First, be clear of your demand. The best crane is not the most expensive one, but the one that meets your demand. Next, keep sober in face of various brands and products. Famous brand and large company usually represent good quality. Such as TICO
. Then, choose a formal and reliable purchasing channel. Factory direct sales and official websites can be a prior choice. Finally, be cautious with your investment. The price of cranes is not a small number. A purchasing decision should be based on your consuming capacity.
Having taken all the factors above into account, here are some parameters of crane you can refer to.
The most common lifting capacity of bridge crane is 5t, 10t, 16t, 20t, 32t and 50t. You can choose one specification according to the heaviest mass it may hoist. For overload is forbidden, you’d better choose those with larger capacities.
According to their working frequency and loading rates, bridge cranes are universally divided into 8 classification groups, from A1 to A8. During the lifetime of a crane, its total working cycle is finite. The number of working cycle indicates the degree of its utilization. Higher classification group cranes bear more working cycles. To use cranes in a scientific and economical way, we’d better choose the classification grade suitable for the working condition and intensity.
The concept of working speed contains the lifting speed, the running speed of trolley and trunk. Working speed mainly depends on the lifting weight and classification grade. This means high speed crane apply to middle and light weight, while heavy weight suits lower speed. Similarly, higher working intensity and efficiency require higher speed and vice versa. In addition, to undertake a lot of transfer work, high speed is indispensable. As for maintenance work, adjustable speed is a better choice. Cranes with large lifting height can adopt low speed in loading heavy weight and high speed in no-load conditions.
Span refers to the horizontal distance between the rails where bridge crane running. Crane spans depend on the width of the plants where bridge cranes is used. Generally, the span grade is classified every 3 meters. Cranes under the lifting weight of 50t are classified into two categories. The little ones apply to plants in the center of which remains escape ways. When cranes weighting over 80t and under 50t runs in the same rail, the span depends on the heavier one.
The concept of configuration includes span structure, trolley, control mode and loading handling devices. A proper configuration fit cranes to various conditions.
Single and double girder bridge cranes are the major categories of bridge cranes. Single girder bridge cranes apply to such situations: the lifting weight is under 10t, the working intensity is low and the span is short. With electric hoist serving as lifting component, this type of crane boasts its compact structure, low price and lighter weights. As for other situations, double girder bridge cranes are better choices. They have advantages in stable structure, large bearing capacity and higher performance. To adapt to different situations, manufacturers also provide customized scenarios.
As an important part of cranes, trolley can travel on the cranes and hoist weights. Double girder bridge crane usually adopts upper lifting trolley. It has larger loading capacity and more stability, but looks bulky. Therefore, electric hoist is an ideal substitute, which is more compact and lighter. Single girder crane usually has a electric hoist hanging under it. This is a light and handy structure, but the hoist under the girder will shorten the hoist height. To solve this problem, there emerges another type of single girder crane, having the electric hoist on one side. But it needs a balanced weight on the other side, which increase its self weight.
To operate large scale, high grade and high speed cranes, cab manipulation is a secure way. Cabs are usually attached to one side of the bridges. In face of long spans and complex conditions, we can move cabs along with hoist trolleys. It will be more convenient if cabs can move along the girders.
Ground control applies to the following conditions: the working speed is low and the distance is short, drivers are supposed to hang and take off hooks in flesh, the plant is too small or the ground equipment is too high to install a cab, or the upper places are filled with toxic gases. The working speed of ground control crane is less than 45meter per minute. In recent years, wireless remote control has become increasingly prevalent.
Loading handling device
Suitable handling devices is of great significance for security and productivity. To handle cargos of various shapes, cranes are equipped with hooks, grab buckets, electromagnetic chucks and grippers, etc.
Hooks are widely adopted by cranes, grab buckets are mainly used for particle materials, and electromagnetic chucks apply to magnetic metal materials. Different varieties of material and high productivities require double-purpose bridge crane equipped with 2 kinds of loading handling devices. Two set of lifting mechanism installed in the trolley can work separately.
To adapt to special environments and specific working conditions, cranes must meet such particular requirement as automatic control and security protection.
Generally, bridge crane can work within the temperature from -25℃ to 40℃. In low temperature environments, warm driver cab and cold-resistant metal are indispensable. In high temperature environments, there should be thermal insulation layers and cooling mechanism for electric devices. For outdoor usage, rain cover is necessary for trolley, traveling mechanism and electrical devices. In smelting industries, relative parts in the cranes must be insulating so as to work in electronic tanks. In the presence of corrosive medium, cranes have to adopt corrosion-resistant steels or coatings.
As experts predicts, 20% to 30% of bridge cranes will be equipped with automatic systems in the future. To carry cargos accurately, we should choose automatic cranes with anti-swing lifting slings. To handle nuclear fuels and install precise instruments, we’d better consider cranes with accurate positioning ability. To ensure the working security, we ought to adopt cranes with fault diagnosis and monitoring systems.
Different protection devices are needed to ensure working security in various conditions. For example, adding overload limiter to those likely to overload, anti-crash device to cranes working in the same span, wind-proof device to outdoor cranes, lubrication system to those frequently loading heavy weights, anti-meandering equipment to those running on long spans, etc. When handling dangerous goods, we can adopt fault protection system, where one can undertake the whole work when the other has broken down. Here are a few indicators you can refer to when purchasing: the average working time before the first trouble, equivalent average trouble-free working hours, mean time to repair and operational availability.
To protect drivers and improve working efficiency, we should make sure they have good sights and favorable environments. The operating devices should be properly distributed. To reduce the impacts from bridge vibration, we can choose cabs with vibration isolation devices. Other ergonomically designed instruments inside are also essential.
As researches indicates, harmonious color scheme can please operators so as to reduce their fault and improve their efficiency. The colors of cranes are required to be coordinated with surroundings and keep conspicuous at the same time.
When used in middle-sized plants or warehouses, light and simplified cranes are prior choices. Like electrical hoists or light bridge cranes, such types of cranes can help reduce cost and running power.
The price of a crane covers the purchasing cost as well as the cost of using them, including operation, maintenance and spare parts. We should also take into account the production loss arising from crane breakdowns. Therefore, the performance and reliability of a crane are also components of its price.