Pressure Transmitter Welding Sequence and Corrosion Prevention

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Solution Overview

Problem

The existing methods for producing pressure transmitter systems are complex and expensive, with poor resistance to corrosive environments due to inaccessible weld seams and accumulation of environmental media, leading to corrosion and oil leaks.

Innovation Solution

A method that changes the welding sequence to form the pressure transmitter system from the inside, using a protective gas atmosphere to prevent scaling and corrosion, and redesigns the structure to prevent environmental medium accumulation, with the capillary tube welded to the capillary adapter using orbital, TIG, or laser welding, and the protective hose fixed via welding or pressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the capillary tube is welded to the capillary adapter before fixing the adapter to the diaphragm seal body, then the welding can be performed with manual tracking, but the production process becomes complex and expensive

Engineering Contradiction:

Improvewelding process simplicityVSAvoidproduction process complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The capillary adapter is fixed to the diaphragm seal body in advance before the capillary tube is welded. This preliminary positioning action allows the subsequent welding to be performed more easily with proper alignment, rather than attempting to track and weld the tube during the fixing process itself.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The production process is divided into distinct sequential steps: first fixing the adapter to the diaphragm seal body, then welding the capillary tube to the already-positioned adapter. This segmentation of operations simplifies each individual step compared to attempting to perform both operations simultaneously.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the weld seam between the capillary adapter and capillary tube is not accessible for post-processing, then the production process is simpler, but corrosion formation occurs more frequently

Engineering Contradiction:

Improveproduction process simplicityVSAvoidcorrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Instead of welding the capillary tube to the adapter first and then fixing the adapter (which would make the weld seam inaccessible), the sequence is inverted: the adapter is fixed to the diaphragm seal body first, then the capillary tube is welded to the exposed adapter. This inversion makes the weld seam accessible for post-processing treatment to prevent corrosion.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If the hole in the capillary adapter is designed to receive the protective hose, then the protective hose can be secured, but the hole creates a collecting function for liquids leading to increased corrosion

Engineering Contradiction:

Improveprotective hose fixationVSAvoidcorrosion from liquid accumulation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The harmful function of the hole (liquid collection) is separated from the useful function (protective hose reception). The protective hose is fixed to the adapter using alternative means such as clamps or clips that do not require creating a hole that would collect liquids, thereby extracting the harmful liquid accumulation function while preserving the hose fixation function.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This approach simplifies and cost-reduces the production of pressure transmitter systems, enhances corrosion resistance, and increases their lifespan by preventing environmental medium accumulation and allowing for accessible weld seam post-processing.

Implementation Method 1

Since the welding is carried out in a protective gas atmosphere as standard, temper colors and scaling on the inside of the capillary tube can be prevented.

Methodology Applied

Scientific EffectProtective gas atmosphere:

Implementation Method 2

the capillary tube is welded to the capillary adapter by means of an orbital, TIG or laser welding process

Methodology Applied

Scientific EffectOrbital welding:

Implementation Method 3

the capillary tube is welded to the capillary adapter by means of an orbital, TIG or laser welding process

Methodology Applied

Scientific EffectTIG welding:

Implementation Method 4

the capillary tube is welded to the capillary adapter by means of an orbital, TIG or laser welding process

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3458821B1Method for producing a pressure transmitter system

Publication Date: 2023.08.16 ENDRESS & HAUSER GMBH & CO KG

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AI summary

Disclosed is a method for producing a pressure transmitter system (1), comprising the following steps: - providing a capillary adapter (3) and a pressure transmitter (2), the pressure transmitter having at least one membrane support body (6) and a separation membrane (8) that is gas-tightly connected along at least one edge to the membrane support body (6) to form a pressure chamber (9) between the separation membrane (8) and the membrane support body (6); - welding the capillary adapter (3) to the pressure transmitter (2); - positioning together the capillary tube (4) and a capillary interface (15) of the capillary adapter (3); - bonding the capillary tube to the capillary adapter (3) by welding; - placing a protective hose (5) onto a protective hose mounting (16) of the capillary adaper (3).