This is a very common type of pump used in the chemical industry. Operating on the principle of rotary positive displacement, it can transport a wide variety of media—including high-viscosity fluids and those containing hard suspended particles or fibrous materials. Its broad applicability exceeds that of standard pumps, earning it the nickname "universal pump." Furthermore, this screw pump features a compact structure with few parts, reliable quality, and robust performance, making it a preferred choice for many enterprises and projects. Today, as a manufacturer of G-series screw pumps, Shanghai Shenyin Pump Manufacturing Co., Ltd. would like to explain the characteristics of these pumps and the key considerations for their use.
Characteristics of G-series Screw Pumps
1. Quality: There is a wide variety of G-series screw pumps on the market. Imported models generally feature sound designs and high-quality materials but come with high price tags; service can sometimes be inadequate, spare parts are expensive, and long lead times may disrupt normal production operations. Most domestically produced pumps are imitations of imported models, resulting in inconsistent quality. When selecting a domestic pump and evaluating its cost-performance ratio, it is advisable to choose a model with low rotational speed, a long lead, high-quality drive components, and a long rated service life.
2. Rotational Speed Selection: The flow rate of a G-series screw pump is linearly related to its rotational speed. While high-speed operation can increase flow rate and head, it significantly raises power consumption and accelerates wear between the rotor and stator, inevitably leading to premature pump failure. Additionally, high-speed models often utilize shorter rotor-stator assemblies that are highly susceptible to wear, thereby shortening the pump's overall service life. By using a speed reducer or a continuously variable transmission (CVT) to keep the speed within a reasonable range—below 300 revolutions per minute—the service life can be extended several times compared to high-speed operation. 3. Prevent dry running. G-type screw pumps must never operate without material flow; if this occurs, the rubber stator will burn out almost instantly due to the high temperatures generated by dry friction. Therefore, ensuring the grinder is in good working order and the inlet screen remains unobstructed is essential for the pump's proper operation. To address this, some G-type screw pumps are equipped with a dry-run shutdown device; since these pumps possess self-priming capabilities, a loss of material flow creates a vacuum within the pump chamber, triggering the device to stop the pump.
4. Maintain constant discharge pressure. The G-type screw pump is a positive-displacement rotary pump; if the discharge outlet becomes obstructed, pressure rises progressively, potentially exceeding the preset limit. This causes a sharp increase in motor load and subjects drive components to stresses beyond their design specifications, which—in severe cases—can lead to motor burnout or mechanical failure of the drive parts. To prevent damage, a bypass relief valve is typically installed at the discharge outlet to stabilize pressure and ensure the pump continues to operate normally.
5. Ensure no debris enters the pump body. Solid debris mixed into wet sludge can damage the rubber stator of the G-type screw pump; therefore, preventing debris from entering the pump chamber is crucial. Many wastewater treatment plants install macerators, screens, or filters upstream of the pump to block debris. Screens must be cleaned promptly to prevent clogging.
Precautions for G-type Screw Pumps
1. Check for loose bolts and ensure the power cord and plug are in good condition; the motor insulation resistance should exceed 2 MΩ.
2. To prevent electric shock, appropriate safety measures—such as a residual current circuit breaker (RCCB) or earth leakage protector—must be installed, and reliable grounding must be established.
3. The operating voltage must remain within the range of +5% to -12% of the rated voltage; otherwise, the motor's service life may be shortened, or it may burn out. If the pump is located far from the power source, the power supply cable should be sufficiently thick to prevent voltage drop, which could otherwise prevent operation.
4. Turn on the power switch and let the pump run idle for about 2 minutes to verify normal startup and operation, as well as the correct direction of rotation.
5. Secure the pump body firmly. Connect the inlet and the foot valve using steel piping or rubber hose (ensure the hose is not too soft to avoid collapse under suction). The foot valve must be positioned vertically and at least 30 cm above the bottom to avoid sucking up silt or sand.
6. Before the initial use of the G-type screw pump (including self-priming models), fill the reservoir tank with water. If water does not flow automatically after powering on for a few seconds, check the setup; subsequent uses will not require refilling.
7. Before the initial use of self-priming G-type screw pumps, fill the reservoir tank with water. If water does not flow automatically after powering on for a few seconds, check the setup; subsequent uses will not require refilling.
8. Keep the motor dry during operation and monitor the water level to ensure the foot valve remains submerged. When the ambient temperature drops below 4°C, take anti-freezing measures to prevent the pump body from cracking due to freezing. 9. If the pump is not to be used for an extended period, drain any accumulated water from the pump (for self-priming and automatic pumps, empty the water reservoir); clean the main components thoroughly, apply anti-rust oil, and store the unit in a well-ventilated, dry place for future use.
Characteristics and precautions for the Type G screw pump
We hope this proves helpful to you.