Valveless Filter

Structural Features and Brief Description

The series of steel gravity-type valveless filters is used for surface water purification, iron and manganese removal from groundwater recirculation, removal of suspended solids from production wastewater, post-treatment filtration after biochemical treatment and secondary sedimentation pond for organic wastewater, and filtration of indoor swimming pool water. It is an appropriate water treatment equipment.

Gravity-driven valveless filter with automatic operation via hydraulic force; no need for valves for inlet, outlet, flushing, and drainage. Low operating costs, easy management, and high reliability. Automated operation, integrated equipment design. The water tank, filter, and backwash tank are assembled as one, featuring a compact structure. Users only need to prepare the equipment foundation and connect the inlet and outlet pipes as required to start operation. Additionally, all filters are equipped with a top cover for good hygiene protection and can be set up outdoors. Compared to reinforced concrete filter basins, they have a lower self-weight and can use asphalt sand flexible foundations.

Operating Principle

Raw water enters the distribution box, which then evenly distributes it to the filter beds. The water is filtered from top to bottom through the filter layer, flows through porous plate water caps to the accumulation area, and clean water is injected into the storage tank via connecting pipes. Once the tank is full, the water is discharged through an outlet pipe into the clear water pool. The filter layer continuously retains suspended particles, gradually increasing the resistance. This causes the water level in the siphon pipe to rise continuously. When the water level reaches the siphon auxiliary pipe opening, water falls from it, utilizing the suction pipe to remove air from the siphon下降管. When a certain vacuum level is reached, siphon action occurs. At this point, the water in the pipe flows from bottom to top through the filter layer, performing backwashing on the filter material. When the water level in the backwashing tank drops to the siphon destruction pipe, air enters the siphon pipe, disrupting the siphon action. Once the backwashing of the filter bed is complete, it enters the next cycle of operation. During backwashing, the filter beds alternate, with the water from two tanks shared for a single filter bed backwash.

Operation Overview

The operation process of a valveless filter is generally as follows: Water supplied through the inlet pipe passes through the filter layer, collects in the lower water collection chamber, and then flows to the upper rinsing water tank via connecting pipes. Once this tank is filled with water, it begins to deliver water outward. Its failure and cleaning process is: As the operation time increases, the resistance in the filter layer grows, causing the water level in the siphon riser pipe to rise accordingly. When the resistance continues to increase and the water level reaches the siphon auxiliary pipe opening, water rapidly falls from this pipe. At this point, air in the main siphon pipe (a collective term for the siphon riser and siphon drop pipe) is continuously drawn out through the suction pipe 10 (flows into the drain tank and then into the atmosphere with the water), creating a vacuum in the main siphon pipe. This vacuum causes the water levels in both the siphon riser and drop pipes to rise quickly. When these two streams of water converge, siphon action is formed. The water in the filter chamber is immediately drawn out by the siphon pipe, and the water in the rinsing water tank rapidly reverses back into the filter layer, creating an automatic backwashing. This causes the water level in the rinsing water tank to drop. When it reaches the opening of the siphon destruction pipe 11, air enters the siphon pipe, disrupting the siphon action, and the rinsing process ends, initiating the next operational cycle.

The water distribution tank and U-shaped inlet pipe set in the valveless filter are designed to prevent air from entering the pool. Because when air is吸入, it may not form a siphon in the later stage of operation, and without this U-shaped pipe, the inlet pipe would become a siphon-damaging pipe in the later stage of backwashing.

As the valveless filter begins operation, the filter media layer is relatively clean, and the difference in water level between the inside and outside of the siphon riser tube indicates the initial head loss of the filter pond, generally about 20 cm. As the filtration progresses, impurities in the filter layer gradually increase, causing the resistance to slowly increase. However, since the inflow rate remains constant, the water levels in the inflow pipe and the siphon riser tube automatically rise slowly.

Installation

The equipment installation and acceptance standards specified in the design documents are followed for hoisting, alignment, positioning, and securing. The orientation errors of pipe openings are ensured to meet the specifications, and the water outlet device's water cap is carefully inspected for any loosening or damage.

Technical Specifications