Before you can decide between a single girder crane or a double girder crane, you need to know what they are all about. This guide will help explain what bridge cranes are and which ones are suited best for your use even if you are entirely new to the subject.
A bridge crane is more professionally known as an overhead crane. This type of crane is often used in an industrial environment where lifting of heavy objects is required. In an overhead crane you will see parallel runways that are attached to a travelling bridge spanning the entirety of the gap. A hoist is attached to the bridge and is the major lifting component of an overhead crane. The hoist is what hooks the freight and moves it along with the help of the bridge.
As per the Crane Manufacturers Association of America (CMAA) bridge cranes are manufactured with two designs. A single girder and a double girder known as 1 or 2 cross girders in crane manufacturers’ language. You have two main options to choose from when you go about buying a bridge crane; namely single girder or a double girder crane. What you need depends upon the particular need for which you are buying a crane in the first place. However consider that buying cranes is not an everyday business but in fact a once in a lifetime investment, you need to be very certain about the type of crane you purchase.
Both single girder and double girder cranes are equally strong, rigid and also durable. There are misconceptions about the single girder cranes being less strong and durable as compared to a double girder but that is certainly not the case. Both cranes have different functions and different needs that they serve. Below explained are two major differences between single girder and double girder cranes so that you can make an informed decision about which one will serve the best purpose to you.
- A single girder crane is known for its lateral bracing which is absent in a double girder crane. Also a single girder crane has stronger cross girders allowing for better reinforcement in tasks where reinforcement is needed with a crane.
- As compared to a single girder crane, a double girder crane has a much higher height of the hook. It is usually about 18-36 inches higher than a single girder crane. Greater hook height is needed when you need to lift things at a greater height from the floor. This is one of the major advantages that a double girder crane has over a single girder.
- A double girder crane is able to provide a higher lift because its hoist is situated between the cross girder. A single girder crane has its hoist placed under the cross girder and thus cannot provide much height.
Another very specific and important difference between a single girder crane and a double girder crane is that of its price. Single girder cranes are more affordable as compared to a double girder crane. This is because a single girder crane has just one cross girder and the design of the trolley is simple as compared to the other. Also the freight for a single girder crane is lesser thus the low price.
Not all cranes are single girder cranes. Single girder cranes span about a 100 feet and have lifting capacities for weights up to 100 tons. As per CMAA and cost effective studies, single girder cranes are considered as per the table mentioned below:
|Capacity (Tons)||Maximum Span (Feet)|
Usually double girder cranes that are available in the market have very hoist and its trolley on top of cross girders. There is a space for a trolley with low headroom to be created and situated between the cross girders. This low trolley will be very beneficial if the crane requires maximum hook height, if the cross girder and the hoist is situated at a maximum height above the floor and also when distance minimizing is needed between the runway beams.
Here is an overview of a single girder crane and a double girder crane which will allow you to make your choice easily:
Single Girder Crane
- One girder/can only operate in single direction
- The structure is small, single hoist, single girder, end girders, electrical controls, low height, light weight, small size, small wheels
- Cable operation and also wireless remote control options
- Effectively improves utilization of space
- Low plant investment costs
- High end braking system automatic with anti-dust device
Single girder cranes are best when you need to lift weight under about 50 tons and the span is less than 35m. There isn’t any special use or requirements for a single girder crane. If you don’t need wide leg width, a very high working speed along with lifting of heavy things on a frequent basis, a single girder crane would be best suited for your operations.
Double Girder Crane
Double girder cranes are known to be the most important equipment for the mechanization and automation of the production process in the modern industries. Double girder cranes come in very handy during production and transportation of heavy equipment and weight. The double girder crane is used widely for both indoor and outdoor industries. It is also heavily used in mining, railway transportation, steel industry, logistics, port terminal and a lot of other industries and departments.
Double girder cranes are ideal when frequent lifting of heavy loads is required and that too for longer hours. 8 hours being the minimum limit whereas more can be added as per need. A single girder crane is ideal for short operation times; 6 hours being the maximum limit.
The price difference between the two cranes is one of the most sensitive differences there can be. Double girders are more expensive because of their structure and mechanism but both cranes are designed to serve their individual purpose which is suited to the industry.