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

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).

Description

[0001] 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

[0002] 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.

[0003] 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.

[0004] 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 with the regulations is possible, complete emission-free operation remains unattainable. CN 2 07 091 510 U relates to a high-efficiency pickling machine. The electrical 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 cleaning systems. Content of the invention

[0005] 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.

[0006] 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 via 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 provided with an air inlet that is connected to the air outlet of the pressurization unit; an inner wall of the compressed air chamber is provided with a blow-off opening; a circumferential wall of the blow-off chamber and an inner wall of the compressed air chamber form the same outer wall; an upper opening of the blow-off chamber is used as an inlet and outlet for the workpiece; a bottom of the blow-off chamber is provided with an air guide plate; the air guide plate vertically divides the central area of ​​the blow-off unit into a blow-off chamber and a gas-liquid separation chamber; the air guide plate is provided with guide holes, the gas-liquid mixture entering the gas-liquid separation chamber through the guide holes; the filter material is arranged in the gas-liquid separation chamber;An air guide mesh is arranged around the gas-liquid separation chamber; the aperture of the air guide mesh is smaller than the particle size of the filter material; an annular end gas air space is arranged around the air guide mesh.

[0007] Preferably, the outer wall of the final gas air space and the outer wall of the blow-off chamber form the same outer wall, which is the downward extension of the outer wall of the compressed air space; the final gas air space and the compressed air space are separated from each other by a partition plate, and the final gas air space is provided with a final gas outlet, which is connected to the air inlet of the pressurization unit; the outer wall of the final gas air space is equipped with a circulation pipe for final gas, which is connected to the pressure unit for circulation gas, and with a connecting pipe that is connected to the lifting unit for recovered liquid.

[0008] Preferably, the guide holes are evenly distributed on the air guide plate; the diameter of the guide holes is 10-50 mm, and the hole spacing is 30-100 mm; the guide holes are arranged in a rectangular or quincunx shape.

[0009] Preferably, the position of the discharge opening is fixed, or it can move with the workpiece. If the discharge opening is fixed and if the distance between the discharge opening and the workpiece is large, an additional extension tube can be attached to the discharge opening.

[0010] Preferably, if the inner wall of the compressed air space has a polyhedral structure, each blow-off area in the blow-off chamber is smaller than 1000 cm². 2 Alternatively, mobile air outlets can be installed, with one or two air outlets arranged on each side of the blow-off chamber. If each blow-off area in the blow-off chamber is 1000–10000 cm² 2If the chamber is large, 2-30 fixed air outlets are arranged in the blow-off chamber, or 1 to 2 movable air outlets are arranged on each side of the blow-off chamber. If the inner wall of the compressed air chamber has a circular structure, the density of the arranged air outlets corresponds to the density of the polyhedron.

[0011] Preferably, the pressurization unit comprises a fan, a blower, or an air compressor. Preferably, the filter material is a flat filter screen with square or round holes and a mesh size of 0.2–8 mm. 2 ; or the filter material is a stacked spherical or columnar filter material with a particle size of 2-20 mm.

[0012] The invention relates to a method for blowing off and recovering liquids from the surface of a workpiece using the aforementioned device, wherein the method comprises the following steps: activating the circulating gas pressure unit; the circulating gas flows through the compressed air chamber and the air outlet, and then a compressed circulating gas is blown onto the workpiece surface in the blow-off chamber, finally blowing off the liquid on the surface of the workpiece to be treated, thereby creating a liquid-gas mixture. The liquid-gas mixture is directed through the air guide plate into the gas-liquid separation chamber for gas-liquid separation. The separated gas enters the air inlet of the pressure unit and the gas air chamber through the air guide mesh; the liquid obtained after separation is directed for reuse by the lifting unit for liquid supply.

[0013] Preferably, the wind speed of the compressed circulating gas for blowing off the liquid is 3-30 m / s.

[0014] Preferably, when the workpiece to be treated is statically blown off, the angle between the direction of the blowing wind and the plane (or tangent plane) of the workpiece is 15°–80°, with the wind blowing 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 tangent plane) of the workpiece is 15°–80°, and the wind blows directly downwards or obliquely downwards.

[0015] The invention relates to a device for blowing off and recovering liquids from the surface of a workpiece using compressed circulating gas, wherein the device comprises: a pressure unit for circulating gas, a blow-off unit connected to the pressure unit for circulating gas via an air duct, and a lifting unit for the recovered liquid, which is connected to the blow-off unit via a feed pipe. The blow-off unit comprises 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; wherein the pressure unit for circulating gas comprises a pressurization unit, and the air inlet of the pressurization unit is connected to the air outlet of the final gas air chamber, and the air outlet of the pressurization unit is connected to the inlet of the compressed air chamber.The outer wall of the compressed air chamber and the outer wall of the blow-off unit form the same outer wall; the blow-off chamber 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 is provided with a blow-off opening; the circumferential wall of the blow-off chamber and the inner wall of the compressed gas air chamber form the same outer wall; the upper opening of the blow-off chamber is an open opening and is used as the inlet and outlet of the workpiece; the bottom of the blow-off chamber is provided with an air guide plate; the air guide plate divides the central area of ​​the blow-off unit vertically into a blow-off chamber and a gas-liquid separation chamber; the air guide plate is provided with guide holes, whereby the gas-liquid mixture enters the gas-liquid separation chamber through the guide holes; a filter material is arranged in the gas-liquid separation chamber;An air guide mesh is arranged around the gas-liquid separation chamber; the aperture of the air guide mesh is smaller than the particle size of the filter material; an annular end gas air space is arranged around the air guide mesh. Compared to conventional short-term blow-off of workpieces, this device reduces chemical consumption by 10-20%, while simultaneously reducing the amount of chemical fluid carried into the cleaning process by workpieces by 40-70%. If this portion of the chemical fluid is fully recovered, wastewater emissions and wastewater treatment costs in the surface treatment industry can each be reduced by approximately 50%. This has a positive impact on resource recovery, pollutant emission control, water conservation, and significantly improves clean production and environmental protection in the surface treatment industry. The device described in this application requires only the blowing of recycled exhaust gas with low moisture content onto the workpieces, thereby eliminating the need for spraying and saving costs for spraying equipment and its operation. The pressurized gas recirculation unit in this application utilizes circulating, low-humidity gas recovered from the stripping gas after gas-liquid separation. This eliminates the need for a continuous supply of clean gas and thus reduces clean gas costs (particularly important for stripping solutions prone to reacting with air, where inert gases should be used as the clean gas source). The device presented here eliminates the need for the exhaust gas capture and purification processes associated with air-spray stripping. Description of the drawings

[0016] Fig.Figure 1 is a schematic representation of the device according to the invention for blowing off and recovering a liquid from a surface of a workpiece by means of compressed circulating gas, wherein 1 is the pressure unit for circulating gas, 2 is the air duct, 3 is the compressed air chamber, 4 is the blow-off opening, 5 is the blow-off chamber, 6 is the air guide plate, 7 is the gas-liquid separation chamber, 8 is the filter material, 9 is the air guide mesh, 10 is the final gas air chamber, 11 is the circulation tube for final gas and 12 is the lifting unit for the recovered liquid. Specific implementation

[0017] The invention relates to a device for blowing off and recovering liquid from a surface of a workpiece by means of compressed circulating gas, wherein the device comprises: a pressure unit 1 for circulating gas, a blow-off unit connected to the pressure unit 1 for circulating gas by an air channel 2 and a lifting unit 12 for the recovered liquid, which is connected to the blow-off unit by the supply pipe.

[0018] The blow-off unit comprises a compressed air chamber 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 chamber 10.

[0019] The pressure unit 1 for circulating gas comprises a pressurization unit; the air inlet of the pressurization unit is connected to the air outlet of the final gas air space 10, and the air outlet of the pressurization unit is connected to the inlet of the compressed air space 3.

[0020] The outer wall of the compressed air chamber 3 and the outer wall of the blow-off unit form the same outer wall; the blow-off chamber 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 a blow-off opening 4.

[0021] The circumferential wall of the blow-off chamber and the inner wall of the compressed air chamber 3 form the same outer wall; the upper opening of the blow-off chamber is an open opening and is used as an inlet and outlet for the workpiece.

[0022] The bottom of the blow-off chamber 5 is provided with an air guide plate 6; the air guide plate 6 divides the central area of ​​the blow-off unit vertically into a blow-off chamber 5 and a gas-liquid separation chamber 7; 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.

[0023] A filter material 8 is arranged in the gas-liquid separation chamber 7; an 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; an annular end gas air space 10 is arranged around the air guide mesh 9.

[0024] The device for blowing off and recovering liquid from a surface of a workpiece by means of compressed circulating gas in the invention comprises a pressure unit 1 for circulating gas; the pressure unit 1 for circulating gas comprises a compressor; the air inlet of the compressor is connected to the air outlet of the final gas air chamber 10, and the air outlet of the compressor is connected to the inlet of the compressed air chamber 3;

[0025] In the invention, the circulating end gas is pressurized by a fan, blower, or air compressor so that the pressurized circulating gas has a high wind pressure, high wind speed, and a large volume of air at the circulating gas outlet 4. For most workpieces and materials, air can be used as the circulating gas; however, for blowing off and recovering chemical materials and workpieces that are prone to oxidation or react with air components, or when the workpiece exposed to air is susceptible to redox reactions with atmospheric constituents, nitrogen or other inert gases can be used as a substitute for air. Examples include high-grade iron workpieces and strongly reducing materials.

[0026] The device comprises a blow-off unit connected via air duct 2 to the pressure unit 1 for circulating gas. The blow-off unit includes a compressed air chamber 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, an end gas air chamber 10, and a circulation pipe 11 for the end gas. The pressure unit 1 for circulating gas is connected via air duct 2 to the air inlet of the compressed air chamber 3 and the air outlet of the end gas air chamber 10.

[0027] The device in the invention comprises a compressed air chamber 3 in a blow-off unit, which is connected to the pressure unit 1 for circulating gas via the air duct 2. Circulating gas is directed into the compressed air chamber 3 via the air duct 2; the compressed air chamber 3 is arranged around the circumference of the blow-off chamber 5. The outer side wall of the compressed air chamber 3 and the outer wall of the blow-off unit form the same outer wall, with the upper wall being the cover of the blow-off unit. The lower wall and the upper wall of the end gas air chamber 10 form the same wall, the height being equal to the height of the air guide plate 6.Each side of the inner wall of the compressed air chamber 3 is provided with one or more blow-off openings 4; if the distance between the air outlet and the workpiece is too great, air outlet feedthrough tubes should be provided; the outer wall of the compressed air chamber 3 and the outer wall of the blow-off groove form the same outer wall; a blow-off area is located inside the blow-off opening 4. The bottom of the blow-off chamber 5 is provided with an air guide plate 6; the air guide plate 6 vertically divides the central area of ​​the blow-off unit into a blow-off chamber 5 and a gas-liquid separation chamber 7; the air guide plate 6 is provided with guide holes, the gas-liquid mixture formed entering the gas-liquid separation chamber 7 through the guide holes.The compressed air chamber 3 in the blow-off unit promotes the formation of a basic isobaric zone within the air space. One or more blow-off openings 4 are arranged at various positions within the compressed air chamber 3 to blow off the liquid from the workpiece. The compressed air chamber 3 has a large flow area, and the air pressure is essentially free of pipe resistance and pipe losses. The compressed gas blown out of the blow-off opening 4 must meet the requirements for moisture (liquid content), air pressure, and air volume. The compressed air chamber 3 is an annular, box-shaped, or closed cavity with one air inlet and more than two air outlets. To reduce air resistance, the air inlet angle within the cavity is tangential to the blow-off chamber 5 if the blow-off unit is circular; if the blow-off unit is square, the air inlet angle within the cavity is tangential to the central corner.The corner of the compressed air chamber 3 is preferably designed as an arc-shaped corner. The width of the compressed air chamber 3 varies depending on the properties of the workpiece and the liquid and is preferably 60-400 mm.

[0028] The discharge opening 4 is equipped with a regulator for air volume and wind direction. This regulator adjusts the air volume and wind direction of the discharge opening 4 according to the size, shape, and position of the workpiece to achieve the most suitable air volume and wind direction. If the distance between the air outlet and the workpiece is too great, the discharge pipe of the discharge opening 4 should be positioned so that the discharge opening 4 is at the optimal distance from the workpiece to achieve the best blow-off effect. The discharge opening 4 can be fixed or movable relative to the workpiece. The wind force generated by the pressurized gas expelled from the discharge opening 4 is greater than the surface tension of the liquid on the workpiece surface. This force breaks down the tension structure on the liquid's surface, allowing the liquid to separate from the workpiece and enter the gas-liquid separation chamber 7 along with the pressurized gas.If the inner wall of the compressed air space 3 has a polyhedral structure and each blow-off surface in the blow-off chamber 5 is less than 1000 cm². 2 If the area is large, preferably 1 to 2 fixed air outlets are arranged in the blow-off chamber 5, and if each blow-off area in the blow-off chamber 5 is 1000 - 10000 cm² 2If the workpiece is large, preferably 2 to 30 fixed air outlets are arranged in the blow-off chamber 5, or preferably 1 to 2 movable air outlets are arranged; if the inner wall of the compressed air space 3 is round, the density of the arranged air outlets corresponds to the density of the polyhedron. The wind direction of the blow-off opening 4 is as follows: when the workpiece to be treated is blown off statically, the angle between the direction of the blowing wind and the plane (or the tangential plane) of the workpiece is 15°–80°, with the wind blowing downwards or obliquely downwards; when the workpiece to be treated is blown off dynamically, the angle between the direction of the blowing wind and the plane (or the tangential plane) of the workpiece is 15°–80°, and the wind blows directly downwards or obliquely downwards. The wind speed of the pressurized gas blown out of the vent 4 reaches 20-60 m / s on the surface of the workpiece.The blowout opening 4 is preferably provided with a switch for adjusting the air volume and a device for adjusting the wind direction; depending on the characteristics of the workpiece, some blowout openings 4 can be selectively opened; the actual number, the wind direction and the air volume of the blowout openings 4 can be switched and adjusted according to the properties of the workpiece and the liquid.

[0029] In the invention, the blow-off chamber 5 is located in the central region of the blow-off container, the compressed air space 3 is arranged on the outside of the blow-off chamber 5, and the air guide plate 6 of the blow-off chamber 5 is arranged at the bottom of the blow-off chamber 5. The air guide plate 6 is provided with guide holes, the guide holes being 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; the guide holes are arranged in a rectangular or quincunx pattern.

[0030] The air guide plate 6 and the base plate of the compressed air chamber 3 can be arranged on the same plate, with the base plate of the compressed air chamber 3 having no hole. After the liquid on the workpiece is blown off by the compressed gas, a liquid-gas mixture is formed. The blown-off large liquid droplets fall directly onto the air guide plate 6 and then move along the guide holes on the air guide plate 6 into the gas-liquid separation chamber 7. The liquid-gas mixture flows through the uniformly spaced guide holes on the air guide plate 6 to form a uniform airflow and enter the gas-liquid separation chamber 7.

[0031] According to the invention, a filter material 8 is located in the gas-liquid separation chamber 7, and an 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. An annular end gas air space 10 is arranged around the air guide mesh. The gas-liquid separation chamber 7 is located below the air guide plate 6 in the central area of ​​the blow-off unit. After the gas-liquid mixture generated by the blow-off chamber 5 enters the gas-liquid separation chamber 7, the gas-liquid mixture impacts the filter screen or filter material 8. This causes the small liquid droplets to combine into larger liquid droplets, which then fall into the cavities of the filter material at the bottom of the gas-liquid separation chamber 7.Large liquid droplets blown off the workpiece drip directly onto the guide plate, then drip along the guide holes into the gas-liquid separation chamber 7. Subsequently, they flow through the cavities of the filter screen or filter material 8 and collect in the cavities of the filler at the bottom of the gas-liquid separation chamber 7. The exhaust gas of the gas-liquid mixture, obtained through gas-liquid separation, is discharged through the mesh of the air guide net 9 into the exhaust gas air space 10. The filter material 8 is made of plastic, ceramic, enamel, quartz sand, and other inert materials and is either a mesh-like filter material made of the inert material or a granular filter material with a high specific surface area. The filter material is a large-surface-area filter screen made of the aforementioned materials, with mesh openings of 0.2–8 mm. 2Alternatively, the filter material is a stacked spherical or columnar filter material with a particle size of 2-20 mm. The mesh-like filter material refers to a filter screen with square or round holes and a mesh size of 0.2-8 mm. 2The filter screen is preferably provided with 2-3 layers and is installed horizontally above the outlet of the recovered liquid in the gas-liquid separation chamber 7. The filter screen is removable and washable. The granular filter material with a high specific surface area is a spherical or columnar filter material with a particle size of 2-20 mm, which is stacked in a gas-liquid separation chamber 7. The air guide mesh 9 serves to prevent the filter material 8 from flowing out of 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 aperture of the air guide mesh 9 is preferably 1.5-10 mm. After stripping, the fluidized gas-liquid mixture, separated from the workpiece, flows over the surface of the filter material 8.Fine liquid droplets collide upon impact with the mesh or filter material 8 and combine to form larger droplets. These droplets then fall through the mesh or filter material 8 into a liquid pool at the bottom of the gas-liquid separation chamber 7 or into the spaces between the filter material 8, forming a liquid layer. The final gas, which has released most of the liquid, flows through the mesh or spaces of the granular filter medium in the upper part of the gas-liquid separation chamber 7 to the air guide mesh 9. It then flows through the mesh openings into the final gas chamber 10, forming a final gas layer in its upper part.

[0032] The device according to the invention comprises a final gas air chamber 10, which is arranged below the base plate of the compressed air chamber 3 and around the outer surface of the air guide network 9. The final gas chamber serves as a collection chamber for final gases after gas-liquid separation and forms an annular, closed cavity. The air inlet side of the end gas air space 10 is a porous air guide mesh 9 inside the air space, with the air outlet of the air space located at the position corresponding to the compressor fan (or ventilator or air compressor) on the outer wall of the air space. The end gas air space 10 is a low-wind-resistance air space, and its outer wall is equipped with a circulation pipe 11 for end gas, which is connected to the pressure unit 1 for circulation gas, and with a connecting pipe that is connected to a lifting unit 12 for the recovered liquid. The end gas enters the pressure unit 1 for circulation gas from the circulation pipe 11 through the outlet of the end gas air space 10 for recycling, so that no end gas is released into the workshop or the external environment and no secondary pollution occurs.Some undetached fine droplets in the final gas continue to enter pressure unit 1 and are reused as circulation air. The final gas is characterized by the presence of some undetached fine liquid droplets in the gas phase, with the final gas exhibiting low humidity and a liquid concentration of 15-50 g / m³ after gas-liquid separation. 3 The circulating end gas continues to enter the pressure unit 1 for circulation gas to be used as circulation air. The bottom of the end gas air chamber 10 is provided with a liquid outlet, and the vented recovered liquid is drained through this outlet. The device according to the invention also includes a lifting unit 12 for the recovered liquid connected to the blow-off unit; wherein the lifting pump for the recovered liquid in the lifting unit 12 is a chemically corrosion-resistant pump made of plastic, ceramic, or other materials. The supply line of the lifting unit 12 for the recovered liquid is connected to the outlet opening on the lower part of the blow-off unit by a connecting pipe; in particular, the end gas air space is provided with an outlet opening, and the lifting unit 12 for the recovered liquid is connected to the outlet opening by a connecting pipe. The lifting unit 12 for the recovered liquid is arranged outside the blow-off unit. The lifting unit 12 for the recovered liquid transports the recovered liquid to the soaking tank for reuse.

[0033] The invention relates to a method for blowing off and recovering a liquid from a surface of a workpiece using the above-mentioned device, comprising the following steps: 1• Pressure unit 1 for circulation gas starts; circulation gas flows through the compressed air chamber 3 to the air outlet and is blown as compressed circulation gas onto the workpiece surface in the blow-off chamber 5; thus the liquid is blown off the surface of the workpiece to be treated and a liquid-gas mixture is obtained. 2• The liquid-gas mixture is directed through the air guide plate 6 into the gas-liquid separation chamber 7 for gas-liquid separation, whereby 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.

[0034] The next steps are as follows: Starting pressure unit 1 for circulating gas, by pressurizing the final gas, which flows from the exhaust opening of the final gas air space 10 of the blow-off unit and is then introduced through the air channel 2 into the compressed air space 3. After the compressor starts, a vacuum is created in the final gas air chamber 10 and a slight vacuum in the blow-off chamber 5. After the blow-off chamber 5 has been pressurized by a blower, the compressed gas is blown through the air duct 2, the compressed air chamber 3 and the discharge opening 4 into the blow-off chamber 5, where it is evenly distributed. After the air volume has been evenly distributed, no air is present at the upper opening of the blow-off chamber 5, with all the blow-off air being used and an internal equilibrium established (except that during the initial phase of commissioning and when lifting the workpiece into and out of the blow-off tank, a small amount of breathing gas enters and exits the upper opening of the blow-off tank). The pressurized gas forms an air supply cavity with low wind resistance in the compressed air chamber 3, and the pressurized gas is blown onto the workpiece at a specific angle through an air outlet located on the inner wall of the air chamber.

[0035] The workpiece to be treated, lifted from the soaking basin and carrying the liquid, is lifted through the upper opening of the blow-off chamber 5 into the blow-off chamber 5 so that the workpiece can be suspended or placed on the air guide plate 6, which is advantageous for blowing and blowing off. The wind speed of the compressed circulating gas for blowing off the liquid supply is 3–30 m / s. When the workpiece to be treated is blown off statically, the angle between the direction of the blowing wind and the plane (or tangent plane) of the workpiece is 15°–80°, with the wind blowing downwards or obliquely downwards. When the workpiece to be treated is blown off dynamically, the angle between the direction of the blowing wind and the plane (or tangent plane) of the workpiece is 15°–80°, with the wind blowing directly downwards or obliquely downwards.After blowing off for 5-30 seconds, the workpiece is lifted from the blow-off chamber through the upper opening into the subsequent cleaning container.

[0036] The blown-off liquid droplets and the gas-liquid mixture pass through the guide holes on the air baffle 6 into the gas-liquid separation chamber 7. The liquid droplets and the gas-liquid mixture flow through the filter material 8 located in the gas-liquid separation chamber 7, and the gas-liquid mixture impacts the surface of the filter material 8, causing the droplets to fall to the bottom of the filter material area. The final gas, from which most of the liquid has been separated, enters the final gas air space 10 through the air guide mesh 9. A low-resistance air space is formed in the final gas air space 10, and the final gas is directed through the final gas circulation pipe 11, which is located on the outer wall of the final gas air space 10, to the inlet of the compressor or fan.The liquid that drips onto the bottom of the filter material area forms a liquid layer, and this liquid layer is connected via a drain opening to a lifting pump for the recovered liquid, in order to return the liquid to the soaking tank. The workpiece to be treated is a chemically treated workpiece, produced by immersing various metal, non-metal, and semiconductor workpieces in a chemical liquid or by other processes such as pickling, alkali washing, degreasing, cyanidation, passivation, phosphating, chemical surface treatment, electrolysis, aluminum oxidation, electroplating, and chemical surface etching.

[0037] To further illustrate the present invention, the following detailed description is given by means of examples, which, however, are not to be understood as limiting the scope of protection of the present invention. Design and test

[0038] (1) Overview: * Device name: Machine for pickling, blowing off and recovering pickling liquid; * Implementation object: Pickling of copper soldering materials; * Characteristics of copper soldering materials: Materials include copper, stainless steel, silver, tin, etc., categorized according to the intended welding application; * The appearance of a washed workpiece is as follows: linear welding materials with a diameter of 1-3 mm are wound in a bundle of welding materials with a diameter of approximately 400-600 mm; * Purpose of pickling: Removal of metal oxides and oil stains from the surface of welding materials; * Pickling material: 10-13% sulfuric acid;

[0039] (2) Existing technological process and technical parameters of pickling. Technological process: Pickling tank → Draining on the tank → Primary water rinse → Secondary water rinse → Tertiary water rinse → Drying;

[0040] Description of technological process and technical parameter: Preparing a 10-13% sulfuric acid washing solution in the pickling tank; Lifting the workpiece into the pickling tank using an electric hoist; soaking the workpiece in acid, whereby the surface of the metal oxide reacts with sulfuric acid to form CuSO4 and water, and the soaking lasts 5-15 minutes; Lifting the workpiece with an electric hoist into the upper part of the pickling tank after soaking in acid, draining the liquid on the surface, leaving it to stand for 0.5-5 minutes, whereby the drained material liquid falls into the pickling tank; The previously drained workpiece is lifted into the primary washing and rinsing tank using an electric hoist, with the rinsing water coming from the secondary rinsing tank. After rinsing, the wastewater is discharged into the sewage treatment plant, containing the following pollutants: one or more contaminants such as pH value, copper, chromium, nickel, silver, and tin; The sulfuric acid concentration in the rinsing tank is less than 3%; Lifting the workpiece after primary water rinsing with an electric hoist into the secondary washing and rinsing tank, the rinsing water coming from the tertiary rinsing tank; after rinsing, the wastewater flows back into the primary washing and rinsing tank, the sulfuric acid concentration in the rinsing tank is less than 0.5%; Lifting the workpiece after a secondary water rinse with an electric hoist into the tertiary washing and rinsing tank, the rinsing water being clean tap water; after rinsing, the wastewater flows back into the secondary washing and rinsing tank, the sulfuric acid concentration in the rinsing tank is less than 0.1% and the pH value is 5.5-6.5; As the sulfuric acid concentration decreases continuously during the pickling process, the liquid is continuously carried through the workpiece into the rinsing tank, and the quantity is also continuously reduced. When the sulfuric acid concentration falls below 10%, or the quantity is so small that the sulfuric acid can no longer flood the workpiece, pickling solution must be added in a timely manner.

[0041] (3) Technological process and technical parameters for pickling in the embodiment of the invention.

[0042] Pickling tank → Dewatering on the tank → Device for pickling the liquid and circulation of the pressurized gas and blow-off and recovery of the liquid supply → Primary water rinse → Secondary water rinse → Tertiary water rinse → Drying;

[0043] Description of technological process and technical parameters: - Preparing a 12.3% sulfuric acid wash solution in the pickling tank; - Lifting the workpiece into the pickling container using an electric hoist; - Soaking the workpiece in acid, whereby the surface of the metal oxide reacts with sulfuric acid to form CuSO4 and water, and the soaking lasts 10-15 minutes; - Lifting the workpiece with an electric hoist into the upper part of the pickling tank after soaking in acid, - Draining the liquid from the surface, - Leave to stand for 1 minute, allowing the drained material liquid to fall into the pickling container; - Lifting the previously drained workpiece into the machine for pickling, hanging, blowing off and recovery using an electric hoist.

[0044] The compressed circulating gas is used to blow off and recover the liquid from the workpiece surface. The pickling, hanging, blowing, and recovery machine is used to recover the pickling liquid. The technical parameters for the operation of the pickling, hanging, blowing, and recovery machine are as follows: * Step 1: The parameters of the blower for venting the pressurized gas: Blower air volume 800 m³ / h 3 / h, wind pressure 2740 Pa, motor power 1.5 KW, and the air velocity of the compressed gas on the workpiece surface during operation is 35 m / s; * Step 2: The parameters for the compressed air supply, the air outlet and the blow-off: At the blower outlet, pressurized gas enters the air space for air distribution, with 24 discharge openings 4 being located on the inner wall of the air space. The wind direction of the discharge openings 4 is as follows: when the workpiece is blown off statically, the angle between the direction of the blowing wind and the plane (or tangent plane) of the workpiece is 60°, and the wind blows obliquely downwards; the blow-off mode is a gap mode, and the blow-off time for each workpiece is 0.5 minutes; * Step 3: Parameters for the gas-liquid separation of the liquid-carrying gas: The bottom of the blow-off chamber 5 is provided with a porous air guide plate 6 with an aperture of 30 mm, a hole spacing of 60 mm and a rectangular distribution of the hole positions; the area for gas-liquid separation is provided with spherical ceramic filter materials 8 with a particle size of 8-10 mm; * Step 4: Parameters of the feed pump for recovering droplets of the blown-off chemical liquid: 1m 3 / h, stroke 5 m, motor power 0.38 KW, PP plastic pump; * Step 5: Parameters for the recovery of the vented end gas, wherein the vented end gas is a low-humidity end gas containing a specific liquid feed, where the liquid concentration is 20-30 g / m³ 3 is and the final gas is introduced and returned to the fan.

[0045] The sulfuric acid concentration in the primary washing and rinsing tank is less than 3%; the sulfuric acid concentration in the secondary washing and rinsing tank is less than 0.5%; the sulfuric acid concentration in the tertiary washing and rinsing tank is less than 0.1% and the pH value is 5.5-6.5; with the continuous decrease in the sulfuric acid concentration during the pickling process, the liquid is continuously carried through the workpiece into the rinsing tank, and the quantity is also continuously reduced; the sulfuric acid concentration in the pickling tank is less than 3%.

[0046] *Technical parameters for tertiary countercurrent flushing are as follows: The sulfuric acid concentration in the primary washing and rinsing tank is less than 3%; the sulfuric acid concentration in the secondary washing and rinsing tank is less than 0.5%; the sulfuric acid concentration in the tertiary washing and rinsing tank is less than 0.1% and the pH value is 5.5-6.5; with the continuous decrease in the sulfuric acid concentration during the pickling process, the liquid supply from the workpiece is continuously transferred to the rinsing tank, and the quantity is also continuously reduced; the sulfuric acid concentration in the pickling tank is less than 3%.

[0047] (4) Table 1 shows the comparison of the effects between the embodiment of the invention and the existing pickling process: Weight of the workpiece Each workpiece weighs 15-20 kg, cleaning 24 workpieces, 24 workpieces together weigh 423.6 kg. 418.3 kg The weight of the workpiece in the pickling tank is the weight of the workpiece before washing. The weight of the workpiece after three stages of rinsing is the weight after rinsing and drying. Description of the liquid in the existing process Before use: The volume of sulfuric acid is 216 L and the concentration is 12.3%. After use: The volume of sulfuric acid is 200.2 L and the concentration is 10.2%. Add 6.294 kg of sulfuric acid (98% sulfuric acid) to restore the pre-use condition. None (during testing, both processes perform dewatering on the tank, and the dewatering time is the same, and the recovery quantity of this part is ignored in the comparison). Provided that the sulfuric acid concentration in the flushing tank is controlled to 2.5-3%, the wastewater output is 74 L. The sulfuric acid concentration in the rinsing tank is regulated to 0.2-0.5%, the pH value is 2-3, and the backwash water volume is 4 L. The sulfuric acid concentration in the rinsing tank is regulated to <0.1%, the pH value is between 5.5 and 6.5, and the consumption of clean rinsing water is 74 L. The condition before use refers to: After use, 40% sulfuric acid and clean water are used to adjust the sulfuric acid concentration and the volume of the pickling tank to the condition before use. In this version fo The tank is adjusted to a sulfuric acid concentration of 12.3%, and the volume of 216 L is 98%. Description of the liquid in the process of the invention Before use: The volume of sulfuric acid is 216 L and the concentration is 12.3%. After use: The volume of sulfuric acid is 199.7 L and the concentration is 10.5%. Add 1.137 kg of sulfuric acid to the recovered liquid and add 4.554 kg of sulfuric acid (98% sulfuric acid) to restore the pre-use condition. The volume of sulfuric acid recovered from the hanging liquid is 9.15 L, the concentration is 11.3%, the amount of sulfuric acid recovered is 1.137 kg, and the recovery rate of the liquid carried by the workpieces is 56%. Under the conditions that the volume of the sulfuric acid supply liquid is 7.15 L and the concentration is 11.3% (calculated quantity), the concentration of the sulfuric acid in the rinsing tank is controlled to 2.5-3% and the wastewater output is 35 L. The sulfuric acid concentration in the rinsing tank is regulated to 0.2-0.5%, the pH value is 2-3 and the amount of backwash water is 35L. Provided that the sulfuric acid concentration in the rinse tank is controlled to be less than 0.1% and the pH value is between 5.5 and 6.5, the amount of rinse water is 35 L. The condition before use refers to: After use, 40% sulfuric acid and clean water are used to adjust the sulfuric acid concentration and the volume of the pickling tank to the condition before use. In this configuration, the tank is brought to a sulfuric acid concentration of 12.3%. The initial state of 216 L is 98% sulfuric acid replenishment. Comparison of the effects between the process in the invention and the existing process Design: The amount of sulfuric acid recovered is 1.137 kg, the amount replenished is 4.554 kg (98% sulfuric acid), and the consumption of sulfuric acid is reduced by 20.3%. The existing process has no recovery; implementation form: The amount of sulfuric acid in the solution to be recovered is 9.15 L, the concentration is 11.3%, and the amount of sulfuric acid recovered is 56%. Compared to the existing process, wastewater output in this version is reduced by 39 liters, which corresponds to a reduction of 52.7%. In comparison to the existing process, the counter-current rinsing water volume of the design is reduced by 39L, which corresponds to a reduction of 52.7%. Compared to the existing process, the consumption of clean rinsing water is reduced by 39 liters, which corresponds to a reduction of 52.7%.

[0048] The invention relates to a device for blowing off and recovering a liquid located on the surface of a workpiece by means of compressed circulating gas, wherein the device comprises: a pressure unit 1 for circulating gas, a blow-off unit connected to the pressure unit 1 for circulating gas by an air channel 2 and a lifting unit 12 for the recovered liquid, which is connected to the blow-off unit by the supply pipe.

[0049] The blow-off unit comprises a compressed air chamber 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 a final gas air chamber 10; the pressure unit 1 for circulating gas comprises a compressor; the air inlet of the compressor is connected to the air outlet of the final gas air chamber 10, and the air outlet of the compressor is connected to the inlet of the compressed air chamber 3; the outer wall of the compressed air chamber 3 and the 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 compressor; the inner wall of the compressed air chamber 3 is provided with a blow-off opening 4; the circumferential wall of the blow-off chamber 5 and the inner wall of the compressed air chamber 3 form 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 an air guide plate 6; the air guide plate 6 vertically divides the central area of ​​the blow-off unit into a blow-off chamber 5 and a gas-liquid separation chamber 7; the air guide plate 6 is provided with guide holes, the gas-liquid mixture formed entering the gas-liquid separation chamber 7 through the guide holes; a filter material 8 is arranged in the gas-liquid separation chamber 7; an 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; an annular end gas air space 10 is arranged around the air guide mesh 9. Compared to existing natural blow-off methods for workpieces, the device reduces chemical consumption by 10-20%; the amount of chemical fluid brought into the cleaning process by workpieces is reduced by 40-70%; if this portion of the chemical fluid is fully recovered, wastewater emissions and wastewater treatment costs in the surface treatment industry can each be reduced by approximately 50%, which has a positive impact on resource recovery, pollutant emission control, water conservation, etc., and significantly improves the level of clean production and environmental protection in the surface treatment industry. The device only needs to blow a circulating, low-humidity gas onto the workpiece, thereby reducing the cost of the device and the operating costs of the spraying process. In the invention, the gas in pressure unit 1 is the circulating, low-humidity gas after gas-liquid separation, which is why a continuous supply of pure gas is not required, thus saving on the cost of pure gas (given that the liquid supply readily reacts with air, it is particularly important to blow off the liquid supply with inert gas as the pure gas).

[0050] The device eliminates the need for exhaust gas capture and cleaning processes required in spray stripping processes. Experimental results show: a 56% recovery rate of the material solution carried by the workpieces, a 52.7% reduction in subsequent cleaning water consumption, and a 52.7% reduction in cleaning wastewater volume.

[0051] Given that the feed liquid does not produce any volatile contaminated end gases, or for other reasons, there is no need to use end gas recirculation methods and equipment. If the method and equipment features of other parts, with the exception of the end gas circulation tube 11, fall within the scope of the above protective clauses, they also fall within the scope of protection of the invention.

Claims

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 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 that is connected to the air outlet of the pressurization unit; the inner wall of the compressed air space (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 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) subdivided 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 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). 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 bottom; 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 circulation gas and also with a connecting pipe that is connected to the lifting unit (12) for recovered liquid. 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. The device according to claim 1, wherein the blow-out opening (4) is arranged to be fixed or movable with the workpiece. 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 surface 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 surface 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 when the inner wall of the compressed air space (3) has a round structure. The device according to claim 1, wherein the pressurization unit is a fan or a blower or an air compressor. 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 mm²; or the filter material (8) is a stacked spherical or columnar filter material (8) with a particle size of 2-20 mm. A method for blowing off and recovering a liquid from the surface of a workpiece using the device according to any one of claims 1-7, characterized in that it comprises the following steps: The pressure unit (1) for circulating gas starts; circulating gas flows through the compressed air chamber (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 chamber (10); the liquid obtained after separation is transferred for reuse by the lifting unit (12) for the Fluid intake directed. The method according to claim 8, wherein the wind speed of the compressed circulating gas for blowing off liquid is 3-30 m / s. The method according to claim 8, further comprising: when the workpiece to be treated is statically blown off, the angle between the direction of a blowing wind and a plane or the tangential 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 tangential plane of the workpiece is 15°-80°, and the wind blows directly downwards or conversely obliquely downwards.

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