Explanation of the Negative Pressure Ambulance System Design

Principle of the Negative Pressure Ambulance System

The negative pressure ambulance system consists of a casing, filtration system, disinfection system, exhaust system, and control system. It ensures that the air pressure inside the vehicle is lower than the outside atmospheric pressure, allowing air to flow freely from outside to inside the vehicle. The air inside the vehicle is treated to neutralize harmful substances before being expelled, creating a fixed airflow field in the negative pressure cabin. Air flows from the clean zone (medical personnel area) to the infection source zone (patient area). 

Simultaneously, the airflow control within the vehicle ensures that clean air enters from above and is expelled from below, keeping the air around the medical staff's head clean and sterile, while the air around the patient is polluted and then expelled through the exhaust and filtration system. The expelled air is filtered to be clean and sterile. This design reduces the risk of cross-infection between medical personnel and patients and prevents wider infection among the population, achieving true "safe isolation".

Design of the Filtration System in the Negative Pressure Ambulance System

The filtration system is used to filter contaminated air containing viruses. Viruses primarily spread in the air through droplets and droplet nuclei, which require efficient air filters for removal. The negative pressure ambulance system uses high-efficiency filter disinfectors to prevent the leakage of polluted air from the medical cabin.

Design of the Disinfection System in the Negative Pressure Ambulance System

The design of the disinfection system can refer to air disinfectors. Common air disinfection methods include ultraviolet disinfection, ozone disinfection, and plasma disinfection. Since the negative pressure system in ambulances is mainly designed to expel the exhalations of infected patients, the installation position is often close to the patient's head. Ozone disinfection is unsuitable as ozone can directly damage alveolar epithelial cells and irritate respiratory mucosa, making inhalation of ozone into the lungs strictly prohibited. Therefore, ultraviolet disinfection is more suitable for the negative pressure ambulance system.

Design of the Exhaust System in the Negative Pressure Ambulance System

The negative pressure cabin must accommodate a negative pressure isolation stretcher, medical cabinets, and specialized medical equipment, making it very compact in structure and space. The negative pressure ambulance system is best designed using a negative pressure unidirectional flow, i.e., forced exhaust and natural intake, using the pressure difference between the inside and outside to ventilate. This design features simplicity, ease of operation, and does not take up space inside the cabin.

Design of the Control System in the Negative Pressure Ambulance System

The control of the ambulance negative pressure purification and disinfection system primarily involves system startup and shutdown, pressure difference adjustment, and pressure difference over-limit alarm. Variations among different manufacturers, vehicle models, and processors result in differences in the sealing performance of each negative pressure ambulance. Therefore, the negative pressure system must be adaptable, universal, and adjustable.