Reduc vals, reguls  flowmtrs bb 10.11
Upcoming SlideShare
Loading in...5
×
 

Reduc vals, reguls flowmtrs bb 10.11

on

  • 883 views

purpsoe, function and application

purpsoe, function and application

Statistics

Views

Total Views
883
Views on SlideShare
883
Embed Views
0

Actions

Likes
0
Downloads
35
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment
  • Different connections, density of gases

Reduc vals, reguls  flowmtrs bb 10.11 Reduc vals, reguls flowmtrs bb 10.11 Presentation Transcript

  • REDUCING VALVES, REGULATORS & FLOWMETERS
  • DEFINITIONS
    • Reducing valve – a valve that reduces a higher pressure to a lower pressure
    • Flowmeter- a device that controls & indicates flow
    • Regulator – a reducing valve & a flowmeter
  • Reducing Valves? What’s important?
    • These types of valves decrease high pressures - 2200 psi to working pressure - 50 psi for most respiratory therapy equipment
    • Also used to decrease the bulk storage pressure to 50 psi
    View slide
  • Reducing valves (regulators) Classification
    • Single-stage regulator- two opposing forces (spring tension and gas pressure) are separated by a thin diaphragm
      • The diaphragm is straight & the inlet valve is closed when the forces are equal
      • The spring tension (for resp. set @ 50 psi but may be adjustable) should be equal to the gas pressure, but when the gas pressure drops, the inlet opens and gas enters and equilibrates to the spring tension
    View slide
  • Multi-stage Regulators
    • Utilizes two or more single stage regulators in a series
      • Double stage – 2200 psi to 700 psi to 50 psi
      • Triple – 2200 psi to 700 psi to 300 psi to 50 psi
      • Multistage are more precise and have more “laminar” flow
      • EACH STAGE MUST HAVE A POP-OFF VALVE TO RELEASE EXCESS PRESSURE
      • COUNT THE POP-OFFS TO IDENTIFY THE # OF STAGES
  • Preset Reducing Valve
    • A Gas inlet
    • B Gauge
    • C High pressure chamber
    • D Low pressure chamber
    • E Diaphragm
    • F Spring
    • G Valve stem
    • H Inlet valve
    • I Gas outlet
    • L Safety vent
  • Adjustable Reducing Valve
  • Bourdon Gauge
  • It’s a Bourdon Gauge!! But how does it work?
    • Basically, pressure enters a chamber that has a fixed orifice outlet. As the pressure is increased, the coiled copper tube straightens out and the needle valve turns to read a higher unit.
    • Bourdon gauges can be calibrated to read pressure – Bourdon regulator
    • Or a Bourdon gauge can be calibrated to flow - a Bourdon flowmeter
  • Bourdon Gauge
  • Bourdon spring
  • Thorpe tubes
  • Thorpe-Tube Flowmeters 2 Types
    • 1. Non-back pressure compensated thorpe-tube flowmeter
      • The needle valve is before the tube indicator
      • The thorpe-tube is not pressurized to 50 psi
      • Back pressure will cause the float to drop and the patient will receive more flow than the tube indicates
  • Thorpe-tube flowmeters Compensated
    • 2. Pressure-compensated Thorpe-tube flowmeter
      • Needle-valve (flow control) located distal to the Thorpe-tube
      • Pressure in tube is pressurized to 50 psi
      • If resistance is placed downstream from the Thorpe-tube the flow will read accurate
    • Uncompensated
    • Compensated
  • How to tell the difference?
    • 1. The label
    • 2. “Test” With the needle valve turned off, place the flowmeter in a 50 psi gas source, if pressure-compensated, the float will jump up and fall back to zero
    • Location of the needle valve ?
    • Occlude outlet and read flow?
  • FLOW RANGE FOR FLOWMETERS
    • Usually a flowmeter is incremented up to 15 L /min
    • This varies-
      • Neonate – mL/min
      • Incremented up to 3 L/min
      • Pediatrics up to 8 L/min
      • Some adult flowmeters go up to 25 L/min
  • BOURDON FLOWMETER
    • A reducing valve that controls the pressure gradient thru a fixed orifice
    • As the driving pressure increases the flow exiting the orifice increases
    • NOT-pressure compensated
    • If back pressure is placed downstream, the meter will read higher than what is exiting the orifice
  • regulators
    • 1. Thorpe-tube type- has to stay vertical
    • 2. Bourdon type- good for transports
  • FLOW RESTRICTORS – functions like a Bourdon
    • Type 1 –Fixed-orifice
    • Type II – Adjustable-orifice