Cast-in-place filter head, filter plate

Filter Plate Fitting

Overall Filter Plate Technical Requirements

3.4.2 Filter Heads and Molds

Filter Head

Shape Description

The filter head is composed of a filter cap, filter rod, gasket, fixing ring, and cover.

The filter cap is approximately cylindrical, with the top diameter slightly larger than the bottom diameter, and an inclination angle of 95°. The cap features 36 narrow holes, evenly distributed, which gradually expand from the filter material side to the interior of the cap head. The hole width is 0.4±0.05mm, and the length is 24±0.05mm. Each cap head has an opening area of 345.6mm². The opening ratio is 1.84%.

Filter rod inner diameter: 17 ± 0.5mm, with external thread. The top of the filter rod features a circular air intake hole with a diameter of 2 ± 0.05mm; the bottom has a narrow, elongated air intake hole, with a length of 65 ± 0.05mm and a width of 1.5 ± 0.05mm.

The fixed ring has a height of 80mm, equipped with an internal thread, and the inner diameter matches the outer diameter of the filter rod.

Each fixed loop is equipped with a cover to prevent concrete and debris from entering.

Gasket serves as the connecting pad between the filter rod and the fixed ring.

Installation Method

The filter cap is fitted onto the filter rod, with the rod's top cover seated at the top of the filter cap. The fixing ring is inserted into a conical pre-bolted piece within a layer of prefabricated board, which is embedded in the poured-in-place second floor board. The filter head is mounted on the fixing ring via the threaded connection on the filter rod, with a washer installed between the rod and the fixing ring.

The center deviation of the filter head within a single pool does not exceed ±1.5mm. The center deviation of all filter heads within all filter pools does not exceed ±5mm.

③ Material Requirements

Filter caps, filter rods, fixing rings, and ring covers are made of polyethylene.

All components on the filter head must withstand pressure and not break upon installation.

Materials used for filter heads should be non-toxic and free of side effects, all complying with the provisions of GB/T 17219, "Safety Evaluation Criteria for Equipment and Protective Materials for the Transmission and Distribution of Drinking Water."

(2) Template

Templates are designed by suppliers based on the overall dimensions of each filter plate and the required center spacing between filter beams.

The template is rectangular, evenly distributed with conical embeds for securing the filter head. Each conical embed is equipped with a cover to prevent concrete and debris from entering.

The design of the template requires an even distribution of filter head placements on each complete filter plate, with filter head spacing meeting the reinforcement requirements.

The template is a fabrication template for a precast board, its size should not be too large for ease of installation.

The template is made entirely of polystyrene/ABS material.

The materials used in the template must be non-toxic and free of side effects, and comply with the provisions of GB/T 17219, the "Safety Assessment Standard for Equipment and Protective Materials for the Transmission and Distribution of Drinking Water."

Reinforcement should be reserved on the top surface of the filter beam, bending 90° diagonally to both sides respectively, and welded to the main steel of the cast-in-place slabs on both sides. The reserved reinforcement should avoid the position of the balanced gas holes.

The filter pool bottom slab has reserved rebars at the filter beam section, which are welded to the vertical main rebars of the filter beam.

The filter pool wall is at the level of the filter plate, surrounded by grooves of 20-40mm depth, which are the same height as the filter plate thickness. Reinforcement bars can be embedded in the grooves as needed, and焊接to the main bars of the cast-in-place slab.