Concrete Spraying Lance Pneumatic Conveying and Mixing
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Solution Overview
Problem
Existing concrete spraying systems for blast furnace runners are labor-intensive, require multiple personnel, generate significant concrete waste, and involve high water consumption due to the need for wet concrete mixes, leading to increased equipment complexity and downtime.
Innovation Solution
A device with a lance that introduces water and binder late in the process, allowing for a dry concrete mix to be used, which is pneumatically conveyed and sprayed using an annular air flow, reducing the need for large equipment and personnel, and minimizing water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wet concrete mix is used for spraying, then the concrete has good flowability and can be pumped, but the equipment becomes heavy and requires multiple personnel to operate
Solution Approach 1:
The concrete mix is prepared in advance in a dry state and pneumatically conveyed to the application point. Water is then added at the lance during spraying, allowing the concrete to become workable only when needed, thus avoiding the need to transport heavy wet concrete mix
Solution Approach 2:
The concrete mix components (dry concrete, water, binder) are separated and delivered independently. The dry concrete is pneumatically conveyed through lightweight hoses, while water and binder are added separately at the lance, dividing the heavy wet mix into manageable separate streams
2Ease of operation
If wet concrete mix is used, then the concrete can be pumped and delivered, but water consumption for cleaning increases significantly
Solution Approach 1:
The mechanical pumping system is replaced with a pneumatic conveying system that delivers dry concrete mix. This eliminates the need for water-based cleaning of pumps and mixing equipment, as the dry material can be blown out with compressed air, dramatically reducing water consumption
3Productivity
If wet concrete mix is used, then the concrete can be sprayed effectively, but concrete loss during cleaning becomes significant
Solution Approach 1:
Compressed air is used instead of water for cleaning the lance and delivery system. The dry concrete mix can be easily blown out through the same pneumatic conveying system, eliminating the need to dispose of water-concrete slurry and reducing concrete waste
Solution Approach 2:
The system is designed for easy disposal of residual dry concrete through pneumatic blowing, and the lightweight equipment can be quickly moved or replaced, minimizing the amount of concrete that becomes waste material
4Ease of operation
If complex equipment with multiple components is used, then the concrete can be pumped and sprayed, but the equipment complexity and personnel requirements increase
Solution Approach 1:
The pneumatic conveying system combines material transport, mixing (by adding water and binder at the lance), and spraying delivery into a single integrated system. The lance itself performs multiple functions: receiving dry concrete, adding water and binder, and spraying the mixture, eliminating the need for separate pumps, mixers, and delivery hoses
Solution Approach 2:
The lance serves multiple functions: it acts as the receiving point for pneumatic concrete delivery, the mixing chamber where water and binder are added, and the spraying nozzle. This multi-functional design eliminates the need for separate specialized equipment for each function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device enables one-person operation, reduces concrete waste, lowers water consumption, and decreases equipment complexity, resulting in faster repairs and reduced blast furnace downtime.
Implementation Method 1
an air supply which is located on the lance at a distance from the binder supply. The air supply is set up and designed to generate an air flow that is directed into the material flow via annularly arranged nozzles, at least partially radially oriented. This air flow is, in particular, compressed air, which is controlled by the operator to achieve the optimal spraying result, in particular to accelerate the material before it exits the connected lance nozzle.
Implementation Method 2
The water supply is set up and designed to introduce water into the lance so that the dry concrete mix mixes with the water in the lance and the flowability of the concrete in the lance is increased.
Implementation Method 3
A dry refractory mass can therefore be used as the concrete mix, which is usually transported using a pneumatic conveyor. It is not absolutely necessary to use a completely dry refractory mass. It is sufficient to use a relatively dry or only slightly moist concrete mix. This relatively dry concrete mix, which will subsequently be referred to as dry concrete, is transported by air from the pneumatic conveying source towards the lance.
Data Source
Figure 1
Figure 2
AI summary
The present application relates to a device 1 for spraying concrete, comprising the following features: a) a conveying line 2, which is configured and designed to receive concrete from an inlet end 5 and convey it to its other outlet end 6; b) a lance 13, which is configured and designed to discharge the concrete by spraying; c) the lance 13 has an inlet end for the concrete supplied by the conveying line 2 and a water supply 7 adjacent to this inlet end, wherein the water supply 7 is configured and designed to introduce water into the lance 13, so that the concrete mixes with the water in the lance 13 and the flowability of the concrete within the lance 13 is increased;f) In the direction of flow of the concrete, at a distance from the water supply 7, a binder supply 9 is connected to the lance 13, the binder supply 9 being configured and designed to introduce a binder into the water-enriched concrete; g) at a distance from the binder supply 9, an air supply 11 is connected to the lance 13, which is configured and designed to form an annular airflow 12 that determines the size of a spray cone of the concrete exiting the lance 13.