1. Basic structure of single screw pump seal
The seal of the single screw pump is a sealing device composed of two smooth and flat surfaces perpendicular to the axis of rotation. Under the action of the loading device, they are closely fitted to each other and rotate relative to each other. circle composition.
The basic components that constitute the seal of a single screw pump are a moving ring, static ring, moving ring sealing ring, static ring sealing ring, shaft sleeve, gland, spring, etc
2. the role and requirements of the basic components of the single screw pump seal
① End face seal pair (static and dynamic rings).
The function of the end face seal pair is to make the sealing surface closely fit to prevent medium leakage. It requires that the static and dynamic rings have good wear resistance, and the dynamic ring can move flexibly in the axial direction, automatically compensating for the wear of the sealing surface, so that it fits well with the static ring; the static ring has floating properties and acts as a buffer.
For this reason, the sealing surface requires good processing quality to ensure that the sealing pair has good bonding performance.
②Elastic elements (springs, bellows).
It mainly plays the role of compensation and buffering. It is required to maintain enough elasticity to overcome the auxiliary seal, the friction of the transmission part and the inertia of the moving ring, etc., to ensure the good fit of the end face seal pair and the followability of the moving ring. The material requires corrosion resistance. , Fatigue resistance.
③ Auxiliary seals (o-rings, V-rings, U-rings, wedge-shaped rings and special-shaped rings).
It mainly plays the role of sealing the static ring and the moving ring and also plays the role of floating and buffering. It is required that the sealing element of the static ring can ensure the sealing between the static ring and the gland and the floating of the static ring, and the sealing element of the moving ring can ensure the sealing between the moving ring and the shaft or bushing and the stability of the moving ring. floating. Materials are required to be heat-resistant, cold-resistant and compatible with the medium.
④Transmission parts (transmission pins, transmission rings, transmission seats, transmission keys, transmission lugs or jaw couplings).
It plays the role of transmitting the torque of the shaft to the moving ring. The material requires wear and corrosion resistance.
⑤ Fasteners (set screws, spring seats, glands, assembly sleeves, shaft sleeves).
It plays the role of positioning and fastening of the static and dynamic rings. It requires correct axial positioning to ensure a certain amount of spring compression so that the sealing surface of the sealing pair is in the correct position and maintains a good fit.
At the same time, it is required to be easy to disassemble, easy to put in place, and reusable. At the place where it cooperates with the auxiliary seal, the installation seal ring must have a guide chamfer and a spring pressure. Special attention should be paid to the joint between the auxiliary seal of the moving ring and the shaft sleeve, which requires wear resistance and corrosion resistance. If necessary, the joint with the shaft sleeve can be Hard surface cladding.
3. The division of balanced and unbalanced seals
According to the specific pressure unloading caused by the medium pressure on the end surface, it is divided into two types: balanced type and unbalanced type. The one without unloading is called the unbalanced type, the unloaded one is called the balanced type, the part unloaded one is called the partial balanced type, and the unloaded one is called full balanced type.