1. Overview of the Fully Enclosed Liquefied Petroleum Gas Pump Wuxi Yizhiling Locomotive Development Co. LTD , https://www.yizhilingev.com
With the continuous development of the oil industry, the use of liquefied petroleum gas (LPG) as fuel for urban and rural residents has gradually become more common, replacing traditional fuel sources. As a result, the application of canned LPG systems is on the rise. At the same time, the number of LPG stations has significantly increased. Currently, most canned equipment uses a single-acting vane rotor pump with two single-end mechanical seals on the shaft. One side serves as a shaft seal to prevent LPG leakage, while the other side is a sealed bearing to ensure proper lubrication of the grease. However, in practice, the mechanical seals often suffer from wear and tear, leading to unpleasant odors in the tank area and environmental pollution. Moreover, replacing these seals is a cumbersome process that is not suitable for regular maintenance or overhaul.
Drawing on the principle of permanent magnet drive technology, which has been successfully applied in non-leaking magnetic centrifugal pumps, valves, and reactors, this paper extends the concept to rotor pumps. The result is a fully enclosed liquefied petroleum gas pump that eliminates the need for mechanical seals entirely, achieving complete sealing and absolute safety. In addition to handling LPG, this pump can also transport other volatile liquids such as liquid hydrocarbons, liquid ammonia, and propylene, making it versatile for various applications in the petrochemical industry.
2. Working Principle of the Pump
The fully enclosed LPG pump is a single-acting vane pump, as illustrated in Figure 1. It consists of several key components, including the pump body, inner sleeve, rotor, shaft, sliding vanes, and side plates. The inner sleeve and the rotor are positioned with an eccentric distance e, allowing the vanes to slide within the rotor slots. As the rotor rotates, the vanes are pushed outward by centrifugal force, making contact with the inner surface of the sleeve and forming multiple closed working chambers between the vanes and the end plates.
When the rotor turns counterclockwise, the right-side vanes extend, increasing the volume between adjacent vanes and creating a partial vacuum that draws in the liquid through the inlet. This is the suction phase of the pump. On the left side, the vanes are pushed inward by the inner sleeve, reducing the volume between them and forcing the liquid out through the outlet, completing the discharge process. After one full rotation, the suction and discharge cycle is completed. Between the suction and discharge chambers, there is a sealing zone that isolates the two areas.
The displacement Q of the pump is directly proportional to the eccentricity e and the rotational speed n. By adjusting these parameters, the pump can be customized to meet different operational requirements. Being a rotary positive displacement pump, the flow remains relatively constant at a given speed. With more than four vanes, the pulsation in the displacement is minimal. Additionally, as the pressure difference increases, the displacement decreases slightly, but the viscosity of the fluid has little impact on the efficiency η. These characteristics make it superior to centrifugal pumps in many aspects.
Figure 2 shows the performance curve of the vane pump, and Table 1 lists the basic parameters of the CYQB series of fully enclosed LPG pumps.
Table 1: Basic Parameters of CYQB Fully Enclosed LPG Pumps
Model | Speed (r/min) | Flow (m³/h) | Pressure Difference (MPa) | Working Pressure (MPa) | Motor Power (kW) | Operating Temperature (°C)
CYQB10-5 | 580 | 10 | 0.5 | 1.5 | 4.0 | -40 ~ 100
CYQB15-5 | 790 | 15 | 0.5 | 1.5 | 5.5 | -40 ~ 100
CYQB25-5 | 580 | 25 | 0.5 | 1.5 | 7.5 | -40 ~ 100
CYQB35-5 | 790 | 35 | 0.5 | 1.5 | 11 | -40 ~ 100
CYQB45-5 | 580 | 45 | 0.5 | 1.5 | 11 | -40 ~ 100
CYQB60-5 | 580 | 60 | 0.5 | 1.5 | 15 | -40 ~ 100
3. Transmission and Sealing Principle
Power is transmitted from the gear motor through a flexible coupling to the outer magnetic rotor. The inner wall of the outer magnet rotor is equipped with permanent magnets. The magnetic flux passes through the seal cover to drive the inner magnet rotor, which is aligned on the same axis as the pump rotor. The inner and outer magnetic rotors are alternately arranged with permanent magnets of opposite polarities, enabling repulsion and attraction to maintain precise synchronous rotation. As long as the external torque does not exceed the designed magnetic torque, the inner and outer rotors will not slip.
The seal cover functions similarly to an end cover and is connected via a static seal to the pump body. The pump shaft does not extend outside the casing, ensuring that the fluid is completely enclosed within the pump body and the seal cover. This design eliminates the problem of mechanical seal leakage, replacing it with a static seal, hence the term "non-sealed," "fully enclosed," and "absolutely sealed."
October 04, 2025