Archive for the ‘EMO Ether vaporiser’ Category

E.M.O. (ether vaporiser)
Epstein – Macintosh – Oxford.

Below is a link to EMO maintenance in pictures;

EMO maintenance in pictures


Use and maintenance.

This is a sophisticated vaporiser of low internal resistance for use with Ether and air.
It will give percentages from 2 to 20.
It has a water jacket which helps keep the internal temperature stable. It has only two moving parts, the concentration rotor and the temperature compensator; these are set in the factory and should not be touched except in an emergency and then only after reading the service book.

The tests shown below are only to assist you in deciding if the unit is safe to operate.
There are very few repairs you can do with out the service book and spares, however these are such well made units that if they are looked after they should not give trouble for years.

Some simple tests on the E.M.O.

1. Level indicator.
With the ether compartment empty, slowly turn the vaporiser over and check that the indicator moves freely, and falls to the full position and then returns to the empty position when it is turned back.

When filling it up, check that the quantity of ether you put in is as follows.
When the wicks are dry, it will be found that 150 – 200 ml of ether can be poured in before the level indicator lifts from the empty position. A further 300 ml will be required to raise the level indicator to the ‘F’ (full) position. DO NOT OVERFILL.

2. Closing mechanism.
Turn the control to the transit position and connect the outlet of an oxford inflating bellows or other hand ventilating equipment to the inlet of the vaporiser.
Block the outlet of the unit and gently pressurise it.
There should be no escape of air through the filler or through the top of the closing mechanism.

3. Filler.
With the bellows still connected as above and the outlet blocked, open the control knob to 10 and gently apply pressure to the system.
There should be no leakage through the filler.

4. Safety release valve. (this is combined with the closing mechanism)
With the control knob set to 12 and the oxford bellows connected to the outlet of the vaporiser, block the inlet and check that the operation of the bellows draws air in through the safety valve.

5. Temperature compensating unit.
The position of the compensating indicator will show if the unit is in good working order.
It consists of a rod with a black and red band and a metal top.
At 20oC – 25oC the metal top and the black band should show, at temperatures above 32oC the red band will begin to show.
If only the metal band can be seen at 20oC – 25oC the compensating unit is faulty.

6. Water compartment.
If the water used to fill the compartment is suspected to contain high concentrations of salts or chlorine, it is advisable to empty and refill this compartment from time to time.

Some notes on making your own distilled water.
The simple way to make distilled water is to have a water reservoir with sides on it and with a piece of glass angled over the top, leave it in the sun, the water will condense on the glass and run down into an angled water trap and then into a bottle, this is a fairly crude method but will produce better water for your water compartment.
Otherwise you can boil water in a kettle and collect the steam on a glass sheet and let it run in to a bottle.

Some simple repairs.
There are a number of repairs that you can do on these units, however most will need special tools, spare parts and a service book.
For the most part if the machine is looked after you will have very few problems.
The one that you will have, due to the passage of time, is a stiff or seized rotor. This can be cured by following the instructions below.
When it is necessary to gain access to the interior of the E.M.O inhaler, the lid and pointer are removed as an assembly by the following sequence of operations. (see drawing 2.15)

1. Remove handle, 2 screws.

2. Remove ether label on the boss of the pointer, 2 screws.

3. Remove 3 spring dowels, use special tool EMO No5 or a pair of small pointed pliers or mosquito forceps.

4. Set control knob to 6% scale marking, remove plug in handle of control knob. Using a hexagon allen key, EMO tool No 6. Insert it through the hole from which the plug was taken, unscrew and remove 1 allen screw.

5. Remove ‘O’ ring and spring under ether label and keep in a clean position.

6. Remove 5 screws from around the rim of the lid and 3 screws near the centre. The closing mechanism may also be left attached to the lid.

Access can now be obtained to the rotor, if this has become stiff or seized, and to the air inlet port if the closing mechanism has been leaking. Any dirt or foreign bodies should be carefully removed from the mixing chamber.
Removal of control pointer.
If it is necessary to remove the control pointer because of major damage or leaks, the lid must first be removed from the E.M.O.
The pointer is then released by removing the circlip (9), and the various sealing washers shown. When reassembling great care must be taken to replace the washers in the positions shown, and new plastic and rubber parts should always be fitted (if you have them).

Vaporising chamber.
If access is required to the vaporising chamber, the lid pointer assembly must first be removed.
Empty any liquid ether out of the vaporising chamber, remove the water drain plug and empty the water jacket.
Remove all screws around the edge of the mixing chamber, 15 in all, after which the mixing chamber can be lifted off the vaporising chamber. Remove the upper gasket and the three insulating sleeves, and then lift the vaporising chamber out of the water jacket.
The Mk 1 E.M.O. has a cast aluminium water jacket, the Mk 2 has a stainless steel pressed jacket and an aluminium clamp ring which will be free when the screws around the edge have been removed.
In both cases there is a gasket between the vaporising chamber and the water jacket.

To replace the vaporising chamber complete.
Dismantle as above and reassemble by reversing the operation using new gaskets.

Parts required:
Complete vaporising chamber with wicks. 60200.
Gasket lower. 60209
Insulating spacers, set of 3. 60109.
Fibre washers for screws, set of 8. 0100.

When reassembling the following points must be carefully checked:
1. All parts must be properly clean.

2. As the fixing screws around the edge are irregularly spaced, care is necessary to position the gaskets correctly so that all the holes are aligned. It may be necessary to turn the gaskets over to meet this condition. The upper gasket has 3 enlarged holes into each of which an insulated spacer must be fitted. New spacers should be used if the old ones were damaged with dismantling. Careful placing of the upper gasket and the use of spacers ensures that none of the fixing screws make metal contact between the vaporising chamber and the water jacket.
If available, an insulation tester should be used to check electrical insulation after assembly, one probe being held in contact with the water jacket, one with the vapour chamber (most easily reached through the temperature compensating well).

3. The fixing screws should be tightened gradually working alternately on one side and then on the opposite side of the inhaler, in a similar manner to the cylinder head nuts on a car.
They should be finally secured as tightly as possible with a normal screwdriver of the correct size to fit the head.

4. The 8 screws inside the mixing chamber must have fibre washers beneath their heads to ensure sealing. Any damaged washers should be replaced.

Rotor stiff.
If the action of the rotor is stiff it may be removed by twisting and lifting, washed in ether, re-lubricated with a small amount of pure Vaseline (petroleum jelly) and replaced.
Do not disturb either the centre screw or the 3 hexagonal socket screws indicated on the drawing. Ensure that the steel ball is in position at the base of the liner in which the rotor fits.
After re-assembling the complete inhaler check the rotor settings as set out below.

Checking the adjustment of the rotor.
Preparation for adjustment.
The inhaler should have the temperature compensating unit removed as set out below and the top plate of the control knob removed as well, together with the ‘O’ seal and the central spring which will be found below it. The spring dowel marked ‘E’ in fig 1 must not be removed.
A special gauge is required which may be obtained from the manufacturers or made locally to the dimensions shown in fig 2.
Special note: Before carrying out the checks and adjustments set out overleaf, make sure that the rotor is pressed home fully in the inhaler. This is normally performed by the spring which has to be removed, and after every movement of the rotor it must be pressed down to ensure that it has not lifted.

Removal of the temperature compensating unit.
Retained in the inhaler by 3 screws which expand rubber sealing sleeves when tightened.
To remove it from the inhaler slacken all three screws by 3 – 4 turns. Tap the heads of the screws down flush with a piece of wood or plastic. Grip the top of the unit and twist or wriggle slightly to break the grip of the rubber seals.
The unit should now lift out.
It may be necessary to repeat the slackening process if the inhaler has been in use for some time.
DO NOT remove the screws completely as parts may be lost in the inhaler.

Method of checking adjustment of the rotor.

Note: The rotor is correctly adjusted before leaving the factory, and should normally not be interfered with in any way.

These instructions are given for use in cases where dismantling has been necessary for servicing and must be stuck to in detail.
The rotor has both vertical and angular adjustment relative to the vapour port.
Vertical adjustment is effected by adjustment screw A which is locked by nut B.
Angular adjustment is provided by slackening 3 screws C and D. Screw C is a clamp only, those marked D have coned ends and by slackening one slightly and tightening the other, fine adjustments to the pointer can be made. (see fig 1)

To re-fit.
Make sure the three screws are slack, slide the unit into the inhaler body, check that the top plate is fitting correctly to the inhaler without gaps, and tighten the three screws.
To check the vertical adjustment.
Set the pointer at 4%. Insert the gauge into the temperature compensating well holding the long leg vertically. The short leg can then be entered into the vapour port until the mark on the side of the gauge is level with the edge of the temperature compensating well.
At this point the width of the gauge in the rotor is 0.100″ (2.54mm) and the gauge should fit the gap between the rotor and the liner without slackness.

To adjust the rotor vertically, if necessary (fig 3).
Slacken nut ‘B’, screw OUT the adjuster ‘A’ and press down on the rotor. Screw IN the adjuster ‘A’ until the gauge, when applied as above, indicated that the gap is 0.100″.

To check the angular adjustment (fig 4).
Set the pointer at the figure ‘1’ of the 10% mark. Insert the gauge as before but check that the gap between the main step of the rotor and the edge of the port is as in fig 4.
This dimension should be 0.125″. (3.15mm).

To adjust rotor if angular position is incorrect.
Turn pointer until gap is wide enough to insert gauge as shown in fig 4, then turn pointer back until gauge is gripped. Slacken screws ‘C’ and ‘D’ (fig 1) and set pointer to the ‘1’ of the 10% mark, making sure that the rotor does not move. Tighten screw ‘C’ finger tight only and make final adjustment to the ‘1’ by tightening screws ‘D’ a little at a time. Tighten screw ‘C’ fully.
Remove gauge and re-check the gap as set out above.

Rotor seized.
If the rotor has become immovable, a small quantity of penetrating oil should be applied round the edge of the upper surface and through the ether port, reached via the temperature compensator well. Gentle warmth helps the action of the penetrating oil, which may take several hours to release the joint.
Using no undue force, grip the rotor boss with EMO tool No 2 or put the top back on and use the pointer (a temporary pin can be put in place instead of the spring dowels).
Attempt to turn and lift the rotor.
If it is still immovable, unlock and remove the central lock nut and tighten the central screw. This will lift the rotor in the casing and help break the point of seizure. Repeat the process of oiling, twisting and lifting until the rotor is completely removed.
At no time should undue force be used. The inhaler may be damaged permanently unless great care is taken.
In case of difficulty return the unit to the manufacturer.
The cause of the seizure is either a foreign substance in the ether, such as lacquer off the ether cans, or the use of ether which has decomposed and contains aldehydes, In the latter case the liner may show considerable corrosion which must be carefully removed by scraping with a suitable steel tool.
On no account use sandpaper, emery cloth or steel wool which may leave abrasive particles behind.
The rotor should be cleaned with metal polish, lubricated and re-assembled as described later.

If you are unable to get any penetrating oil make your own. Mix ether and a light oil in a 50/50 mixture.

Temperature compensating unit.
If you suspect a fault with this unit as a result of the test earlier, the following procedure may be carried out.
Remove the compensator following the instructions given earlier.
If the room temperature is above 21oC, put the canister part of the unit into iced water for about a minute. Remove it from the water and with finger and thumb around the lower sealing ring, press first up then down on the stepped valve disc ‘X’. This should move against springs in each direction, but if the E.M.O. has been left out of use for sometime in an extreme temperature it may have become stuck on its spindle. Firm pressure will generally release it.
If it cannot be released the whole unit will have to be replaced.

Now immerse the canister in iced water as before and watch that the whole stem and disc ‘X’ move down and the visual indicator also falls.
Now put the canister in fairly hot water, 40oC, and check that the stem, disc and indicator rise.
The disc should completely block the hole in the lower sealing ring and the indicator should rise until the red part is visible through the glass.
Transfer back to the cold water once again and check that the movement is now correct.
Replace the unit back into the E.M.O.

NOTE: On no account touch either the two nuts at the top of the stem or the grub screw at the top of the can. These control basic adjustments which have been correctly set at the factory.

Closing mechanism.
Retained in the inhaler by 2 dogs operated by screws (marked A on the drawing).
To release the unit, unscrew these by 2 or 3 turns only, tap the top of the unit lightly with a piece of wood or the plastic handle of a screwdriver to break the grip of the sealing washer.
A further turn on each screw should then release the dogs and the complete unit can be lifted out.
To reassemble the closing mechanism to the inhaler, make sure that the dogs are turned in fully and insert the unit into its seating, checking that the tongue provided on the inhaler fits into the slot in the closing mechanism body.

Tighten the 2 screws by one turn, lift the unit to check that both dogs are engaged properly and then tighten screws fully.

The part number of a complete replacement unit is: 60900.
spare parts are as follows:
Item 1. Body sealing washer. 60923.
Item 2. Relief valve washer. 60924.
Item 3. Valve assembly. 60930.
Item 4. Split pin. 092.
To fit new valve assembly.
Remove split pin (4) and small washer. Discard split pin (keep it if you have no other). Using a pair of fine pliers disengage the spring wire (6) from the hole in the valve stem.
Remove the complete valve stem assembly and fit new unit by reversing the above procedure. Use a new split pin if you have one.

To fit a new relief washer.
Pull down spring (8) and hold the spindle (7) inside it. By pressing the spindle away from the closing mechanism body the top end can be disengaged and the washer then readily replaced.
To fit a new body sealing washer.
Remove 2 screws (A) and dogs and adjusting screw (B). Remove the old washer by stretching it over the body; fit the new washer in the same manner. Reassemble dogs and screws (A) and (B). Check with the drawing for the correct position.
The dogs should be a tight fit on screws (A). Re-adjust unit as described below.

Adjustment of unit fitted to inhaler.
After fitting a new unit adjustment may be required to ensure correct seating of the valve. Screw (B) is provided for this purpose.
Turning this screw clockwise will increase the closing pressure on the valve.
The screw should be adjusted so that the control pointer can operate the closing mechanism without undue force, and the valve closes soundly when checked as set out earlier.

Level indicator.

This is retained in the unit by 3 screws.
The part number for a replacement unit is 60600

Items 1 & 2. Top assembly with glass. 60601/12.
Items 3 & 7. Indicator pole and assembly. 60608.
Item 4. Gasket. 60616.
Item 5. Screw. 0145.
Item 6. Case assembly. 60604.
Item 8. Glass float with wire. 60613.
New glasses are not supplied separately as this item is sealed into the metal top with a special cement.

This is retained in the unit by screw thread. A special split screwdriver is necessary for removal. Tool number E.M.O.1.
Replacement unit. 60500.
Spare gasket. (item 5). 60517.

To fit a new float glass.
The wire on the glass float is crimped into the tube No7. To release the old wire, squeeze the tube across the direction of the crimping and pull the wire out with a straight pull.

Insert the wire on the new float, and crimp the tube lightly with a pair of pliers.
Fit the level indicator assembly in to the empty E.M.O. and check the position of the indicator when the float is resting on the bottom of the empty ether chamber. Adjust so the indicator is level with the two arrows on either side of ‘E’ by pulling or pushing the float as required.
When the position is satisfactory, crimp the tube in a second place more heavily to secure the float wire.
Here are a few other problems you may come across and what to do about them:
1. Ether escaping, although the control is closed for transit.
a. Broken level glass, replace.
b. Broken indicator glass on the temperature compensating unit, replace compensator.
c. Closing mechanism not shutting, adjust or replace mechanism unit.

2. Concentrations initially appear to be higher than normal but drop off quickly after use.
a. Temperature compensator not operating, carry out checks as above.
b. Filler left open, close.

3. Concentrations appear to be lower than normal.
a. Leak in the circuit, find and cure.
b. Relief valve on closing mechanism stuck open. Carry out checks on safety valve as in 4 above.
Replace as necessary.
c. Overfilled with ether so that the vaporising surface is too small. Pour out the excess ether and check the level indicator.
d. Temperature compensator not working, check as above.

4. Level indicator fails to rise when the ether is added but moves freely when the unit is inverted.
a. Broken float, replace level indicator.

5. Level indicator sticks at any point and will not move when the inhaler is inverted.
a. Float caught by a frayed wick. Remove the unit and cut away the frayed ends of the wick with a pair of scissors.
b. Caught by collapsed ether compartment due to gas build up in the water jacket owing to the use of impure water. Return to the maker or their local agents for repair.

Cleaning and sterilising.
No antiseptic solutions must be used to clean the inhaler. The outside may be cleaned by wiping over with a damp cloth or where it is more seriously contaminated one damped in ether.

Sterilising is not normally necessary as the inhaler is used on open circuit, protected from contamination by non return valves. If special circumstances make it necessary to sterilise, the only suitable method is the use of Ethylene Dioxide gas.
Excessive heat due to boiling or autoclaving would render the inhaler useless.

When storing an E.M.O, O.M.V or Oxford bellows cover them to keep out the dust
(not a plastic bag, they may sweat) and put a bung into the inlet and outlet to prevent insects getting inside and building nests or dying.

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