A receiver dryer, as an important component in a refrigeration system, functions to filter impurities in refrigerant, dry refrigerant, and store a certain amount of refrigerant, therefore it is widely used in refrigeration systems, for example, in an automobile air conditioner. Currently, there are many types of receiver dryers for automobile air conditioners, in which the receiver dryer having an upper body and a lower body is widely used.
Reference is made to FIG. 1, which is a schematic view of a relevant receiver dryer.
As shown in FIG. 1, the receiver dryer is of an elongated shape and formed by welding an upper body 1 and a lower body 2 together after the two bodies are butt-jointed. A desiccant bag 11 is accommodated in the upper body 1, and a molecular sieve 111 is received inside the desiccant bag 11. A refrigerant inlet 21 and a refrigerant outlet 27 are defined at a lower end of the lower body 2, and each of an upper end of the refrigerant inlet 21 and an upper end of the refrigerant outlet 27 is provided with a retaining screen 23 made of aluminum. A bottom surface of the retaining screen 23 has a plurality of small holes, and is spot-welded with a concave first metal screen 22. The first metal screen 22 is arranged to face the refrigerant inlet 21. A non-woven fabric filter 25 and a second metal screen 26 are provided between the retaining screen 23 and the refrigerant outlet 27 sequentially. An upper end of the retaining screen 23 is fixed by a protrusion 24, and the protrusion 24 is formed by punching an outside of the lower body 2.
Refrigerant enters via the refrigerant inlet 21, and then flows into the receiver dryer after being filtered by the first metal screen 22. Next, the refrigerant enters the upper body 1, and then passes through the desiccant bag 11 having the molecular sieve 111. The molecular sieve 111 can dry the refrigerant, thereby preventing an ice plug phenomenon from being caused when the refrigerant having excessive water passes through a throttle valve. Then, the refrigerant passes through the small holes on the retaining screen 23, and flows out of the receiver dryer via the refrigerant outlet 27 after being filtered by the non-woven fabric filter 25 and the second metal screen 26, in this way, impurities with certain sizes in the refrigerant are left in the receiver dryer, thereby achieving the predefined function of the receiver dryer.
In the receiver dryer, an effective filter area of the non-woven fabric filter 25 is an area thereof corresponding to the refrigerant outlet 27. In order to ensure a filter precision thereof, the non-woven fabric filter 25 is generally required to have a high compactness. As discovered by the inventor, in a case having the same filter area, the flow resistance of the non-woven fabric filter 25 increases as the compactness thereof increases, which may increase the load of the refrigeration system. On the other hand, since the non-woven fabric filter 25 has a high flow resistant, the impurities in the refrigerant are prone to be deposited on the surface of the non-woven fabric filter 25, which weakens the flow capacity of the non-woven fabric filter 25 and further increases its flow resistant, thereby resulting in a vicious circle and significantly affecting the performance of the refrigeration system.
In view of this, a technical problem to be solved presently by those skilled in the art is to improve the structure of the receiver dryer to reduce the flow resistance thereof while maintaining the filter precision thereof.