Product Introduction

The LC Roots pump is available in two drive configurations: belt-driven and gear-reducer-driven. This pump features low rotational speed, compact size, high flow rate, low power consumption, self-priming capability, no need for priming oil, and ease of operation. It is widely used for conveying petroleum and petroleum products (with copper impellers available for gasoline) as well as various oils and liquids in industrial settings, such as crude oil, paints, lubricating oils, glass sealants, fatty acids, toothpaste, and mildly alkaline (soap-manufacturing) liquids. In food processing, it can handle a variety of liquids, including soy milk, yeast, and sugar syrup. The pump is also suitable for loading and unloading tanker trucks and oil tankers, offering convenient operation and the ability to run in both forward and reverse directions.

The LCW Roots pump is modified for the conveyance of asphalt and condensate oil by adding an insulation layer to the pump casing exterior or end covers, and employing steam or heat-transfer oil circulation to thermally insulate the pump’s working chamber, thereby enabling both continuous and intermittent operation.

Structural features

This series of pumps consists of a pump casing, pump cover, shaft, gears, rotor, packing, gland, and other components. The pumps are available in two drive configurations: belt drive and gear reducer drive. They can operate in reverse, with oil-resistant skeletal seals installed at both ends of the shaft and an oil-return device in the middle to prevent air ingress or oil leakage.

LC Roots pumps are used in industries such as petroleum, chemical engineering, metallurgy, mining, and power plants for the transfer and pressurization of oil-based media, fuel injection, and the circulation of thin oils in large-scale mechanical equipment; they can also serve as lubrication pumps in various types of machinery.

The key component of an LC Roots pump is the rotor, and the rotor’s performance hinges on its profile. Commonly used rotor profiles include circular-arc, involute, and cycloidal types. In recent years, the “circular-arc → involute → cycloid” rotor profile proposed by Northeastern University has been widely adopted because it reduces gas drag, enhances pump performance at low pressures, and improves pumping efficiency. It is anticipated that new and improved rotor profiles for Roots pumps will continue to emerge, further elevating their operational performance. The outer contour of the rotor’s cross-section defines the rotor’s profile.

Motor overheating is a common issue encountered during the operation of Roots pumps; the detailed analysis and inspection are as follows:

1. Scope of application (flow rate and head): When selecting a gear oil pump, the appropriate motor shall be chosen according to the series-specific performance curve.

2. The medium-specific gravity gear oil pump is equipped with a motor suitable for large-scale gear oil pumps;

3. If the packing gland is tightened too much or the mechanical seal spring is adjusted too tightly, readjust the compression of the packing gland or the mechanical seal spring.

4. Poor installation quality of the Roots pump, including interference at mating surfaces or misalignment between the motor and the pump shaft—inspect the installation quality and eliminate any installation defects. For the above-mentioned conditions, conduct a systematic analysis to identify the root cause of motor overheating, and then carry out appropriate repairs and remedial measures based on the specific fault.

Technical specifications of the LC Roots pump