ATEX Additive Injection Device with External Motor and Flame-Path Seal

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Solution Overview

Problem

Existing fuel distributor additive injection devices are bulky and expensive due to the use of ATEX motors, which are required for safety in explosive environments but are more costly and larger than conventional motors.

Innovation Solution

A compact and cost-effective ATEX additive injection device is designed with a non-ATEX motor housed in an explosion-proof casing, where the suction pump is external and driven by the motor via a drive shaft through the casing wall, utilizing a flange with narrow flame paths to ensure safety without the need for additional electrical cables and a vertical stack configuration to minimize size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ATEX motors are used to ensure safety in explosive atmospheres, then safety compliance is improved, but device size and cost increase

Engineering Contradiction:

Improvesafety complianceVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The device is divided into two separate parts: a non-ATEX motor located outside the hazardous area and an ATEX-compliant pump unit inside the hazardous area. This segmentation allows the motor to be smaller and cheaper while the pump unit maintains safety compliance, resolving the contradiction between safety requirements and device size.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A magnetic coupling mechanism acts as an intermediary between the non-ATEX motor and the ATEX pump unit, transmitting rotational force without requiring a physical shaft penetration that would compromise the explosion-proof seal. This allows the motor to be located outside the hazardous area while still driving the pump inside, reducing overall device size and cost.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If ATEX motors are used to ensure safety in explosive atmospheres, then safety compliance is improved, but device cost increases

Engineering Contradiction:

Improvesafety complianceVSAvoiddevice cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention replaces the expensive ATEX motor with a combination of a cheap non-ATEX motor and a compact ATEX pump unit. The motor, which is the most expensive component, is moved outside the hazardous area where ATEX certification is not required, significantly reducing overall device cost while maintaining safety compliance through the pump unit's certification.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If multiple injection units are included in the additive injection device, then functionality is improved, but device size and cost increase

Engineering Contradiction:

Improveinjection capabilityVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The ATEX pump unit is designed as a universal module that can accommodate multiple injection units (single, twin, or multi-channel) while maintaining the same compact footprint. The pump's rotational mechanism can drive multiple injection needles simultaneously, providing versatile injection capability without increasing device size or requiring additional ATEX motors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution allows for a more compact and affordable ATEX additive injection device that can be used in explosive atmospheres, reducing the bulkiness and expense of existing systems while maintaining safety standards, and can be integrated into existing fuel distributors without modifying their frame.

Implementation Method 1

The motor and the pump are magnetically coupled to one another

Methodology Applied

Scientific EffectMagnetic coupling: Magnetic Field

Implementation Method 2

a first flame path is provided between the flange and the wall

Methodology Applied

Scientific EffectFlame path:

Data Source

PatentEP3365268B1Fuel distributor, the hydraulic compartment of which is equipped with an additive injection device

Publication Date: 2019.10.16 TOKHEIM HOLDING BV

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AI summary

Fuel distributor (1) comprising a hydraulic compartment (2) comprising at least one pumping unit (4) connected to at least one fuel distribution line (3) comprising a fuel flow meter (5) and a flexible tube (6) equipped with a nozzle (7), as well as at least one additive injection device (8) comprising an additive reservoir (9) and at least one injection unit (12) intended to suck a regulated quantity of additive from the additive reservoir (9) to the fuel distribution line (3), said injection unit (12) comprising a suction pump (10) driven by a motor (11), characterised in that the injection unit (12) comprises an explosion-proof housing (13) in which the motor is housed (11), the suction pump (10) being mounted outside of the explosion-proof housing (13) and being driven by the motor (11) via a drive shaft (14) passing through a wall (15) of the explosion-proof housing (13), the suction pump (10) and the motor (11) being separated by said wall (15) of the explosion-proof housing.