Polyurethane duct insulation board is also a kind of polyurethane "sandwich board", the outer surface of which is about 0.66mm aluminum foil, and the middle is 2.5cm polyurethane hard foam. The production process is similar to the previous "sandwich board" production line, except that it is relatively simple before foaming, there is no unwinding roller, etc., but there are rolled aluminum foils on the top and bottom, and the polyurethane is poured onto the plane running the lower aluminum foil. When the foam is to be foamed, the upper aluminum foil is composited.
It is worth noting that the polyurethane duct insulation board has high requirements on polyurethane. One is the oxygen index of more than 32 and the smoke density of less than 70. Such high flame retardant requirements have greatly limited its large-scale use. Most of these products do not meet the flame retardant requirements. Many domestic manufacturers are quietly reducing the flame retardant standard and entering the market. Second, the foaming parameters of polyurethane are required to be harsh, otherwise it is very easy to appear defective plates, such as plates. There are pits, grooves and blister on the surface, and the polyurethane is required to be solidified quickly. There is no deformation after the ripening stage, otherwise the surface of the finished board will be distorted. Good products should look like mirrors, and some defects are obvious. In addition, the foam should have a certain flexibility so as not to be broken when making the air duct.
Mechanical pumps may be submerged in the fluid they are pumping or be placed external to the fluid.
Pumps can be classified by their method of displacement into positive displacement pumps, impulse pumps, velocity pumps, gravity pumps, steam pumps and valveless pumps. There are two basic types of pumps: positive displacement and centrifugal. Although axial-flow pumps are frequently classified as a separate type, they have essentially the same operating principles as centrifugal pumps.
QFAP has specialize in producing pump housings more than 5years.
Materials: Ductile iron, Grey iron, Aluminum
Surface treatment: Painting, Powder coating, only oiled
Main of our customers is from German, USA, and CAN.
With the long terms of experience in the pump industry, we could supply the pump housings or help to design the housings according to your requirements.
Pump Housing,Pool Pump Housing,Pump Housing Cover,Water Pump Housing Replacement
SHAOXING QIFENG AUTO PARTS CO., LTD. , https://www.sxqfap.com