1. Overview of Fully Enclosed Liquefied Petroleum Gas Pumps Wuxi Yizhiling Locomotive Development Co. LTD , https://www.yizhilingev.com
With the continuous advancement of the oil industry, liquefied petroleum gas (LPG) has gradually become a common fuel source for urban and rural residents. As a result, the use of canned LPG has become increasingly widespread, leading to the rapid growth of LPG stations. Currently, most canned equipment uses a single-acting vane rotor pump with two single-end mechanical seals on the shaft. One side is designed to prevent LPG leakage, while the other side ensures proper lubrication of the bearing through a sealed system. However, these mechanical seals often suffer from wear and tear, resulting in noticeable odors in the tank area and environmental pollution. Moreover, replacing the seals is a complicated and time-consuming process, making it unsuitable for regular maintenance. Based 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. A fully enclosed LPG pump is designed to achieve complete sealing without any mechanical seals. This type of pump is not only suitable for LPG but also for transporting volatile liquids such as liquid hydrocarbons, liquid ammonia, and propylene, as well as other similar petroleum products.
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 key components such as the pump body, inner sleeve, rotor, shaft, sliding vanes, and side plates. The inner sleeve and rotor are positioned at 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, maintaining contact with the inner surface of the sleeve. This creates multiple closed working chambers between the vanes and the end plates. When the rotor turns counterclockwise, the right-side vanes expand, creating a partial vacuum that draws in the liquid through the inlet—this is the suction phase. On the left side, the vanes are compressed, reducing the volume and forcing the liquid out through the discharge port—this is the pressure phase. After one full rotation, the suction and discharge cycle is completed. Between the suction and discharge chambers, there is a sealing zone that prevents mixing. The displacement Q is proportional to both the eccentricity e and the rotational speed n, allowing for adjustments in flow rate by varying these parameters. This makes the pump adaptable for various applications.
As a rotary positive displacement pump, the fully enclosed LPG pump delivers a relatively smooth flow, especially when the number of vanes exceeds four, resulting in minimal pulsation. The displacement slightly decreases with increasing pressure difference, but fluid viscosity has little impact on efficiency. These advantages make it superior to centrifugal pumps in certain applications. Figure 2 shows the performance curve of the vane pump, while 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 Differential (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
The 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 field 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, causing them to repel or attract each other, ensuring accurate 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, connected via a static seal to the pump body. Since the pump shaft does not extend outside the casing, the fluid remains completely enclosed within the pump body and the seal cover. This eliminates the problem of mechanical seal leakage, replacing it with a static seal. This design is referred to as a "non-sealed" pump, offering full enclosure and absolute sealing.
October 04, 2025