1,800 square meters of ice hockey arena, flatness error is not more than 5 mm how to do?
Following several women’s ice hockey group matches, men’s ice hockey group matches were held at the National Stadium recently.Ice hockey field, athletes fiercely intercept, defense, collision, fully and delightfully wet ice hockey duel feast can not leave their feet that piece of smooth and smooth ice.How was this “flat, bright and smooth” ice made?The 11 layers of structure beneath the ice hold secrets.As the world’s top event, ice hockey games in the Winter Olympics have very strict requirements on the ice surface.”In order to make the ice as flat as possible, the first thing to do is to make sure that the 11 structural layers beneath the ice are no more than 5 millimeters flat.”Bai Jingwei, manager of the ice making project of the China Construction And Installation National Stadium, told reporters that the flatness error of the 1,800-square-meter ice rink is no small challenge.According to Bai, the national Stadium is not a single block of concrete under the ice, but as many as 11 layers of structure.Starting from the bottom of the cushion, the top 10 layers of the structure undertake moisture-proof, insulation, waterproof, heating, cooling and many other functions.In order to control the flatness of the ice surface within 5 mm after layer upon layer, the project team introduced Swiss laser paver with laser ranging and other detection equipment. During the construction process, the structural layer of the ice surface was checked layer by layer and corrected deviation at any time to ensure the smooth and flawless ice surface.The “flatness” of the ice requires precise technique and ingenuity.Among them, frost resistant concrete surface layer is one of the most challenging structural layers.”The ice pouring area is 1800 square meters, which belongs to the seamless construction of super-large area concrete, which needs to be completed by one-time continuous pouring.”To prevent cracks, the project team worked with ice experts and manufacturers to determine the optimal mix of concrete, Bai said.”In order to make the ice achieve the ‘bright’ effect, the laying position of the ice pipe is very important.”Bai Jingwei explains that because the ice making pipeline is only 2 to 3 centimeters away from the ice surface, its laying positions are too close or too sparse, and a little closer or far from the structural layer, which will lead to uneven temperature of the ice surface after pouring ice, thus making the ice surface white or black, and unable to form a bright effect.But how do you ensure that ice pipes are spaced evenly?Finally, the project team realized the uniform laying of the cold dish pipeline through the customized M-shaped bracket, and controlled the upper and lower spacing of the ice-making pipeline at 2 cm and the left and right spacing at 8 cm.The resulting ice, bright white as a mirror, who can not help but sigh: “really beautiful ice!”In addition to bright and clean surface, high quality ice also requires high precision control of the ice machine group.”We use frequency conversion equipment such as low-temperature ethylene glycol screw ice machine group to ensure that the ice temperature of the main ice-making machine during the competition is -20℃, and ensure that the ice temperature can be adjusted from -5℃ to -7℃.”In addition, on-site operation and maintenance teams patrol the ice-making system every hour, Bai said.The ice machine room also has professional and technical personnel on call at any time to coordinate with the international ice maker to pour ice and repair ice in real time, timely and accurately adjust the outlet temperature of the ice machine group, and control the temperature fluctuation within 0.2℃.Skating: “2+1+4” gradually cooling the ice “skating”, is also the ice sports put forward a hard index of the ice.”To create high-quality ice, the preparation before making ice should not be neglected.””One of the conditions for making ice is for the temperature to drop to -10°C, but the temperature of the ice rink does not drop all at once,” bai said.In order to ensure the performance of the ice rink, the project team adopted the method of “2+1+4” to gradually cool the ice rink under the guidance of the main ice maker.Rink cooling is divided into three steps.First, the ice surface slowly drops from 10°C to 5°C every day for 2 consecutive days. When it drops to 0°C, it actively maintains for 1 day. Then it slows down 3°C every day for 4 consecutive days.Then, through the ice bottom ice, paint, ice, line, ice layer five layers of construction technology, meet the requirements of the top competition “smooth” ice was born.From design to implementation, the ice of the National Stadium embodies the concept of “green Olympic Games” everywhere.According to the report, the innovative use of a new environmentally friendly refrigerant, the global warming potential of the Beijing Winter Olympics compared to conventional refrigerants reduced by 68 percent, which will help the Beijing Winter Olympics to become the history of the lowest environmental impact of refrigerants on ice venues.