CB/T 295-2000 CB/T 4444-2017 Type A Mushroom Ventilators for ship

CB/T 295-2000 CB/T 4444-2017 Type A Mushroom Ventilators for ship

Mushroom Ventilator is installed on deck for natural ventilation or mechanical ventilation devices .

CB/T295 Mushroom Ventilation is generally used for kitchen and accommodation of ventilator regulating screw, simply turn adjusting handwheel indoors can reach the purpose of adjusting the opening size.

CB/T 4444-2017 is a new edition of CB/T 295-2000, main difference of them are thickness of vent and air pipe, and diameter of screw rod.

Process requirements

1. Surface: should be flat and smooth, without sharp edges, distortion, or skew.

2. Size error:  ±3mm, and the deviation of the verticality is 2/h1000 (h is the height of the ventilator cylinder)

3. The welding surface: free of cracks, slag inclusions, burn-through, and unfused defects.

4. The opening of the weather-tight cover of the fungus-shaped ventilator for ships should be flexible, and the movable part should be coated with neutral lubricating grease.

5. Derusting: the internal and external surfaces of the steel parts of the fungus-shaped ventilating cap should reach the Sa2 level or St2 level specified in GB/T8923, and then two antirust primers.

Note: the height h of air pipe is decided by customer, and the support rib plate is only required when the h is over 900mm.

Structure descriptions:

1. Vent head

2. Seal packing

3. Brake pin

4. Rodent-proof, insect-proof net or fire net

5. Screww rod

6. Air pipe

7. Hand wheel

Obviously, type A CB/T 295's opening & closing is operating from inside.  

Type A CB/T 295-2000 Models: