Excavators have become the most important machinery category among numerous construction equipment in project construction. The emergence of hydraulic excavators has provided an advanced and efficient construction method for earthwork projects.
1. Purpose of Excavators
Excavators are primarily used to complete the following tasks:
- Municipal garden construction;
- Excavation of foundations for buildings and factories;
- Excavation of soil, stripping of overburden in mining areas;
- Loading operations in quarries, tunnels, underground factories, and stockyards;
- Excavation of channels, canals, and dredging of waterways;
After changing the working device, it can carry out operations such as crushing, lifting, installation, piling, compaction, and drilling.
2. Purchase Considerations
As one of the most important types of construction machinery in project construction, the correct selection of excavators is especially important. How to properly purchase a hydraulic excavator is determined by many factors, such as the nature of the construction task, scale, technology, cost-effectiveness, equipment that complements it within the construction project, and construction time requirements.
Additionally, the following aspects are very important: mechanical performance, reliability, and durability should be good, and improving comfort and safety is essential. Moreover, good after-sales service can reduce downtime for users and increase economic benefits. Of course, the availability of spare parts and the cost are important factors that must be considered when purchasing equipment.
2.1 Project Scale
Operating conditions and mobility: For large-scale projects with poor working conditions, crawler hydraulic excavators are generally a suitable choice. For construction in small spaces with limited environmental space, tailless compact excavators can be selected.
For general periodic small projects, such as road maintenance, agricultural water conservancy, and municipal gardens, a small model excavator is sufficient. For example, widely used models between 5 to 8 tons can fully meet the requirements. At the same time, a variety of work devices can be ordered to be replaced as needed according to construction requirements, such as quick couplers, hydraulic breakers, vibrating compactors, auger drills, hydraulic shears, and other work devices available for selection.
2.2 Operating Conditions and Construction Mobility
The operating conditions and the mobility of the construction directly affect the selection of the excavator's undercarriage and working equipment.
- Considerations for selecting the undercarriage
The undercarriage of an excavator is generally categorized into three types: crawler, wheeled, and pontoon. Crawler excavators are more commonly used, while wheeled and pontoon excavators are less common.
Crawler Excavators: Characterized by high traction force, low ground pressure (generally 0.04-0.15Mpa), good stability, and excellent off-road and climbing capabilities. They are widely used in poor working conditions, and standard crawler excavators are generally chosen based on ground conditions.
Wheeled Excavators: They are known for high transmission efficiency, fast travel speeds, and good maneuverability, with excellent mobility. They are generally used in better working conditions where the workplace needs to be frequently relocated.
Pontoon Excavators: Generally used for cleaning silt and sediment in riverbeds, rivers, and lakes.
- Considerations for selecting the working equipment
In general, an excavator's working equipment includes the boom, arm, bucket, and related hydraulic cylinders and hydraulic pipelines. Since the working equipment of an excavator can be conveniently replaced, it can be swapped out according to different working conditions to meet the needs of various operations.
For instance, the entire working equipment can be fitted with an extended arm (both the boom and arm are lengthened, and the bucket capacity is reduced), which increases the excavator's digging range, especially suitable for building demolition and river dredging.
As for buckets, depending on the digging conditions, one can choose from a standard bucket for general conditions, a larger bucket for loose materials, a rock bucket for rocky conditions, and a cleaning bucket for dredging. Additionally, the bucket can be replaced with a breaker, which is very useful for breaking concrete and rocks, offering a safer and more efficient alternative to explosive demolition for small-scale work.
The bucket can also be swapped for a grapple, which is useful for handling waste materials, or for a hydraulic shear, which is ideal for demolishing buildings and is a good investment for those involved in municipal engineering.
For special working conditions at construction sites, it may be necessary to consider adding cylinder guards to prevent damage from falling objects or collisions with obstacles; machines working on ships or at floodgates sometimes require the installation of hook devices to facilitate the lifting of vehicles.
2.3 Machine Performance, Reliability, and Durability
The reliability and durability of a machine are crucially dependent on the performance of its main components, such as the engine, hydraulic pump, main control valve, and hydraulic motor. The quality of these components directly affects the lifespan of the excavator.
As the excavator’s power source, the engine requires high power and torque, while also considering environmental protection. Therefore, it is essential to choose a good engine, and engines specially designed and manufactured for construction machinery by world-renowned engine manufacturers are known for their stability and coordination.
Hydraulic components, such as hydraulic pumps, control valves, and hydraulic motors, should also preferably be sourced from world-renowned hydraulic parts manufacturers. Only by doing so can the assembled excavators be durable and long-lasting.
2.4 Comfort and Safety of the Operator's Console
The environment of the cab and the quality of the operating system directly relate to the comfort and safety of the operation, also affecting work efficiency. It is important to check whether the excavator's cab is equipped with shock absorbers, how effective its sealing is; the adjustability and comfort of the seat; whether it is equipped with air conditioning; and if there is an emergency escape device to ensure the safety of the operator at work.
Based on the factors mentioned above, one can generally determine the specifications, quantity, structural form, and working equipment of the excavator to be purchased, and then identify the specific model and manufacturer of the chosen excavator. Through comprehensive analysis of these aspects, buyers will be more rational when selecting an excavator, enabling them to choose the most suitable one from the wide variety of excavator brands available.
