| 摘要 |
A backing diaphragm (5) in a diaphragm valve for corrosive liquids is perforated by a centrally positioned, oblong hole. As known to the art a diaphragm valve for corrosive liquids contains a thin Teflon-diaphragm in contact with the liquid, and a thicker backing diaphragm of rubber or the like serving as a cushion. Both diaphragms are in close contact and are attached to a compressor by a stud bolt which is secured in the compressor by a bayonet closure comprising a cross pin in the top end of the stud bolt which is enclosed in a recess inside the compressor. In a known manner, during fitting of a new backing diaphragm the cross pin is inserted into the recess through a slot and rotated about an angle of 90 degrees. The oblong hole facilitates exchanging the backing diaphragm only without having to withdraw the cross pin out of the bolt, which is usually firmly retained therein by rust or dirt, by pushing the cross pin through the oblong hole and inserting it into the compressor. The diaphragms are subsequently clamped between the valve body and the bonnet. |
