What are the reasons for the difficulty in starting the asphalt insulation pump

Asphalt insulation pumps are mainly used for pumping, transporting, and spraying high-temperature asphalt (residual oil) liquids. They are suitable for asphalt (residual oil) spraying operations in construction projects such as roads and squares. They can also be used as oil pumps at room temperature to transport non-volatile, low flash point petroleum products such as engine oil, machinery oil, and heavy oil. When the asphalt insulation pump is working, the medium enters the suction chamber and is pressed into the discharge chamber and flows out through the rotation of the gear. Adjusting the handwheel can change the output flow rate. When the handwheel is rotated to the right, the valve is pushed open, and the pump loses output pressure and stops discharging; When the handwheel is rotated to the left, the valve will resume its function and the medium will output normally. Asphalt insulation pump is suitable for conveying media with a temperature of 350 ℃, viscosity not exceeding 40mm2/s, and free of solid particles such as asphalt and paraffin, which have solidification and crystallization properties at room temperature, as well as outdoor installation and insulation requirements in high-altitude areas during the process. Thermal oil, hot water, steam, etc. can be introduced to heat and insulate the conveying medium. The pump body of the asphalt insulation pump is in direct contact with the end caps on both sides of the hard seal. If the flatness of the contact surface does not meet the specified requirements, the pump is prone to inhaling air during operation. Similarly, the end cap of the pump is in direct contact with the cover, and air is also prone to enter. If the cover is made of plastic, it may be damaged or deformed due to temperature changes, which may cause the seal to be loose and enter the air.