Source: https://guthlabs.ai/docs/instruments/orifice-flow-meter-calculator/implementation/

instrument implementation / implementation-contract

# Orifice Flow Meter Calculator implementation

A source-bound implementation contract for Orifice Flow Meter Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-with-binding-errata

**Evidence ID**: t4-273

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification exposes undefined behavior at d=D because 1−β⁴ becomes zero, and at negative ΔP because the square-root argument becomes negative. It also does not specify whether velocity is pipe velocity or orifice velocity, nor how pressure direction should be represented.

## Required corrections

````
[
  {
    "vector": 2,
    "field": "velocity_orifice_m_s",
    "wrong": 2.025912,
    "correct": 2.024911,
    "cause": "minor: inconsistent with her own correct Q/Ao in 4th digit"
  }
]
````

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "D_m": 0.1,
    "d_m": 0.05,
    "delta_P_Pa": 10000,
    "Cd": 0.61,
    "rho_kg_m3": 1000
  },
  "expected_outputs": {
    "Q_m3_s": 0.005532088,
    "velocity_pipe_m_s": 0.704367,
    "velocity_orifice_m_s": 2.817469
  },
  "working": "β=d/D=0.05/0.1=0.5; β⁴=0.5⁴=0.0625. A2=π(0.05²)/4=0.001963495 m². √[2ΔP/(ρ(1−β⁴))]=√[20000/(1000×0.9375)]=√21.333333=4.618802 m/s. Q=0.61×0.001963495×4.618802=0.005532088 m³/s. A1=π(0.1²)/4=0.007853982 m². V1=Q/A1=0.005532088/0.007853982=0.704367 m/s. V2=Q/A2=0.005532088/0.001963495=2.817469 m/s."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/orifice-flow-meter-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/orifice-flow-meter-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/orifice-flow-meter-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`

- `tranche errata record`