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DE-112020002423-B4 - Method and apparatus for blowing off and recovering a liquid from the surface of a workpiece using compressed circulating gas

DE112020002423B4DE 112020002423 B4DE112020002423 B4DE 112020002423B4DE-112020002423-B4

Abstract

A device for blowing off and recovering liquid from the surface of a workpiece using compressed circulating gas is characterized in that the device includes a pressure unit (1) for circulating gas; the pressure unit (1) for circulating gas is connected to a blow-off unit via an air duct (2); a feed pipe of a lifting unit (12) for the recovered liquid is connected to an outlet of the blow-off unit; the blow-off unit consists of a compressed air space (3), a blow-off opening (4), a blow-off chamber (5), an air guide plate (6), a gas-liquid separation chamber (7), a filter material (8), an air guide network (9) and an end gas air space (10); the pressure unit (1) for circulating gas comprises a pressurization unit; an air inlet of the pressurization unit is connected to an air outlet of the final gas air space (10), and an air outlet of the pressurization unit is connected to an inlet of the compressed air space (3); an outer wall of the compressed air space (3) and an outer wall of the blow-off unit form the same outer wall; the blow-off chamber (5) is also provided with an air inlet which is connected to the air outlet of the pressurization unit; the inner wall of the compressed air chamber (3) is provided with the discharge opening (4); the circumferential wall of the blow-off chamber (5) and the inner wall of the compressed air space (3) are the same outer wall; the upper opening of the blow-off chamber (5) is an open opening and is used as the inlet and outlet of the workpiece; the bottom of the blow-off chamber (5) is provided with the air guide plate (6); the air guide plate (6) divides a central area of the blow-off unit into a blow-off chamber (5) and a gas-liquid separation chamber (7) upwards and downwards; the air guide plate (6) is provided with guide holes, and the gas-liquid mixture formed enters the gas-liquid separation chamber (7) through the guide holes; the filter material (8) is arranged in the gas-liquid separation chamber (7); the air guide network (9) is arranged around the gas-liquid separation chamber (7); the aperture of the air guide network (9) is smaller than the particle size of the filter material (8); and the annular end gas air space (10) is arranged around the air guide network (9).

Inventors

  • Fangfang BAO
  • Jingwei JIANG
  • Zhenghai JIANG

Assignees

  • ZHEJIANG HAIHE ENVIRONMENTAL TECHNOLOGY CO., LTD.

Dates

Publication Date
20260513
Application Date
20201111
Priority Date
20201010

Claims (10)

  1. A device for blowing off and recovering liquid from the surface of a workpiece using compressed circulating gas is characterized in that the device comprises a pressure unit (1) for circulating gas; the pressure unit (1) for circulating gas is connected to a blow-off unit by an air duct (2); a feed pipe of a lifting unit (12) for the recovered liquid is connected to an outlet of the blow-off unit; the blow-off unit consists of a compressed air space (3), a blow-off opening (4), a blow-off chamber (5), an air guide plate (6), a gas-liquid separation chamber (7), a filter material (8), an air guide mesh (9) and an end gas air space (10); the pressure unit (1) for circulating gas comprises a pressurization unit; an air inlet of the pressurization unit is connected to an air outlet of the final gas air chamber (10), and an air outlet of the pressurization unit is connected to an inlet of the compressed air chamber (3); an outer wall of the compressed air chamber (3) and an outer wall of the blow-off unit form the same outer wall; the blow-off chamber (5) is also provided with an air inlet that is connected to the air outlet of the pressurization unit; the inner wall of the compressed air chamber (3) is provided with the blow-off opening (4); the circumferential wall of the blow-off chamber (5) and the inner wall of the compressed air chamber (3) are the same outer wall; the upper opening of the blow-off chamber (5) is an open opening and is used as the inlet and outlet of the workpiece; the bottom of the blow-off chamber (5) is provided with the air guide plate (6); The air guide plate (6) divides a central area of the blow-off unit into a blow-off chamber (5) and a gas-liquid separation chamber (7) upwards and downwards; the air guide plate (6) is provided with guide holes, and the formed gas-liquid mixture enters the gas-liquid separation chamber (7) through the guide holes; the filter material (8) is arranged in the gas-liquid separation chamber (7); the air guide mesh (9) is arranged around the gas-liquid separation chamber (7); the aperture of the air guide mesh (9) is smaller than the particle size of the filter material (8); and the annular end gas air space (10) is arranged around the air guide mesh (9).
  2. The device according to Claim 1 , wherein the outer wall of the final gas air space (10) and the outer wall of a blow-off tank form the same outer wall and the outer wall of the compressed air space (3) extends to the floor; and the final gas air space (10) and the compressed air space (3) are separated by a partition plate, and the final gas air space (10) is provided with a final gas outlet, and the final gas outlet is connected to the air inlet of the pressurization unit; wherein the outer wall of the final gas air space (10) is provided with a circulation pipe (11) for final gas connected to the pressure unit (1) for circulating gas, and also with a connecting pipe connected to the lifting unit (12) for recovered liquid.
  3. The device according to Claim 1 , wherein the guide holes are evenly spaced on the air guide plate (6); the aperture of the guide hole is 10-50 mm, and the hole spacing is 30-100 mm; and the guide holes are arranged in a rectangular or quincunx shape.
  4. The device according to Claim 1 , wherein the discharge opening (4) is fixed or movable with the workpiece.
  5. The device according to Claim 1 , wherein: if the inner wall of the compressed air space (3) has a polyhedral structure and each blow-off area in the blow-off chamber (5) is less than 1000 cm² , 1-2 fixed air outlets are arranged in the blow-off chamber (5); if each blow-off area in the blow-off chamber (5) is 1000-10000 cm² , 2-30 fixed air outlets or 1-2 movable air outlets are arranged on each side of the blow-off chamber (5); wherein the density of the arranged air outlets corresponds to the density of the polyhedron if the inner wall of the compressed air space (3) has a round structure.
  6. The device according to Claim 1 , wherein the pressurization unit is a fan or a blower or an air compressor.
  7. The device according to Claim 1 , wherein the filter material (8) is a flat filter screen full of square or round holes and with a mesh size of 0.2-8 mm 2 ; or the filter material (8) is a stacked spherical or columnar filter material (8) with a particle size of 2-20 mm.
  8. Method for blowing off and recovering a liquid from the surface of a workpiece using the device according to one of the Claims 1 - 7 , characterized in that it comprises the following steps: pressure unit (1) for circulating gas starts; circulating gas flows through the compressed air space (3) and the air outlet and becomes compressed circulating gas, which is blown onto a workpiece surface in the blow-off chamber (5); finally, the liquid is blown off the surface of the workpiece to be treated to obtain a liquid-gas mixture; the liquid-gas mixture is directed through the air guide plate (6) into the gas-liquid separation chamber (7) for gas-liquid separation; separated end gas enters the air inlet of the pressure unit (1) through the air guide network (9) and the end gas air space (10); the liquid obtained after separation is directed for reuse through the lifting unit (12) for liquid supply.
  9. The procedure according Claim 8 , where the wind speed of the compressed circulating gas for blowing off liquid is 3-30 m/s.
  10. The procedure according Claim 8 , more comprehensively: when the workpiece to be treated is statically blown off, the angle between the direction of a blowing wind and a plane or the tangent plane of the workpiece is 15°-80°, and the wind blows downwards or obliquely downwards; when the workpiece to be treated is dynamically blown off, the angle between the direction of the blowing wind and the plane or the tangent plane of the workpiece is 15°-80°, and the wind blows directly downwards or conversely obliquely downwards.

Description

The invention relates to the technical field of clean production and the avoidance and control of environmental pollution through resource recovery, water saving and emission reduction, in particular a method and a device for blowing off and recovering a liquid from a surface of a workpiece by means of compressed circulating gas. background After surface treatment of the workpiece (e.g., pickling, oxidation, electroplating, electrolysis, electrophoresis, phosphating, etching, etc.), the workpiece is immersed in a chemical solution, causing a liquid layer to form on the workpiece surface due to surface tension. This liquid layer must be removed by a cleaning process. In the surface treatment industry, the cleaning process represents the main source of contamination from pollutants such as heavy metals, cyanide, acids, alkalis, nitrogen, fluorine, phosphorus, and sulfur. At a constant wastewater concentration, the amount of cleaning water used (or the amount of wastewater generated) is in a linear 1:1 ratio to the amount of solution present on the workpiece surface. (1) The method of natural dewatering: Existing methods for reducing the amount of liquid on the surface of the workpiece include the following steps: raising the workpiece above the liquid level of the soaking container, extending the residence time for natural dewatering, or simultaneously applying vibration to the workpiece to cause the liquid to fall back into the soaking container. (2) Dewatering method by air blowing and steam spraying: Simultaneous blowing of clean compressed air and spraying of clean steam to separate and recover the material solution from the workpiece surface. Features of the method: a) To prevent the material solution from drying and crystallizing, which makes subsequent cleaning more difficult, clean compressed gas is used to blow off the workpiece in addition to clean steam. b) The exhaust gas containing the material solution is cleaned and discharged in accordance with the standards. The disadvantages of the natural drainage method are as follows: a) The method cannot remove the liquid adhering to the surface of the workpiece due to surface tension. During prolonged natural drying, the water in the material evaporates naturally, leaving chemical components on the workpiece surface. This leads to crystallization, which makes subsequent washing more difficult. b) In the case of long-term natural dehydration, the workpiece reacts with atmospheric oxygen, forming a layer of reaction products on the surface of the workpiece; for example, atmospheric oxygen reacts with an iron workpiece and forms a yellow layer of iron oxide. The disadvantages of the bubble and spray method for fluid removal are as follows: a) It requires both clean gas and steam to blow the liquid off the workpiece simultaneously, resulting in a complex structure of the blowing system; b) Pure gas and pure steam are difficult to obtain and the costs are high (e.g., for materials that are susceptible to oxidation by air, inert gas must be used as a clean gas); c) The exhaust gas, which contains residual liquid, must be cleaned before discharge to meet the standards, increasing investment and operating costs. While compliance is possible, complete emission-free operation remains unattainable. CN 2 07 091 510 U This concerns a highly efficient pickling machine. The power distribution box consists of a housing containing the descaling bath. CN 2 04 447 609 U discloses a device for removing liquid mist from gas purification systems. Content of the invention To solve the aforementioned technical problems, the invention provides a method and a device for blowing off and recovering surface fluid from workpieces using compressed circulating gas. The device integrates several functions such as blowing off, gas-liquid separation, end gas circulation, and fluid recovery, and is characterized by a simple structure, low operating costs, and a high fluid recovery rate. The invention provides a device for blowing off and recovering liquid from workpiece surfaces using compressed circulating gas. The device comprises a pressure unit for circulating gas; the pressure unit for circulating gas is connected to the blow-off unit by an air duct; a feed pipe of a lifting unit for the recovered liquid is connected to an outlet of the blow-off unit; the blow-off unit consists of a compressed air chamber, a blow-off opening, a blow-off chamber, an air guide plate, a gas-liquid separation chamber, a filter material, an air guide mesh, and a final gas air chamber; the pressure unit for circulating gas comprises a pressurization unit; an air inlet of the pressurization unit is connected to an air outlet of the final gas air chamber, and an air outlet of the pressurization unit is connected to an inlet of the compressed air chamber; an outer wall of the compressed air chamber and an outer wall of the blow-off unit form the same outer wall. The blow-off chamber is also equipped with an a