VAPORISER- functioning lecture selva.ppt

vaporisers

1. VAPORISERSVAPORISERS
Dr.R.SelvakumarDr.R.Selvakumar
Asst.Professor,G.R.HAsst.Professor,G.R.H

2. The most simple vaporiser could be…The most simple vaporiser could be…
A handkerchiefA handkerchief

3. A little improvised vaporiser….A little improvised vaporiser….
A Tea filter

4. SO..SO..
Vaporisers were thought to be enough if they..
•Provide vapor to inhale
•Are simple enough to be carried by the anesthetist

5. ONCE CURARE WAS INTRODUCED..ONCE CURARE WAS INTRODUCED..
•Need for the vaporiser to work in a controlled
ventilation set up
•Required precision in the dosage
•Needed to avoid inadvertent over dosage
•Potent and costly inhalational agents

6. THE DRAWBACKS OF A SIMPLE VAPORISERTHE DRAWBACKS OF A SIMPLE VAPORISER
Cant provide exact concentration of vapor
Output concentration cant be constant
WHY..?WHY..?

7. TO REASON OUT…TO REASON OUT…
Going in to the basics…
GAS Vs VAPORGAS Vs VAPOR

8. VAPORISER:VAPORISER: instrument designed to convert a liquid
into its vapor and deliver a controlled amount of the
vapour to the flow of gases going to the patient

9. SATURATED VAPOUR PRESSURE:SATURATED VAPOUR PRESSURE:
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T-35
P-240
T-60
P-570

10. WILL ETHER BOIL DURING SUMMERWILL ETHER BOIL DURING SUMMER
IN MADURAI IN THE OPERATING ROOM?IN MADURAI IN THE OPERATING ROOM?

11. BOILING POINTBOILING POINT
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A liquid will boil if its SVP touches the atm.pressure

12. 2% Halothane2% Halothane
What does 2% mean?What does 2% mean?
Volume % = Partial pressure / Atm. Presure x 100

13. Does heat necessary for vaporisation?Does heat necessary for vaporisation?

14. Heat of vaporisationHeat of vaporisation
…of a liquid is the number of calories necessary
to convert 1 gm of liquid into vapour
Where it is supplied from?Where it is supplied from?

15. SPECIFIC HEAT CAPACITYSPECIFIC HEAT CAPACITY
Quantity of heat required to raise the temperature
of 1 gm of the substance to 1cc.

16. If heat has to come from the sorrounding , vaporiser
Must be made up of good conductor of heat…
THERMAL CONDUCTIVITYTHERMAL CONDUCTIVITY

17. THERMAL CONDUCTIVITYTHERMAL CONDUCTIVITY
Is a measure of speed with which heat flows
through a substance.It is the amount of heat
that flows through a unit area of plate of unit
thickness per degree of temperature gradient
per unit time

18. MATERIAL USED IN CONSTRUCTION OF VAPORISERMATERIAL USED IN CONSTRUCTION OF VAPORISER
Material Sp.heatTher.con
Copper
Aluminium
Glass
Steel
brass
0.1
0.214
0.16
0.107
0.0917
0.92
0.504
0.0025
0.115
0.260

19. TYPES OF VAPORISERSTYPES OF VAPORISERS
Variable by-pass vaporisers:
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20. Measured flow vaporisers:Measured flow vaporisers:
•Two flow meters
•Bubble through vaporisation
•e.g: copper kettle, desflurane

21. FLOW OVER VAPORISERFLOW OVER VAPORISER
•The carrier gas passes over the surface of the liquid
and takes away the vapour.
•Factors affecting the vaporisation:
1.vapour press. of the liquid
2. Efficiency of vaporisation
the arera of gas-liquid interface
the velocity of carrier gas flow
height of gas flow above the liquid

22. FLOW OVER VAPORISER-contd..FLOW OVER VAPORISER-contd..
•Area of Gas-Liquid interface
baffles or spiral tracks
wicks
•Velocity of carrier gas
low or high flow
•Height of gas flow above the liquid
plunger system in ether bottle

23. BUBBLE-THROUGH VAPORISERS:BUBBLE-THROUGH VAPORISERS:
•Size of the bubbles
•Depth of the liquid
•Velocity of carrier gas flow

24. Location of the vaporiser:Location of the vaporiser:
•Out of system vaporiser
•In system vaporiser
-resistance
-Determinants of vaporiser output
capability of vaporiser
vaporiser concentration and output

25. TEMPERATURE COMPENSATED VAPORISERSTEMPERATURE COMPENSATED VAPORISERS
•By supplied heat
copper, water jacket, electric heater
calcium crystals
•Gas flow compensation

26. Functioning of vaporisers:Functioning of vaporisers:
Effect of back pressure
PUMPING EFFECT:PUMPING EFFECT:
•Magnitude of back pressure
•Flow of carrier gas
•Dial setting of the vaporiser

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PUMPING EFFECTPUMPING EFFECT

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PRESSURISING EFFECTPRESSURISING EFFECT
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29. PRESSURISING EFFECT:PRESSURISING EFFECT:
•Seen in high flows
•Vaporiser concentration decreases
•Interplay of both effects

30. EFFECT OF CARRIER GAS ON VAPORISER
OUTPUT
•Solubility of N2O in liquid agents-4.5 ml of N2O per ml
of liquid anesthetic.
•Vaporiser output increases if N2 is used instead of N2O

31. EFFECT OF BAROMETRIC PRESSUREEFFECT OF BAROMETRIC PRESSURE
•Volume % increases
•No alteration in terms of partial pressure
C’ = C x p/p’C’ = C x p/p’

32. ARRANGEMENT OF VAPORISERS:ARRANGEMENT OF VAPORISERS:
Depending on
•Volatility
•Potency
•Toxicity
•Reason for using selectatec

33. ……………………
BOYLE’S BOTTLE-ETHER VAPORISERBOYLE’S BOTTLE-ETHER VAPORISER
hood
U tube
plunger

34. BOYLE’S BOTTLE-ETHER VAPORISERBOYLE’S BOTTLE-ETHER VAPORISER
•Variable bypass
•Flow over or bubble through
•Out of system
•No temperature compensation

35. BOYLE’S BOTTLEBOYLE’S BOTTLE
Vaporiser output depends
on:
•Temperature of the liquid
•Plunger level
•Position of the control lever
•Volume flow of the carrier gas
•Level of the liquid in the vaporiser
•Agitation of the vaporiser

36. FLUTEC-MARK IIIFLUTEC-MARK III
•Variable bypass
•Flow over with wick
•Out of system
•Temperature compensation by flow alteration
•Bi-metallic strip
•Agent specific
•Volume of vap.chamber-270 ml, wicks-35 ml

37. GOLDMAN VAPORISERGOLDMAN VAPORISER
Variable bypass,flow over,in or out of system
VOC
8 lpm
VIC
3 lpm
1 0.1 0.5
2 0.5 2.0
3 1.5 3.5
On 2.5 3.8
Dial position

38. TEC-6 VAPORISERTEC-6 VAPORISER
•Agent specific- desflurane
•Measured flow
•Pressurized vapour added to the carrier gas
•Liquid desflurane is heated to 39
0
C
•Vapour under 1500 mm of Hg pressure
•Pressure regulating valve and
•concentration control dial decide the vaporiser output