A telescoping hydraulic system is an essential component of a Tower Crane. It allows the crane to extend and retract its boom, enabling it to reach different heights and distances. This system consists of several hydraulic cylinders, valves, and hoses that work together to provide the necessary power and control.
The main hydraulic cylinder in the telescoping system is responsible for extending and retracting the boom. It is typically a double-acting cylinder, meaning it can generate force in both directions. This cylinder is connected to the base of the crane and extends vertically to support the boom. Hydraulic Pump Station,Telescoping Cage,Tower Crane Cylinder,Axial Plunger Pump,hydraulic pump unit SHEN YANG BAOQUAN BUSINESS CO., LTD , https://www.sczenghui.com
To control the movement of the hydraulic cylinder, various valves are used. These valves regulate the flow of hydraulic fluid into and out of the cylinder, allowing for precise control of the boom's extension and retraction. The valves are typically operated by the crane operator using a control panel or joystick.
The hydraulic system also includes hoses that connect the cylinders and valves. These hoses transport the hydraulic fluid, which is typically oil, between the different components. The hoses must be durable and able to withstand high pressure to ensure the safe and efficient operation of the crane.
In addition to the main hydraulic cylinder, there may be secondary cylinders in the telescoping system that provide additional support and stability to the boom. These cylinders are typically smaller and are used to fine-tune the position and angle of the boom.
Shut-off valve how to choose?
In demanding applications will put forward the cut-off valve requirements, so the cut-off valve is an important function and use of internal quality indicators (cut-level classification and standards, see the relevant information). In the field of use, often there will be a good cut off the control valve, leakage and other failures. In addition to plugging, allowing the pressure is too small to be open and other causes caused by increased leakage, the vast majority are due to the structural defects of the control valve and the selection caused by improper. Structural type of choice In cutting effect, the angular stroke valve than the straight stroke valve (such as single-seat valve, sleeve valve, gate valve, etc.) structure is more simple, more reliable sealing, more superiority. More representative of three eccentric hard seal butterfly valve, ball valve and so on. The choice of sealing surface 1) face to face seal: Common plunger plug, the sealing surface is 60 ° cone, the width of this cone is usually between 0.5mm ~ 2mm, to be sealed, we must ensure that two Cone good contact. However, in fact, it is always affected by machining errors (concentricity, out-of-roundness, inclination, etc.) and its sealing effect is not very satisfactory. Leakage rate of such valves is usually 10-4, after precision grinding up to 10-6, up to a higher level of sealing. 2) The spherical seal uses the spherical surface rotation of the spherical surface to be tangent to the fixed valve fixed small cone surface, and they are in line contact with each other, which is more effective than the face-to-surface sealing described above. Ball valve, spherical sealing butterfly valve is to use this idea to produce, the leakage rate of up to 10-6 ~ 10-8, high performance of the three eccentric butterfly valve up to 10-8, or even zero leakage. Selection of Sealing Materials 1) Soft Seals In addition to corrosion-resistant lining valves, the usual soft-sealing valve is either a valve core or a valve seat that employs a valve in the form of a seal of a metallic material (mainly PTFE and rubber, etc.) . Soft sealing valve sealing the best, but in the pipeline installation, cleaning the system may leave more or less clean debris (such as welding slag, iron filings, etc.), they flow through the control valve, easy to put Soft seal seat or spool scratches, so that increased leakage, sealing reliability is poor. Therefore, the choice of soft seal structure must consider the media cleaning and rigorous flushing pipeline before commissioning. 2) Hard Seals Hard Seals Re-surfacing wear resistant alloys are the best choice for shut-off valves. This approach takes into account the sealing of the same time, but also consider the service life and reliability, although the factory index of only 10-4 ~ 10-5, the effect of soft seal zero leakage, but sufficient to meet the strict cut-off requirements, and it Durable, from an economic point of view more cost-effective. Shut-off valve reliability 1) soft seal, cut off well, but not suitable for granular media, once scratched, the leak will increase dramatically. Therefore, when possible, try to use hard seal. "O" ball valve seal up to 10-5 hard, three eccentric butterfly valve up to zero leakage. 2) Consideration of the seal wear resistance: In addition to the selection of hard seal, the leakage of more than 10-4 cut-off regulatory valve must be surfacing wear-resistant alloy to improve seal wear resistance, erosion resistance, scratch resistance The ability to improve valve life. 3) cut off the high temperature medium Regulating valve assembled at room temperature, working at high temperatures, temperature changes of several hundred degrees. Thermal expansion changes the seal's specific pressure at assembly. Too tight, the sealing surface will be card letter, exercise will be serious injury, strain; too loose, the pressure is not enough, the two cases of leakage will increase dramatically. The best solution is to use flexible seat to absorb the changes caused by this difference. There are usually three kinds of flexible solutions: ①spring type; ② sheet flexible metal ring; ③ flexible and flexible valve seat. The latter is the best, both flexible to overcome thermal expansion, but also stiffness and wear-resistant alloy surfacing to improve the reliability of wear-resistant surface. 4) For abrasive media containing particles, consider the direct erosion of the spool away from high-speed media. 5) For the hard seal, there must be sufficient hardness difference, the same hardness material "mutually exclusive", it is easy to scratch and cause leakage. Shut-off valve main valve options As mentioned above, the main valve shut-off valve is as follows, select the shut-off valve should be taken into account the leakage rate, medium type, medium temperature, flow coefficient and other parameters and cost. In the following preferred sequence, consider the first hard seal, and then consider the soft seal. 1) Three eccentric metal seal butterfly valve 2) double eccentric spherical sealing butterfly valve 3) ball valve 4) eccentric rotary valve 5) single seat valve 6) sleeve valve 7) soft seal valve Keywords: Shut-off valve