PVC material used in bathroom drain water system
PVC is an acronym that stands for polyvinyl chloride. Of the different types of plastic pipe used for water supply, PVC has a wide variety of plumbing uses, from drainage pipe to water mains. It is most commonly used for irrigation piping, home, and building supply piping. PVC is also very common in pool and spa systems. PVC pipe is often white but it can also come in other colors. You can often tell what it is used for by the colors and marks on the pipe. For example, a purple pipe with black lettering is used for reclaimed water. PVC also comes in a variety of thicknesses, called schedules. Schedules 40 is the most common for pipes used in water distribution.
Historically, PVC was one of the first forms of plastic used instead of copper for water supply pipes. PVC is normally used for cold water pipes only, as heat can eventually break down the plastic. Always check with local code restrictions before using PVC pipes for hot water delivery lines. In homes plumbed with first-generation plastics, the cold water lines are often PVC, with CPVC used for hot water lines.
PVC connections are made by using a primer that softens the PVC and then applying PVC glue that melts the joints and pipes together. PVC pipe should always be clearly labeled if used for potable (drinkable) and non-potable water in the same building.
Typical applications of PVC material
Water distribution piping, home plumbing, house siding, business machine housings, electronics packaging, medical apparatus, packaging for foodstuffs, etc.
Injection molding process conditions
1. Drying: Not usually necessary as PVC absorbs very little water
2. Melt temperature: 160 - 220 C (320 - 428 F)
3. Mold temperature: 20 - 70 C (68 - 158 F)
4. Material injection pressure: Up to 150 MPa
5. Packing pressure: Up to 100 MPa
6. Injection speed: Relatively slow, to avoid material degradation
Mold runners and gates
All conventional gate types may be used; pin-point and submarine gates are used for molding small components and fan gates are typically used for thick sections. The minimum diameter of pin-point or submarine gates should be 1 mm and the thickness of fan gates should not be less than 1 mm.
Sprues should be as short as possible; typical runner sizes are 6 - 10 mm and should have a full round cross-section. Insulated hot runners and certain types of hot sprue bushings may be used with PVC.