1、 Overview

In 1588, Ramelli proposed the concept of a multi element slider device and created the world's first Ramelli pump. From an institutional perspective, it is undoubtedly highly reasonable to use pistons for rotational motion instead of pistons for reciprocating motion to achieve gas compression. However, it is impossible to form a working chamber with periodic volume changes using only the rotor and cylinder body components, and auxiliary components must be added. If several blades (referred to as sliding blades) that can slide freely in slots opened on the rotor or cylinder body are added, a uniform speed rotary compressor, also known as a rotary compressor, is formed.








（1） Single working chamber sliding vane compressor




1. The structure of a single working chamber sliding vane compressor is the traditional structural form of a sliding vane compressor. The right figure is a cross-sectional view of a single working chamber slide, which is mainly composed of three parts: the body (also known as the cylinder), the rotor, and the slide. The outer surface of the rotor and the inner surface of the cylinder are both circular, and the rotor is eccentrically installed inside the cylinder, making them geometrically tangent (in actual structures, a certain gap is maintained at the tangent point), forming a crescent shaped space between the inner wall of the cylinder and the outer surface of the rotor. There are several longitudinal grooves (sliding plate grooves) on the rotor, and each groove is equipped with a sliding plate that can move freely in the radial direction. When the rotor rotates, the sliding plate is thrown out of the groove by centrifugal force, and its end is tightly attached to the inner surface of the cylinder, dividing the crescent shaped space into several fan-shaped small chambers, which are called the elements. With the continuous rotation of the rotor, the volume of the elements changes from small to large in a cyclic manner.

2. Compared with other compressors, slide compressors have the following advantages:
1) Simple structure, few components, easy processing and assembly, and convenient maintenance.
2) Smooth operation, low noise, and minimal vibration.
3) The starting impact is small.
4) High efficiency.
5) Compact structure, small size, light weight, easy to install in narrow spaces, making it more suitable for use in automotive air conditioning.
6) Multiple elements in the compressor work simultaneously, resulting in a relatively large gas transmission volume, uniform flow rate, low pulsation, and no need to install large gas reservoirs.
7) When the top of the slide and the inner surface of the cylinder wear out, the slide can automatically elongate to compensate, thereby extending its service life.

3. According to the different lubrication methods between the slide, rotor, and cylinder (which mainly depend on the slide material), slide compressors can be divided into three categories: drip oil, spray oil, and oil-free.

（2） Dual working chamber sliding vane compressor

1. Working principle: The dual working chamber sliding vane compressor is a new type of rotary compressor developed and used in the 1970s. The sectional view of the dual working chamber sliding vane compressor is shown on the right, which consists of a cylinder, rotor, sliding vanes, end caps, inlet and outlet holes, and exhaust valves. Circular rotor 2 is installed concentric inside flat circular cylinder 3, forming two crescent shaped working chambers. There are several slots on the rotor, and slide plate 4 is placed in them and can slide back and forth. When the prime mover drives the rotor to rotate, due to the centrifugal force, the slide plate is thrown out and tightly adheres to the inner surface of the cylinder, forming the working element of the compressor. Each element completes two working processes during one rotation of the rotor.





2. In addition to the characteristics of a single working chamber sliding vane compressor, a dual working chamber sliding vane compressor also has the following features:
1) Each element absorbs and exhausts twice during each rotation of the rotor, completing two working cycles, resulting in a more uniform flow rate, less pulsation, larger gas transmission capacity, and a more compact structure.
2) The compressor has two symmetrical working chambers, with two sets of suction and exhaust ports 180 degrees apart^o
3) The rotor and cylinder are concentric, which brings great convenience to the manufacturing and installation of the machine.

3. The dual working chamber sliding vane compressor is mainly used in small gas compression devices and automotive air conditioning systems. The capacity range of the dual working chamber sliding vane compressor for automotive air conditioning is 80~140cm3/r. In addition, it is also used in air cooling and air conditioning systems such as engine rooms, military vehicles, and civilian residences.

（3） Through slide compressor

The working principle, as shown in the diagram on the right, is a schematic diagram of the structure of the through slide compressor. The sliding groove on the rotor is continuous, and the entire sliding plate is placed in the through groove. The two ends of the slider are in contact with the cylinder. When the rotor rotates, it drives the slider to move, and its two ends always slide along the inner wall of the cylinder. Due to the constant constraint of the cylinder inner wall on the movement of the slide, the cylinder profile is no longer a circle or ellipse, but a curve (surface) generated based on the mechanism of slide movement.








2. In addition to the characteristics of traditional vane compressors, the characteristic of the vane compressor is that its vane end is sealed by being constrained by the inner wall of the cylinder, and there is a complete or partial oil film between them. Therefore, it not only ensures the sealing of the vane end but also greatly reduces the friction loss in this part. This is the biggest advantage of the through slide compressor.
3. The purpose of the through slide compressor is mainly used in room air conditioning and car air conditioning systems. In addition, the through slide mechanism is also used as a vacuum pump, generating a rough vacuum of about 600Pa with a capacity range of 2000~6000cm3/r.

2、 Typical structural examples for refrigeration
（1） Sliding vane compressor for automotive air conditioning
（2） Rotary vane vacuum pump

Rotary vane vacuum pump, abbreviated as rotary vane pump. It is an oil sealed mechanical vacuum pump. Its working pressure range is 101325~1.33 × 10-2pa, belonging to low vacuum pumps.




Working principle of single-stage rotary blade

The left figure is the structural diagram of the 2X rotary vane pump, which has the same basic structure as the single working chamber sliding vane compressor. The spiral groove on the rotor is connected through the center of the rotor, and two spiral blades with springs on the back are installed in it. When the rotor rotates, the top of the spiral blades is kept in contact with the inner wall of the pump chamber by centrifugal force and spring force. An oil tank is installed above the pump body to seal the exhaust valve with oil. The gas discharged through the valve passes through the oil layer in the tank and is released into the atmosphere. The pump is a two-stage pump, with the high vacuum stage and low vacuum stage connected through an air duct. There is an auxiliary exhaust valve on the airway. When the exhaust pressure of the * stage is higher than atmospheric pressure, the auxiliary exhaust valve is pushed open to exhaust, so that the pressure in the channel is never higher than atmospheric pressure.
A rotary vane pump can remove dry gases from sealed containers, and if equipped with a gas ballast device, it can remove a certain amount of condensable gases. Qi Zhen, also known as gas mixing, is an effective method to prevent steam condensation and avoid oil pollution. It involves introducing a controlled airflow (usually room temperature, dry air) through a gas damper hole into a compressed chamber, mixing with the extracted steam to form a mixture of steam and air. This ensures that when the mixture is compressed to exhaust pressure, the steam does not condense, allowing the steam to be discharged outside the pump along with the air.