Bridge cranes come in two basic designs and these include the single girder crane and the double girder gantry crane. Professionals in the industry will refer to these as 1 cross girders or 2 cross girders. No matter what they are called, when you need to buy one for your facility, you probably just want to know the answer to one question. Which one do you choose?
To answer that question, you should learn about the basic differences between them. The differences can help you to see why one would benefit you more than the other.
They are both equally strong, durable and rigid. Some people are under the assumption that the single girders would be less strong but that is not true. Both perform their own functions differently but they both are strong.
A single crane has lateral bracing which a double girder does not have. It also has stronger girders for greater reinforcement.
The double has a higher hook height. This is where you may find that your applications will do best with this crane rather than the single. The hook height is about 18 to 36 inches higher than that on the single girder gantry crane. If your jobs require items being lifted from greater heights off the floor, this is the crane for you.
Double girder cranes are able to provide a higher lift because also because the hoist is in between the cross girder. With a single girder crane, the hoist is located under the cross girder and it cannot provide much height.
As to choosing which crane is best based upon the weight, it can lift, a single crane will lift up to 50 tons. It is best for the light lifting of about 20 tons to be on the safe side. The span can only be 35 meters for the space needed for the crane. If your job requires wide leg widths, fast working speed and lots of heavy lifting, choose the double girder instead.
Operating times for the single crane should not go beyond six hours. If you need to run the crane eight hours or more, choose the double crane.
Single cranes are less expensive than the other mostly because of their design and because they cost less to ship. If you need a specialty item, it may cost more even if it is a single but remember those good manufacturers will work with you to help you find the most economical choice. Even if it costs a little more, it is going to help your company’s productivity, so think of it as an investment that will end up paying for itself.
There are two options that you have for overhead gantry cranes. Now that you know the differences, you should be able to make a choice. Take into account all the needs your company has for lifting, how often the crane will operate and what your budget is. With the help of a crane manufacturer representative, you will be able to find the right model to meet these objectives for you.
Useful reference: https://dafanggantrycrane.com/double-girder-gantry-crane/.