The conveying technology basically distinguishes between two different processes. The decision is taken on the basis of the respective application, based on your individual needs and expectations.
Dense phase conveying with conventional conveyor lines or the unique DenseFlow Pipe System (DFS)
Dilute phase conveying with injectors and butterfly valves
Either system may be the system of choice and have its respective benefits. Often some combination of the two technologies is needed to arrive at an optimal solutionconveying technology basically.
Dense phase conveying
Dense phase conveying systems are fitted with:
- Pressure vessel
- Rail wagon containers
- Truck containers
As a standard, the pressure vessel operates at a pressure of up to 6 bar(ü), covering conveying distances of more than 1000 m or conveying rates of up to 300 t/.
The conventional cement unloading from rail wagons or trucks is based on the dense phase conveying technology. The bulk material, the condition of the wagon as well as the operating pressure are the factors that determine the conveying rate and the conveying distance.
Dilute phase conveying
This technology is mainly used for continuous transportation with low conveying rates over short distances. The injection of adsorbents into the flue gas treatment process or the feeding of fuel into the incinerator installations are typical examples of this technology.
The bulk material is fed into the conveying line by means of a rotary vane feeder, a butterfly valve or an injector.
Comparison Dense phase conveying / Dilute phase conveying
|Designation||Unit||Dense phase conveying||Dilute phase conveying|
|Conveying pressure||bar ü||high||low|
|Quantity of air / air consumption||Nm3/h||low||high|
|Loading (bulk material/air)||kg/kg||high||low|
|Plant / product wear||low||high|
|Conveying distances||m||up to 2000||up to 250|
|Continuous conveying||Poss. with additional equipment||yes|
|Discontinuous conveying (batch operation)||yes||yes, possible|
|Depending on the bulk material||exclusively||limited|
Conveying with air slides
Air slides involve another tried-and tested pneumatic conveyor system that is normally used for large mass flows.
The bulk solids are fluidised and thus made free-flowing, and gravity does the rest. That means that an appropriate slope must in each case exist between the location of the product and its intended destination.
The functionality is based on the movement of an endless chain that is driven in a trough by an interlocked transmission chain. In addition to its use as a horizontal conveyor up to a length of 40 meters, chain conveyors are also used as slope conveyors and ve
- Horizontal up to a slope of 25 degrees
- Slope angles from 25 to 90 degrees
- Conveyance heights up to 30m
- Deployed as conveying, discharging or distribution unit in bunkers
Sketches for examples of use
The rugged device is deployed as conveying, discharging or distribution unit. In the case of horizontal conveyors using intermediate troughs, as many loading and discharging points as desired can be arranged, which makes this system extremely flexible.
PLACEHOLDER: [Examples of use]
Advantages of the chain conveyor:
- Closed and dust-tight construction
- Suitable for bulk solids at high temperatures
- Can be used for bulk materials that abrade
- Construction is to a large extent self-supporting
- Explosion-proof (conforming with ATEX)
Other mechanical conveying units
We have acquired specific knowledge of discharging from and deploying pipe and trough feed screws, bucket conveyors and conveyor belts. Such equipment is used whenever it can contribute to an optimal overall solution.
- Trough feed screws
- Pipe feed screws
- Bucket conveyors
- Conveyor belts
- Tube chain conveyor
- Vibrating conveyor channel
- and many more
The storage of bulk materials in silos and bunkers requires individual and mature discharging systems. The bulk material concerned predetermines the technology to be deployed.
Sliding frame-thrust plate carrier
This technology is deployed in round silos with flat bottoms, or if the bulk materials to be conveyed has very poor flow properties and large bridging diameters.
Large variety of products
It is however also used in applications in which a large variety of products is expected to be in the same silo.
Rectangular, large surface-area bunkers
The transmission of thrust plate carrier discharge for bunkers works on the same basis, but is deployed especially for the emptying of rectangular, large surface-area bunkers.
Chain conveyors are also a tried and tested technology for discharging from silos and bunkers.
This discharging system is deployed particularly for slow-flowing products and for sludge.
The main advantage of this design is the longitudinal slot shape that results from it, and that the drawing-off can be varied and metered.
Pneumatic discharging aids
The same principle applies here that different systems are installed for different productsjets, fluidsel.
Valve or triple jets, fluidised lava or fluidised streams
Fluidised jets in different versions are deployed as valve jets or triple jets, but fluidised lava or fluidised streams are also deployed in silos with cones or flat-surface floors and for bulk materials that can be more or less easily fluidised.
Service and retrofitting
According to the version in use, service and retrofitting are likewise possible from the outside.
For the transport of bulk materials, silos by rail or by silo trucks are used. Trucks are deployed for local delivery to customers. Transhipment facilities with appropriate storage capacities are the link between them.
Simple handling – great efficiency and safety
STAG is a leader when it comes to transhipment and rail unloading facilities, having constructed more than 40 such plants. Simple handling, combined with great efficiency and operational safety, are the main feature of these STAG plants.
- Cement, lime, gypsum, salt
- Fly ash
- Terephtalic acid
- other bulk products
Simple handling – improved conveying performance – reduced energy consumption
These systems simplify the handling but also reduce the need for manpower. Used in combination with STAG’s DenseFlow Pipe System, conveying performances are improved, energy consumption is reduced and operational safety is enhanced.
Re-development of the rail car
The new rail car “Uacns” represents the latest joint project development. Not only has the discharging mechanism been redeveloped but there is also now a fully automated pneumatic closure "Automatic Hatch" as a replacement for manual dome covers.l.
- Automation of the dome closure for a fully automatic loading of silo rail cars and silo trucks
- Accident prevention - The possibility of remote silo servicing means it is no longer necessary for a man to climb up on to the rail car or truck, thus eliminating the danger of him falling, especially in bad weather conditions and in the winter.
Lump breaker KBT
STAG’s lump breaker is a high-grade quality product, which is deployed principally in the chemical industry and in applications where the requirements for the unit are high.
Single or double-face lump breaker
A single or double-face lump breaker is deployed, according to individual requirements and the throughput capacity.
Impact mill PMS
STAG’s impact mill has been specially developed for the treatment of boiler ash from combined heating and power stations, and for the ensuing pneumatic conveyance of loading into silos.
By using the impact mill the ash arising is treated in such a way that it cannot lead to any functional disturbances in its subsequent pneumatic movement, when being discharged from the silo, or in any truck unloading procedure that may be necessary.