1.Packing element is spherical or tapered type with massive storage volume, low operation pressure and excellent sealing function;

2. Bonnet is hemispherical-shaped, so there is no stress concentration on bonnet whenever bearing the pressure.

3.Bonnet and body are connected by a wedge block, so the pressure is evenly distributed;

4.Packing element is interchangeable with similar overseas products;

5.Use observation hole to check the life span of the packing element;

6.Piston is set in low position to have a shorter moving distance; Use wear ring on piston.