Drainage varying
1. Need to maintain uniform stock temperature. — increasing temperature of stock improves drainage. — higher stock temperatures can adversely affect other properties. 2. Check system for surfactants and foaming. (See Foam control.) — surfactants can improve water removal rate but excess will create its own stable foam. — entrained air greatly reduces drainage rate. […]
Couch vacuum varying
1. First, it must be determined whether the source vacuum or sheet resistance is changing. 2. Check vacuum pumps and seal water, and check for slipping belts. 3. Check that consistency of mixed stock is steady. 4. Examine the basis weight profile. — is it steady with time? 5. Check total head in headbox for […]