Hydraulic double-column exhaust screen changer

Abstract

A hydraulic double-column exhaust type screen changing device, comprising a support seat, a first screen changing column, a second screen changing column, a position switching mechanism for the first screen changing column, and a position switching mechanism for the second screen changing column; There are two column positioning holes. The first screen changing column and the second screen changing column are respectively located in the two column positioning holes. One side of the support seat is provided with a material inlet, and the other side is provided with a material outlet. The two column positioning holes Both are connected to the material inlet, and the positioning holes of the two columns are connected to the material outlet; the first screen changing column is provided with a first material passing hole, and the first filter screen is installed in the first material passing hole, and the second screen changing column There is a second material passage hole on the top, and a second filter screen is installed in the second material passage hole. It is characterized in that: the first screen changing column is also provided with an auxiliary material passage hole. The present invention keeps unimpeded all the time during the whole screen changing process, the pressure fluctuation is small, and there are always enough melt materials passing through the screen changing device, which can avoid the occurrence of fragmentation.

Description

technical field [0001] The invention relates to extrusion molding equipment, in particular to a hydraulic double-column exhaust type screen changing device. Background technique [0002] The function of the screen changing device is to filter the melt material in the flow channel of the extruder to remove impurities in the melt material. [0003] The traditional screen changer is a plate-type screen changer. The plate-type screen changer has a large pressure fluctuation when changing the screen and there will be air bubbles in the mesh, and the plate-type screen changer will be short of material at the moment it starts working. As a result, air bubbles may remain in the product and fragments may occur, resulting in waste products. [0004] The hydraulic double-column exhaust type screen changing device announced by the Chinese utility model manual CN201998409U includes a support base, two screen changing columns and two position switching mechanisms (ie reciprocating motion...

AI Technical Summary

Problems solved by technology

However, during the production process, the screen needs to be changed only when it is detected that the mesh holes on the filter screen are severely blocked (at this time, the pressure sensor can detect that the pressure in front of the filter screen exceeds the preset value). The capacity is very small, so that during the screen changing process, when the first screen changing column is sent to the screen changing position, although the other screen changing column is still in the normal working position, because the filter screen on the material passing hole is Severe blockage, only relying on this feeding hole can only allow a very small amount of melt material to pass through. Therefore, in the process of changing the screen on the first screen changing column, it is easy to break due to too little passing material. As a result, it is necessary to re-thread the film, which consumes a lot of time and affects the normal production

Moreover, when the first screen changing column is sent to the screen changing position, the pressure in front of the filter screen of the other screen changing column increases sharply, and there are large pressure fluctuations, resulting in unstable products produced during the screen changing process (such as uneven thickness of the sheet)

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