Dry break couplings

What types of dry disconnect couplings are there?

The most popular types of dry disconnect couplings are:

• DDC couplings, 
• DAC couplings, 
• DGC couplings, 
• DCC couplings.

Below, we describe each of them in detail.

What are DDC couplings?

DDC couplings are couplings that enable the efficient and safe management of the transfer of a wide variety of substances. They are used in situations where rapid connection or disconnection of installation components is necessary without the risk of leakage (even under pressure). The acronym DDC stands for Dry Disconnect Couplings.

What are the applications of DDC couplings?

DDC couplings are particularly used for handling aggressive, hazardous substances, as well as those that may have adverse effects on the environment. They offer versatile applications, covering both loading and unloading (top and bottom), as well as the transfer or distribution of a wide range of products such as

• chemicals, 
• petroleum products, 
• AdBlue®, 
• biofuels, 
• pharmaceuticals, 
• paints, 
• food products,
• hazardous waste.

The practicality of DDC couplings is reflected in their diverse uses, ranging from railway and truck tankers to loading arms, and from collection pipe to IBC tanks.

What is the operating pressure of DDC couplings?

DDC couplings can operate at pressures ranging from 25 bar to 6 bar, which depends on the body material and the size of the coupling. Furthermore, it is possible to connect and disconnect them at pressures of up to 7 bar.

What is the temperature range of DDC couplings?

DDC couplings operate effectively within the temperature range from -20°C and +80°C. However, depending on the seal material, they can even operate at temperatures from -50°C to +200°C.

What certificates do DDC couplings have?

The most important certifications that DDC couplings have are:

• NATO STANAG 3756,
• TÜV TÜ.AGG.304-99, 
• APRAGAZ File ref. 0302/P5832, 
• ADR,
• RID,
• TDT.

DDC couplings have several approvals and certifications that confirm their high quality and safe use. 

What are DAC couplings?

DAC couplings are dedicated couplings for the aviation industry, and are becoming increasingly popular for the safety and efficiency of refuelling operations. They are specifically designed for both civil and military aviation applications. DAC stands for Dry Aviation Couplings.

DAC coupling characteristic feature is a bayonet-type plug with a diameter of 2-1/2 inches, which is characterised by its compatibility with hose ends that comply with international standards such as ISO 45, MS24484, NATO STANAG 3105, as well as British Aerospace 2C14. 

What are the applications of DAC couplings?

DAC couplings are primarily used in the bottom loading processes of tanker trucks and at the main refuelling points in hydrant systems.  It is also important to emphasise that the connector is not designed for refuelling directly under the wing of an aircraft.

What is the operating pressure of DAC couplings?

DAC couplings are characterised by a pressure range of 10 bar, with a safety factor of 5:1. In addition, their test pressure is specified at 15 bar.

What is the temperature range of DAC couplings?

DAC couplings can operate in a temperature range reaching from -20°C to +80°C. It is worth noting, however, that there are additional material options that allow the permissible temperature ranges to be extended.

What certificates do DAC couplings have?

The most important certifications that DAC couplings have are:

• Pressure Equipment Directive (PED) certification, 
• ATEX, 
• ADR (road transport), 
• ISO 45, 
• MS24484, 
• NATO STANAG 3105, 
• British Aerospace 2014.

It is worth noting that DAC couplings have a impressive spectrum of approvals and certifications that allow those couplings work well in the aviation industry. 

What are DGC couplings?

DGC couplings are couplings that are designed to handle liquefied petroleum gas. They have been developed for LPG, i.e. propane, butane and their mixtures.

They are therefore the answer to the growing market needs for efficient and safe handling of these substances. DGC stands for Dry Gas Couplings.

The advantage of DGC couplings is their self-closing design, which significantly simplifies the connection and disconnection processes. This is particularly important in the case of gases, as minimising the risk of leakage is a key aspect of safety.

What are the applications of DGC couplings?

The main applications for DGC couplings include the loading and unloading of road tankers, rail tankers and ships, as well as the refuelling of vehicles. The wide variety of applications highlights their versatility, which is particularly important in the rapidly changing energy sector.

What is the operating pressure of DGC couplings?

DGC couplings can operate with pressures up to 25 bar and have a safety factor of 5:1. In addition, they allow connection at pressures up to 15 bar and disconnection up to 25 bar.

What is the temperature range of DGC couplings?

DGC couplings can operate in the temperature range from -20°C and +80°C, with the LT version available for temperatures as low as -50°C.

What certificates do DGC couplings have?

The most important certifications that DGC couplings have are:

• Pressure Equipment Directive (PED) certification, 
• ATEX EX I12G, 
• ADR (road transport), 
• RID (rail transport), 
• IMDG (maritime transport), 
• TDT, 
• EN 13760 (DN25), 
• EN 13175 (DN 50 and DN 80), 
• TÜV certificate, 
• Lloyd's certificate.

DGC couplings have numerous approvals and certificates confirming their compliance with the highest safety standards.

What are DCC couplings?

DCC couplings are couplings that are designed to handle cryogenic liquids. These specialised devices have been developed to efficiently manage liquid gases at extremely low temperatures (as low as -196°C) following ISO TS 18883. DCC stands for Dry Cryogenic Couplings.

The main advantage of DCC dry cryogenic couplings is the extreme ease and speed of the connection and disconnection process, in which only a small amount of gas is released. This is crucial in terms of maintaining safety and efficiency.

What are the applications of DCC couplings?

DCC couplings are used in a wide range of sectors, including the handling of autocysts, rail tank cars, and ships. They are also indispensable in the refuelling of ships and vehicles using LNG (liquefied natural gas).

What is the operating pressure of DCC couplings?

DCC couplings are available in various sizes, from DN 25 to DN 100, with a maximum operating pressure of 25 bar. In addition, there is a DN 150 version with a maximum PN pressure of 16 bar.

All models have a safety factor of 5:1.

Equally importantly, connection at pressures up to 15 bar and disconnection up to 25 bar is possible.

What is the temperature range of DCC couplings?

The temperature range in which DCC couplings can operate is equally impressive — from -196°C to +85°C. This allows them to be used in a variety of demanding environments.

What certificates do DCC couplings have?

 The most important certifications that DCC couplings have are:

• ATEX, 
• ADR (road transport), 
• RID (rail transport), 
• IMDG (maritime transport), 
• TÜV, 
• Lloyd's Register, 
• TDT.

In addition, they comply with EN 14432. In terms of certifications and approvals, DCC couplings demonstrate compliance with a number of international safety standards.

How do dry disconnect couplings work?

Dry disconnect couplings operate based on the mechanism of piston valves, which are an integral part of both the socket (hose part) and the plug (tank part). These valves open automatically during the connection process of both parts of the coupling and close during disconnection.

This design eliminates the risk of leakage, providing a significant advantage in terms of environmental protection and workplace safety.

One characteristic feature of these couplings is the rotating head of the socket, allowing a 360° rotation. This feature provides great flexibility and facilitates the connection process. The flow of the medium becomes possible only after the proper connection of both parts of the coupling, achieved by rotating the socket head to the right by approximately 100°.

The disconnection process requires a similar rotation but to the left. This movement causes the automatic closure of the valves, ensuring a controlled and safe disconnection of the coupling.

An additional innovative solution that enhances safety is the option of coupling coding. This function prevents accidental connection of the socket with a plug intended for a different medium.

The coding system is based on the proper arrangement of pins and slots in the socket and plug, preventing their incorrect connection. This solution is particularly useful when working with various substances, where confusion of couplings could lead to serious consequences.