HBzhan Content Introduction: In drainage engineering,grilleIt is used to remove larger suspended solids that may clog the water pump unit and pipeline valves, and ensure the normal operation of subsequent treatment facilities. It is composed of a set (or multiple sets) of parallel metal bars and frames, which are installed obliquely in the inlet channel or at the inlet of the collection well of the inlet pump station to intercept large suspended solids and impurities in the sewage.
　　
1. General Technical Requirements for Products
　　
1) The gap between the bars is determined based on the type, flow rate, representative debris type, and size of the sewage. The general selection range is as follows: mechanical cleaning: 3-25mm; manual cleaning: 5-15mm; screen mesh: 0.1-2mm.
　　
2) In large and medium-sized sewage stations, two mechanical grilles should be installed: one is a coarse grille with a diameter of 10-40mm, and the second is a fine grille with a diameter of 3-10mm. In small sewage stations, only one grille should be installed, and the gap between the bars should be 3-15mm.
　　
3) Flow velocity through the grid: The flow velocity of sewage in the channel in front of the grid should be controlled at 0.4-0.8m/s, and the flow velocity through the grid should be 0.6-1.0m/s. The head loss of water passing through the grid is related to the flow velocity, and should generally be controlled between 0.1 and 0.3 meters. The bottom of the canal behind the fence should be lowered by 0.1-0.3m compared to the front of the fence.
　　
4) The effective water passage area of the grille is calculated based on a flow rate of 0.6-1.0m/s, but the total width is not less than 1.2 times the width of the inlet pipe channel. The inclination angle of the grille should be 45 ° -75 °. If it is an artificial grille, the installation angle should be 30 ° -60 °.
　　
5) The grille must be equipped with a workbench, which should be 0.5m higher than the highest water level in front of the grille. Safety and flushing facilities should be installed on the workbench. The width of the aisle on both sides of the workbench should not be less than 0.7m. The width of the front of the workbench should not be less than 1.2m when manual slag cleaning is used, and not less than 1.5m when mechanical slag cleaning is used.
　　
6) Mechanical ventilation facilities should be installed between grilles, commonly including axial flow exhaust fans. If the sewage contains toxic gases, a detection and alarm system for toxic and harmful gases should be installed between the grids. Lifting equipment should be installed between large and medium-sized grids to facilitate equipment maintenance and daily removal of grid debris.
　　
7) The rake teeth and chain links of the grille are soaked in water for a long time. In order to prevent corrosion and rust, high-strength plastic or stainless steel is generally used, and the chain shaft is also made of stainless steel.
　　
2 Categories Product Name
　　
Commonly used mechanical grilles can be divided into several types as listed in the table above: arm type grille machine, chain type grille machine, steel rope type grille machine, rotary type grille machine, etc.
　　
Select the main technical indicators (or factors)
　　
The main technical indicators that need to be controlled when selecting equipment include effective depth (trench depth), effective width (grid width), grid gap, installation angle, inlet water quality, water temperature, etc.