The Type-14 diaphragm valve features improved body to bonnet sealing performance, visual position indication, weir design for excellent throttling capabilities and built in travel stop to prevent over-tightening and eliminate compressive strain. Bubble tight sealing can be achieved even in tough applications containing suspended particles or slurrys. Asahi's Type-14 diaphragm valve features a layered EPDM/PTFE diaphragm which can accept the addition of a PVDF gas barrier for aggressive chemicals such as Sodium Hypochlorite which produces an off-gas that can permeate the PTFE layer, unlike laminated PTFE diaphragms which cannot accept a PVDF membrane and actually can become de-lamintated in this highly corrosive environment leading to a potentially hazardous situation.