Self-locking Hydrocarbons Coupling

● Background

On June 5, 2017, LPG leak occurred during unloading operations at Jinyu Petrochemical in Shandong Province, resulting in a major explosion and fire. The primary cause was an unreliable quick connect coupling.

● Current Situation

Currently, the conventional quick coupling commonly used for liquefied hydrocarbon in the petrochemical industry are made of copper alloy castings and then assembled. The common models are KJB/YJB types, with a centrally spaced design and use O-ring to seal the side of the male coupling on the tanker truck, and equip with locking levers with cam structures on both sides. These couplings often have casting defects, making them prone to cracking during operation. Furthermore, because conventional quick coupling is lack of dry-break (self-sealing) functionality, when disconnected from the tanker truck, a large amount of residual liquid is generated between the ball valves on the drop pipe of loading arm and the tanker-end which are shown in the figure above.

● Legal and Regulatory Requirements

The Ministry of Emergency Management has issued the industry standard "Safety Management Specifications for Liquefied Hydrocarbon Storage Tank Areas in Chemical Enterprises," AQ 3059-2023, requiring the use of this product; the Hebei Provincial Emergency Management Department has also issued a document recommending this product (Hebei Emergency Hazardous Chemical [2023] No. 104).

●Advantages and Features

1. Six-claw and self-locking valve reversing mechanism enables a reliable locking function and prevents accidental detachment due to misoperation of the valve. 

2. When unlocking, the valve will be power-assisted automatically closed by one-step operation, which is highly efficient and has the function of self-sealing when it detaches. 3. It is fully compatible with the existing male coupling on tanker. The spring locking mechanism automatically locks the male coupling without modification. 

4. It has the function of recovering residual liquid, and the rate will be more than 95%. 

5. The flow structure is close to full bore, and the flow and pressure loss are extremely small. 

6. The quick coupling and valve are integrated and can be used as valves. 

7. Modular design, easy replacement of wearing parts, and convenient on-site maintenance. 

8. The connection part is made of ex-proof alloy material, and has obtained the ex-proof certificate issued by the authority.

●Advanced Model

In addition to the standard configuration, this model adds locking status detection and voice prompts. The locking signal can be output to interlock pumps and valves in on-site process pipelines. If the connector is not securely locked, the control panel issues a voice prompt, an indicator light provides a warning, and a signal to the control system to stop the loading. Loading operations can only be resumed when the locking status is correct. The entire detection system utilizes intrinsically safe electrical circuits, and the control panel has an ex-proof rating of EXd IICT6 and an IP65 protection level, fully meeting on-site explosion-proof requirements.