In the cooling tower, the cooling capacity of the water spray filler accounts for more than 80% of the cooling capacity of the whole cooling tower, so the selection of the water spray filler is very important in the design of the cooling tower. According to the design requirements and water quality conditions, the S-wave film type water spraying filler independently developed by our company is selected as the water spraying filler for this bidding project. The filler sheet adopts automatic vacuum blister molding, and the filler sheet after molding is more uniform and beautiful, which fully ensures that the mechanical properties and various indicators of the filler meet or exceed the national industry standards.

(1) The water drenching filler has the basic technical properties of good thermal performance, low ventilation resistance and low calculated tower water temperature; It has the basic technical requirements of good assembly rigidity and strong bearing capacity, does not deform, distort or lodge under normal applicable conditions, maintains stable and efficient operation all the year round, meets the technical requirements of normal use under various climatic conditions in the local area, and has a service life of not less than 30 years.

(2) The flat sheet of water drenching filler adopts polyvinyl chloride (PVC) flat sheet of filler, adopts cold-resistant type, the color is the original color of raw material, the appearance color is consistent, and no recycled material is added. The water drenching filler can resist the cold climate and does not crack or brittle under the condition of the lowest temperature. Especially in winter, it can maintain a good standby state without water.

(3) The surface of the flat sheet of water drenching filler is flat and free of obvious holes, wrinkles and bubbles; There are no impurities with a particle size greater than 1.0mm, the number of impurities with a particle size of 0.6mm ~ 1.0mm does not exceed 20/m2, and the dispersion degree does not exceed 5/(10cm × 10cm). The edge of the sheet shall be smooth and straight without crack or notch. The design thickness of the flat sheet is between 0.35 mm-0.45mm.

(4) Other technical requirements and physical and chemical performance indexes of the flat sheet of the water-drenching filler conform to the relevant provisions of the the People's Republic of China electric power industry standard DL/T742-2001 "Technical Conditions for Plastic Parts of Cooling Towers.

(5) The requirements and performance indexes of water-drenching filler molding pieces, assembly blocks and adhesives conform to the relevant provisions of the the People's Republic of China electric power industry standard DL/T742-2001 "Technical Conditions for Plastic Parts of Cooling Towers.

(6) the water drenching filler can bear the weight of water film, scale, the load of the lower filler, etc.; the water drenching filler has flame retardant properties, oxygen index ≥ 40; the water drenching filler does not deform geometrically at a temperature of 65 ℃.

(7) The water drenching filler adopts the most advanced form. The material sheets are staggered and bonded into blocks. The bonding rate is not less than 95%, and the total height is about 1.5m.

(8) The special binder for PVC plastic fillers is formulated from vinyl chloride polymer and is a non-toxic material.

(9) The acceptance of water drenching filler shall be carried out according to the relevant provisions of the the People's Republic of China electric power industry standard DL/T742-2001 "Technical Conditions for Plastic Parts of Cooling Towers. The product has the physical and mechanical properties, chemical properties and stability (temperature change resistance, aging resistance and corrosion resistance, etc.), as well as thermal characteristics and resistance characteristics and other parameter reports issued by the national authoritative testing organization.

(10) Binder

a) The special adhesive for PVC plastic filler is made of polyvinyl chloride polymer. Under various environmental conditions, its bonding curing performance meets the process requirements of bonded assembly blocks.

B) The type of adhesive is determined according to the ambient temperature. When the ambient temperature is lower than 10 ℃, the low-temperature quick-drying adhesive is used.

c) The bonding strength of the adhesive shall meet the requirements of Table 1.3.7.

Table 1.3.7 Adhesive Properties of Special Adhesives for PVC Fillers

Water filling material: modified PVC, the use of non-toxic materials do not add recycled materials, and fully consider the characteristics of water quality, to ensure that the service life of not less than 20 years.

Model: S30-1, three-layer filler.

The thickness of the water-drenching filler substrate shall not be less than 0.4mm, the weight per cubic meter shall not be less than 20kg, the flat compressive strength of the filler block shall be greater than 300kg/m2, and the spacing between the filler pieces shall not be greater than 26mm.

When the filler is installed, it shall be placed at the orthogonal position, and there shall be no gap through the sky. The filler, tower wall and column beam are also filled tightly; the allowable error of spacing between water-drenched filler assembly blocks is ± 1.0mm. The allowable error of the main geometric dimensions of the sheet shape is not more than 5%, and the maximum error is not more than 1mm.

The physical and chemical performance indicators of the filler sheet comply with the relevant provisions of the national power industry standard DL/T742-2019 "Technical Conditions for Plastic Parts of Cooling Towers", as shown in the following table:

Physical and mechanical properties of raw sheets

Packing water density is 14.3 m3/(m3/h), the height of packing is 1.5 m, and the volume of packing is 541.5 m3.

● The production of our filler starts from the purchase of high-quality SG5 PVC resin powder, dyeing, kneading, granulating, calendering and molding, and the automatic production line produces in large quantities, with stable quality, good quality control and low defective rate. Our company never take the manufacturing method of purchasing PVC sheet and then the second processing molding.

● Our filler contains rubber and plastic components, PVC is modified. After modification, the softening point and melting temperature of PVC resin are improved, and the processing and molding is more difficult than that of general PVC, but it has good heat resistance, moisture resistance, acid resistance, alkali resistance, corrosion resistance, flame retardant performance and mechanical properties. The flexibility and anti-aging performance of the filler are greatly improved. The water spraying filler shall have flame retardant property and oxygen index ≥ 40. Under the condition that the temperature is 65 ℃, the geometric deformation should not occur.

● Our filler contains light stabilizer-carbon black. Under the action of light, the plastic will degrade, the light energy of ultraviolet light is equivalent to the chemical bond energy in the plastic molecule, and the light aging of the plastic filler is caused by the absorption of ultraviolet light. Once the photochemical reaction begins, oxygen greatly accelerates the process. Therefore, light shielding agent should be added to the plastic to prevent light from passing through, so that the plastic is not affected by ultraviolet rays. Carbon black is the most efficient light shielding agent, and it is also a radical chain terminator for plastics. Carbon black is added to PVC filler, on the one hand, it has efficient light shielding effect, control the external environmental factors that cause the aging of the filler, and at the same time, it has the effect of passivating the plastic molecular chain, preventing the aging reaction from occurring, and playing a role from the internal cause of the molecular structure.

The allowable error of spacing between assembled blocks of water drenching filler is ± 1.0mm. The allowable error of the main geometric dimensions of the sheet shape is ≤ 5%, and the maximum error is ≤ 1mm.

The filler shall be placed in the orthogonal position during installation, and there shall be no gap through the sky. Filler and the tower wall, column beam between the squeeze tight fill.

The water drenching filler is assembled into blocks by bonding type, with firm bonding and good overall rigidity. The adhesive has water resistance, heat resistance (65 ℃), cold resistance (-35 ℃), aging resistance and other properties, the bonding rate is ≥ 98%, and the shear strength after bonding for 24 hours is greater than 3.3MPa.

The drenching packing assembly block has sufficient rigidity and strength. Under the condition of simple support, the standard specimen has no obvious deformation at the bearing and loading surface under the uniform load of 300kg/㎡, no residual deformation after unloading, and no looseness at the connection point between the pieces. The assembly block of water drenching filler shall not be deformed at 65 ℃, and there shall be no degumming at the bonding part.

(11) PVC special connectors are used for connection between filler sheets. The tensile strength of the connectors is ≥ 40MPa, the fracture elongation rate is ≥ 60%, and the thickness of the filler sheet substrate is not less than 0.4mm..

(12) When the packing is installed, cut small pieces of packing to fill irregular gaps according to the plane layout in the tower. There is no sky gap. The assembly block and the boundary objects such as column beam tower wall are tightly packed and filled to ensure that the whole tower is covered tightly. The filler shall not be deformed, and the installation shall be smooth and uneven. When the filler block is placed, the upper and lower discharge holes shall be staggered so that the water can be fully dispersed and cooled.

(13) Overhaul walkway board shall be laid on the top of the filler. The overhaul walkway board shall be made of I-steel composite grid. The overhaul walkway board shall be laid with 20% of the top plane. The overhaul walkway board shall have sufficient bearing capacity for overhaul personnel and overhaul parts.

(14) In order to ensure the uniform air distribution of the filler, a safe and reliable support structure is provided for the water-drenching filler to ensure the safety of installation and maintenance personnel. The packing bracket can ensure sufficient strength during the service life of the cooling tower.

3.5 packing

(1) The film type high-efficiency packing is adopted, and the physical and chemical performance indexes of the packing pieces meet or exceed the relevant provisions of DL/T 742 -2019 "Technical Conditions for Plastic Parts of Cooling Towers" of the Electric Power Planning Bureau of the Ministry of Energy.

(2) filler sheet using modified PVC material, do not add recycled materials.

(3) The sheet spacing is 20±1mm.

(4) Filler Sheet The thickness of the base sheet was 0.4±0.03mm.

(5) Filler bonding molding, the bonding rate is not less than 95%, and the shear strength after 24 hours of bonding is greater than 3.3Mpa.

(6) Flat compression strength of packing block ≥ 300kg/m2.

(7) the flame retardant oxygen index of the filler is more than 40.

(8) Packing height ≥ 1.2m.

(9) The installation mode of the filler is hoisting type. The filler is hoisted on the upper concrete beam by using the filler through the pipe and the lifting bar. The bottom of the filler is free of any obstruction, the air flow field is smooth, and the ventilation resistance is small. The filler passing pipe and hanger bar shall be made of stainless steel.

(10) Filler flat sheet and formed sheet must be manufactured by the supplier's own factory, and subcontracting is not allowed.

(11) Hanging bar adopts M8 stainless steel round steel, and hanging pipe adopts φ51 × 1.5 stainless steel round pipe.