding the two symmetrical halves together shear away. This causes the pistons to spring forward and shut off the two severed ends as the break-away coupling simultaneously separates.

todo lpg breakaway coupling

While the break pins can be sized to suit specific applications, 3mm is supplied as a standard as TODO has found this size offers the best stress resistance across the board. However, pin sizes can be adjusted for applications where a weaker or stronger break-away is required.

The NGX has a working pressure of up to 40-bar (580 psi), with a standard working temperature range of -20°C to +80°C (-4°F to +176°F). There is an option to go as low as -45°C (-49°F) if required. The product is also designed to maintain an uninterrupted flow of fluid and gas where possible.

TODO can provide a reset kit to easily achieve full refurbishment of the break-away on site. These kits contain brand new break pins, screws and all of the required O-rings. Operators only have to screw the two halves back together using the bolts provided. As with all products, the NGX is PED-certified and complies with the requirements of ATEX.

Pressure Tight Cap (PTC)

PTCs are PED- and ATEX-compliant stainless-steel caps that contain pressure up to 25-bar (363 psi) and can be fitted to the TODO-MATIC tank unit. Fitting is easy – simply push the cap over the tank unit connection, depressing the lever until the click is felt and then releasing the lever to fully lock the cap in place. From this point the cap will contain any pressure behind it.

PTCs act as a safety device. In the event of line failure, the cap will not only hold the pressure but also provide the operator with a visual warning. A red O-ring is installed on the central valve and will protrude when pressure is present. Operators should investigate the fault before opening the cap if this occurs.

The product may also be used as an official third point of closure when other safety systems are absent. For example, rail applications in Europe will usually lock a rail car in position when loading. This will be safety measure number one, while the second will be a ball valve. From here, the third safety point would be the tank unit. In applications that lack such safety functionality, the PTC can be recognized as the third safety closure.

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