Vertical drying cylinder drying machine is mainly composed of column, drying cylinder, bearing and sealing parts, water trap, steam inlet and drainage pipe, expanding device and transmission device.
Dryer is heated by steam. The steam is passed into the hollow column (or the steam pipe next to the trough rectangular column) of the dryer by the steam main pipe, and is respectively introduced into each drying cylinder. Each inlet column (or inlet pipe) are equipped with a regulating valve, a safety valve and a pressure gauge, when the steam pressure on the unit area exceeds the specified pressure, the safety valve will automatically open, release the overpressure of steam. The steam entering the drying drum transfers the heat to the drying drum, and then transfers the heat from the surface of the drying drum to the water-containing fabric around the surface of the drying drum. The steam condenses into water due to the loss of heat. The condensed water is discharged from the drying drum by the drainage bucket or siphon, enters the column at the drainage end (or the outlet pipe), and is discharged out of the machine through the hydrotrap. Water and steam are prevented from escaping at the same time by the action of the trap.
Drying drum Drying machine is the main part of the drying drum, drum bearing and three parts of the trap.
1. Drying cylinder
Drying drum is one of the main parts of drying drum drying machine. The diameter can be divided into 570mm or 800mm, and the working range is 1000mm-4400mm. The wrapping Angle of the fabric on the drying drum is 250° ~ 276°. According to the different heating methods, the drying drum can be divided into two categories: steam heating type drying drum and heat conduction oil heating type drying drum.
2. Drying cylinder bearing and close cutting parts
In addition to supporting the drying drum, the drying drum bearing must also play a sealing role on the steam introduced into the drying drum or the condensed water discharged outside the drying drum. At present, there are three types of packing close cutting, plane close cutting and spherical close cutting.
(1) Packed sealed drying cylinder bearings: as shown in Fig. 5-10. The steam enters directly into the inner hole of the drying drum shaft head through the steam inlet hole of the bearing seat. Adjust the pressing screw, through the lambing pressing the spiral asbestos rubber packing, the formation of radial contraction, well and shaft head to form a rotating cylindrical close cut. This kind of close cutting on the drying cylinder shaft head rotation resistance is large, easy to wear, increase the transmission power consumption. But because of its simple structure, processing, maintenance and repair are more convenient, installation requirements electricity is not high, therefore, although relatively old, is still in use.
(2) Plane dense cutting drying cylinder bearing: Figure 5-11 shows the end face dense cutting using solid lubrication materials. Its main feature is to change the support of the drying cylinder shaft head from the front sliding bearing to the rolling bearing, which reduces friction and improves transmission efficiency. The rotary seal adopts the close cut form of the end face of plastic graphite die casting. Use a siphon to remove condensed water.
The steam from the steam lambing by spring pressure into the drying cylinder shaft head hole. Rotational close cutting is mainly formed between the plastic graphite die casting and the two end faces of the sealing ring, and the spring presses them closely. The circular rubber close cutting ring makes the casting plastic parts and the inlet steam head shell close cutting, and makes it not rotate with the shaft head. The other cylindrical close cutting ring makes the close cutting ring and the shaft head sealed, and makes it rotate with the shaft head. The rotating close cutting ring is used to prevent the lubricating grease of rolling bearings from spillage.
Fig. 5-12 shows another structure of planar dense - cut cylinder bearing. Its sealing mainly depends on the spring and pressure ring, pressing the plane close cutting ring, so that it is close to the end face of the shaft and the formation of close cutting. The function of the annular close cutting ring is to prevent the leakage of steam from the outer circle of the steam pipe. This kind of planar dense cutting structure has good sealing performance, long service life, less rotating power consumption, and is not easy to be worn. At present, the water bucket drying drum generally adopts this kind of close cutting form.
(3) Spherical close-cut cylinder bearing: as shown in Fig. 5-13, it is installed outside the rolling bearing of the cylinder, and the sealing pipe and the shaft head of the cylinder are closely connected by threads. The steam from the intake steam through the sealing pipe into the inner hole of the drying cylinder shaft head into the drying cylinder, the rotation of the close cutting is by the spherical friction between the fixed spherical close cutting ring and the close cutting ring, sealing pipe to achieve. The spring compresses the friction spheres without leakage of steam. The condensed water is discharged from the siphon through the outlet elbow.
3. Hydrophobic device
The trap is commonly known as the steam back 甏, also known as the steam drain valve. Its purpose is to prevent steam leakage, reduce heat loss and improve heat transfer efficiency while removing condensate water. There are many kinds of traps. There are three kinds of commonly used buoy type hydrotrap, bell - shaped float type hydrotrap and eccentric thermodynamic hydrotrap.
(1) Working principle:
① Working principle of buoy type hydrotrap: The structure of buoy type hydrotrap is shown in Figure 5-14. Figure 5-15 is a schematic of how it works. When condensate water and some steam enter the trap, the buoy rises due to the buoyancy of the water, and the cut-off valve closes to prevent the steam leakage, as shown in Figure 5-15 (a). With the continuous inflow of condensed water, the water level will gradually rise. When the liquid level rises to a certain height, it will overflow into the buoy, as shown in Figure 5-15 (b). When the weight of condensed water in the buoy exceeds the buoyancy force received by the buoy, make the buoy sink, open the globe valve, and the condensed water in the buoy is discharged through the sleeve, globe valve and regulating valve under the steam pressure, as shown in Figure 5-15 (c). When a certain amount of condensed water is discharged, the buoyancy makes the buoy rise again and the stop valve is closed. The condensed water flows into the tank continuously and the second cycle is carried out. Because there is always some condensed water in the buoy, and the water level is higher than the lower end of the casing, the water cut is formed, and the steam can not leak out. Regulating valve is used to adjust the water flow rate when drainage, so that the buoy slowly rise, to avoid a strong blow.
Some traps are equipped with a straight-through valve near the regulating valve to release air and discharge condensed water when driving. An observation valve is installed at B to check the working condition of the trap. When the valve is unscrewed, it can intermittently eject condensed water, then it works normally: if there is a large number of steam continuous leakage, the working condition is not good, it should be adjusted or repaired in time.
The trap has reliable construction, almost no steam leakage, and does not require a double filter. But the volume is large and ponderous, belong to intermittent drainage.
② The working principle of bell shaped float type hydrotrap: Figure 5-16 shows the bell shaped float type hydrotrap, which is composed of a shell, an upper cover, a valve, a metal double spring plate, a bucket (bell shaped float) and a connecting rod. This kind of trap is the use of metal spring plate hot bending characteristics to prevent steam drainage.
When some steam and condensed water enter the trap through the strainer at the bottom of the trap, the bucket floats because of the steam pressure, and the valve disc is driven through the connecting rod to close the valve seat and prevent the steam leakage. At the same time, because the temperature in the bucket rises, the spring sheet is heated and the cover of the end of the spring sheet is elongated.
