Bottom Loading/Unloading Skids

Control and Safety Functions

• Batch Control Function:
  After receiving the loading start command, the batch controller installed on the skid starts the loading process according to the preset program. It opens the relevant valves while collecting flow data from the flow meter. When the preset loading quantity is reached, the controller closes the relevant valves according to the predefined sequence.

• Flow Control Function:
  A flow control valve and a mass flow meter are installed in the loading skid. Parameters such as the safety quantity, safe flow rate, and advance shut-off quantity can be configured to precisely control the loading flow rate. This helps reduce water hammer, improve loading accuracy, and meet process and safety requirements.

• Temperature and Pressure Alarm Function:
  Pressure transmitters and temperature transmitters are installed on the skid pipeline to continuously monitor temperature and pressure during the loading process. When either parameter exceeds the preset limit, the control system triggers an alarm.

• Position Detection Function:
  A loading arm parking stand can be optionally installed on the loading skid. An explosion-proof proximity switch is mounted on the parking stand. After loading is completed, the loading arm must be returned to the parking stand to prevent accidental movement that could damage the loading arm or nearby equipment.

• Grounding Monitoring Function:
  A static grounding monitor is installed on the loading skid to continuously monitor the grounding resistance during loading. If improper grounding is detected, the system generates an alarm and shuts off the loading control valve.

• Lightning Protection Design:
  Surge protection devices are installed on the communication, power supply, and signal lines connected to the loading skid to protect the control system from damage caused by lightning strikes or transient overvoltage.

• Control and Interlocking Function:
  The batch controller controls the automatic valves installed on the skid according to the process requirements. It collects signals from the pressure transmitters, temperature transmitters, flow meter, static grounding system, and valve position indicators. All relevant parameters and statuses are centrally displayed on the batch controller, enabling integrated control and safety interlocking.

• Communication Function:
  The loading skid supports standard RS485/MODBUS or TCP/IP communication protocols. Loading flow, temperature, pressure, valve position, grounding status, and other operating data can be transmitted in real time to the DCS (Distributed Control System). The entire loading process can therefore be monitored by the plant-wide control system, supporting centralized data management and operational monitoring.