Flow Plug Length-to-Hole Uniformity for Pressure Loss Reduction

Solution Overview

Problem

Multi-hole orifice plates in flow meters often result in varying permanent pressure losses and less than optimal confidence in flow measurement due to non-uniform hole placement and size, leading to suboptimal flow conditioning and measurement accuracy.

Innovation Solution

A flow plug with a plurality of holes of varying thickness, where each hole has a consistent length-to-size ratio, is used to condition fluid flow, minimizing pressure loss and optimizing the coefficient of discharge and vena contracta for improved measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multi-hole orifice plates are used for flow conditioning and measurement, then flow measurement can be performed without moving parts or power requirements, but permanent pressure losses vary widely and measurement confidence is reduced due to non-uniform hole placement and size

Engineering Contradiction:

Improveflow measurement confidenceVSAvoidpermanent pressure loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent applies local quality by ensuring that each hole in the orifice plate has a uniform length-to-diameter ratio, while allowing different holes to have different diameters. This local uniformity in the critical dimension (length-to-diameter ratio) ensures consistent flow characteristics and uniform vena contracta formation across all holes, resolving the measurement confidence issue while maintaining the multi-hole configuration for adequate flow capacity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the critical parameter from variable hole dimensions to uniform length-to-diameter ratio across all holes. By controlling this specific parameter uniformly while allowing other dimensions to vary based on flow requirements, the invention achieves both adequate flow capacity (through multiple holes of appropriate sizes) and consistent measurement performance (through uniform geometry that produces uniform vena contracta)

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If multi-hole orifice plates with varying hole placement and size are used, then adequate flow capacity can be maintained, but coefficient of discharge is not optimized and vena contracta are non-uniform

Engineering Contradiction:

Improveflow capacityVSAvoidhole uniformity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by ensuring that each hole in the orifice plate has a uniform length-to-diameter ratio, while allowing different holes to have different diameters. This local uniformity in the critical dimension (length-to-diameter ratio) ensures consistent flow characteristics and uniform vena contracta formation across all holes, resolving the measurement confidence issue while maintaining the multi-hole configuration for adequate flow capacity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the critical parameter from variable hole dimensions to uniform length-to-diameter ratio across all holes. By controlling this specific parameter uniformly while allowing other dimensions to vary based on flow requirements, the invention achieves both adequate flow capacity (through multiple holes of appropriate sizes) and consistent measurement performance (through uniform geometry that produces uniform vena contracta)

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8132961B1Flow plug with length-to-hole size uniformity for use in flow conditioning and flow metering

Publication Date: 2012.03.13 UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR NAT AERONAUTICS & SPACE ADMINISTRATION

AI summary

A flow plug of varying thickness has a plurality of holes formed therethrough. The plug fits in a conduit such that a fluid flow in the conduit passes through the plug's holes. Each hole is defined by a parameter indicative of size in terms of the cross-sectional area thereof. A ratio of hole length-to-parameter is approximately the same for all of the holes.