Rotatable Shaft Metering Apparatus for Precise Powder Delivery
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Solution Overview
Problem
Current metering technologies face challenges in accurately and precisely delivering small quantities of powdered materials, such as 1 to 9 micrograms per second, and larger amounts up to 1000 micrograms per second, without the use of carriers, while maintaining control over dopant and host feed rates in vaporization processes, especially for temperature-sensitive organic materials used in OLED manufacturing.
Innovation Solution
A metering apparatus with a reservoir, a housing having first and second openings, and a rotatable shaft with a circumferential groove that transports particulate material without carriers, allowing for adjustable and controlled delivery of small quantities, including the use of a scraper to dislodge material and ensure uniform vaporization, and a flash evaporator for vaporizing the metered material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional auger design with patterned screw is used to meter powders, then material transport is achieved, but discharge rate varies cyclically and precision is poor
Solution Approach 1:
The auger screw is segmented into distinct functional zones: a transport section with patterned threads for material conveyance, and a smooth-bore section for consolidated material storage and uniform discharge. This segmentation allows each zone to perform its specific function optimally, eliminating the cyclic discharge variation that occurs in traditional uniformly patterned augers.
Solution Approach 2:
The threading pattern is extracted from the discharge section of the auger, creating a smooth-bore terminal end. This removal of the threading pattern from the discharge zone eliminates the source of cyclic discharge variation, allowing material to be discharged uniformly without the periodic disturbances caused by thread engagement and disengagement.
2Productivity
If powder is transported in horizontal orientation, then transport efficiency is improved, but discharge rate varies cyclically with angular orientation
Solution Approach 1:
The auger is divided into a horizontal transport section and a vertical discharge section. The horizontal section maintains transport efficiency by conveying material along the bottom of the auger barrel, while the vertical smooth-bore section ensures precise, non-cyclic discharge by allowing material to fall uniformly under gravity without angular variation.
Solution Approach 2:
The discharge section transitions from horizontal to vertical orientation, changing the dimension of material discharge. This vertical orientation eliminates the angular orientation dependency that causes cyclic discharge variation in horizontal augers, while the smooth-bore design maintains transport efficiency through consolidated material flow.
3Ease of operation
If carrier materials are used to facilitate powder transport, then transport is improved, but system complexity and contamination risk increase
Solution Approach 1:
The auger design enables self-service powder transport through its geometry and material consolidation features. The smooth-bore terminal end and controlled discharge section allow the auger to transport and discharge powder directly without requiring external carrier gases or liquids, eliminating the complexity of carrier addition, removal, and handling systems.
4Productivity
If material is heated to high temperature for vaporization, then vaporization rate increases, but temperature-sensitive organic materials degrade
Solution Approach 1:
The system uses rapid flash vaporization where material is heated to high temperature for a very short duration and then immediately vaporized. This rushing through the high-temperature zone prevents thermal degradation of temperature-sensitive organic materials while achieving high vaporization rates, as the material does not remain at elevated temperature for extended periods.
Solution Approach 2:
The vaporization process uses periodic pulsed heating rather than continuous high-temperature exposure. Material is delivered in controlled amounts and subjected to brief heating cycles that achieve vaporization without sustained thermal stress, preserving material integrity while maintaining productivity.
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
Enables precise and uniform metering and vaporization of small quantities of powdered materials, maintaining the material at room temperature until discharge, allowing for extended operation with reduced risk of degradation, independent control of dopant and host feed rates, and rapid starting/stopping of vaporization, while achieving higher vaporization rates and controlled film thickness.
Implementation Method 1
a rotatable shaft disposed in the internal volume, the shaft having a smooth surface and a circumferential groove aligned with the first and second openings for respectively receiving and discharging the particulate material; the rotatable shaft and the internal volume cooperating such that the particulate material is substantially transported by the circumferential groove and not along the remainder of the rotatable shaft
Implementation Method 2
a scraper disposed in relation to the second opening, having at its end substantially the same cross section as the groove in the rotating shaft, the scraper cooperating with the groove to dislodge particulate material retained therein, and in response to the shaft rotating, delivers metered amounts of particulate material through the second opening
Implementation Method 3
a flash evaporator that receives and vaporizes the metered material
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Apparatus for vaporizing a particulate material, comprising a metering apparatus including: a reservoir (130a); a housing (140) having an internal volume (150) and first and second openings (160) for respectively receiving and discharging the particulate material; a rotatable shaft (170) disposed in the internal volume, the shaft having a smooth surface and a circumferential groove for receiving particulate material from the reservoir and for discharging the particulate material; the rotatable shaft and the internal volume cooperating such that the particulate material is transported by the circumferential groove and not along the remainder of the rotatable shaft; a scraper disposed in relation to the second opening (160), having at its end substantially the same cross section as the groove in the rotating shaft, the scraper cooperating with the groove to dislodge particulate material retained therein, and in response to the shaft rotating, delivers metered amounts of particulate material through the second opening (160); to the flash evaporator (120a).