Surveying Prism Dehumidification for Tachymeter Accuracy

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Solution Overview

Problem

Condensation and ice formation on survey prisms in tachymeter measurement arrangements impair optical functions, leading to inaccurate measurements and safety concerns on construction sites, as manual removal can alter the prism's position and is time-consuming.

Innovation Solution

A reflector device with a dehumidification facility, including a heating device, is integrated into the survey prism to prevent water settlement by evaporating condensation and melting ice, ensuring continuous accurate measurement without manual intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If manual removal of water deposits is performed, then the surveying prism can be cleared of condensation and ice, but the exact positioning of the surveying prism is altered and subsequent measurements are falsified

Engineering Contradiction:
Improvewater deposits on surveying prismVSAvoidmeasurement accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The heating device is activated before measurements are taken to prevent water deposits from forming on the surveying prism. By applying heat in advance, condensation and ice are eliminated before they can interfere with the optical function, ensuring measurements are taken on a clean, undisturbed prism surface.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The manual mechanical removal method (using cloths or ice scrapers) is replaced with an automated thermal system. The heating device uses electrical or thermal energy to melt and evaporate water deposits automatically, eliminating the need for physical contact that would displace the prism and compromise measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If manual removal of water deposits is performed, then the surveying prism can be cleared, but increased time and effort are required

Engineering Contradiction:
Improvewater deposits on surveying prismVSAvoidtime for removing water deposits
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The surveying prism equipped with the heating device becomes self-sufficient in removing water deposits. The system automatically activates the heating element when moisture is detected or when environmental conditions favor condensation, eliminating the need for external manual intervention and saving time.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The heating device can operate continuously or periodically to maintain the surveying prism free of water deposits throughout the measurement period. This continuous protection ensures the prism remains optically functional without interruption, eliminating downtime associated with manual clearing operations.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If surveying prisms are positioned at exposed locations for flexible use, then they can be reliably targeted from various points, but safety concerns arise when people need to access elevated surveying prisms

Engineering Contradiction:
Improveflexibility of total station useVSAvoidsafety risks at elevated positions
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The heating device enables the surveying prism to self-maintain its optical function without human access. By automatically removing water deposits, the system eliminates the need for personnel to climb onto elevated structures to clean the prism, thereby removing the safety hazard while preserving the benefit of exposed positioning for measurement flexibility.

Inventive Principle:
Principle #25Self-service

4Object-affected harmful factors

If a heating device is integrated into the surveying prism, then water precipitation is prevented, but the device complexity increases

Engineering Contradiction:
Improvecondensation and ice formationVSAvoidstructure of surveying prism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The heating device is integrated into the surveying prism housing, combining the measurement function and the dehumidification function into a single unified unit. This merging approach adds the necessary heating components without requiring a separate standalone system, thereby limiting the increase in overall device complexity while achieving effective protection against water precipitation.

Inventive Principle:
Principle #5Merging (Combining)

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 dehumidification facility effectively prevents water-related optical impairments, maintaining measurement accuracy and safety by eliminating the need for manual removal, thus reducing time and labor costs.

Implementation Method 1

a layer of condensation evaporates or its precipitation is prevented from the outset

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

the heating device can, in particular, comprise one or more heating coils or heating wires, which are heated by the passage of an electric current

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

The emitted heat can be transferred directly to the surveying prism by contact heat conduction

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

or convectively. In particular, a fan or a pressure vessel can be provided to support convective heating of the surveying prism

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 5

A reflector device (10) for a tachymeter measuring arrangement comprises a surveying prism (12) made of a transparent material, in particular glass, with a reflective property

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3865818B1Reflector device for a tachymeter measurement arrangement and measuring method
Publication Date: 2025.05.14 BAUER SPEZIALTIEFBAU GMBH
  • EP3865818B1 patent drawingFigure 1

AI summary

The invention relates to a reflector device for a tachymeter measuring arrangement with a surveying prism. According to the invention, a dehumidification device to prevent water precipitation is arranged on the surveying prism. The invention further comprises a tachymeter measuring arrangement with such a reflector device and a measuring method using this tachymeter measuring arrangement.