Cylinder And Pipeline System.pptx final.pptx

Cylinder And Pipeline System.pptx final.pptx

1. MEDICAL GAS CYLINDERS PRESENTER – DR. SHILPA M MODERATOR - DR. MERIN

2. TOPICS FOR DISCUSSION DEFINITIONS CONTENT AND PRESSURE SIZES PARTS TESTING AND FILLING MARKINGS AND LABELING PIN INDEX COLOUR CODING SAFE USAGE RULES HAZARDS SAFETY FEATURES

3. Definitions Psi : Pounds per square inch Psig : Pounds per square inch gauge(difference between measured pressure and surrounding atmospheric pressure) Psia : pounds per square inch absolute Psia = psig + local atmospheric pressure Eg : At sea level – atmospheric pressure is 0 but psia is 14.7 psia Units of Pressure : 1 Atmosphere = 14.7psi / 760 mmHg 1030cm of H 2 o 1000mbar 100Kpa

4. Definitions Critical Temperature: -Defined as the temperature below which no gas can be liquefied irrespective of which pressure is applied Critical Pressure: -Defined as the minimum pressure required to liquefy a gas at its critical temperature

5. Compressed Gas It is defined as any mixture having in a container an absolute pressure exceeding 40 psi at 70 F OR Regardless of the pressure at 70 F having a absolute pressure exceeding 104 psi at 130 F OR Any liquid having a vapor pressure exceeding 40 psia at 100 F

6. Non-Liquified Gas These are gases that do not liquefy at ambient temperatures regardless of the required pressures applied These gases do become liquids at lower temperatures- called as CRYOGENIC LIQUIDS Example : Oxygen, Nitrogen, Air, Helium Liquified Compressed Gases These are gases which become liquid at ambient temperatures at pressures varying from 25-100psig (172-10340Kpa) Example : N 2 o ,CO 2

7. Sizes Cylinders are manufactured in different Sizes (A - J) A being the smallest and J is the biggest size, A and H are not used for medical gases Volume and Pressure of gas in a particular size cylinder vary O 2 & Air are similar, CO 2 and N 2 o are similar Size E is the most commonly used in anesthesia machine and for patient transport and resuscitation Size D are used limited supplies where size and weight considerations are important

8. Sizes

9. Sizes

10. Contents and Pressure In a cylinder containing a Non - liquefied gas pressure declines as contents are withdrawn ,Hence pressure can be used to measure cylinder volume

11. Contents and Pressure In a cylinder containing liquified gas, the pressure depends on Vapor Pressure of the liquid and is not an indication of the amount of gas remaining in the cylinder as long as contents are partly in the liquid state Pressure remains nearly constant till all the liquid has evaporated After which pressure declines till cylinder is exhausted

12. Contents and Pressure

13. Parts of Cylinder Components Consists of: Body Valve Port Stem Pressure relief devices

14. Body Most of the medical gas cylinders are made of steel with various alloys In recent years , manufacturers have moved from traditional steel cylinders towards steel-carbon fiber cylinders Gas holding capacity is more and light weight MRI compatible cylinders are made of aluminum Modern cylinders are made of Alloy of Molybdenum + Steel +/- Chromium It is used to increase strength and to minimize weight and wall thickness

15. Body Walls of the cylinders vary from 5/64 to ¼ inch thick Cylinders that have a marking 3AA are made of steel or 3ALM 3AL indicates that the cylinder is made from aluminum Cylinder have a flat or a concave base . The other end tapers into the neck that is fitted with tapered screw threads that attach to the cylinder valve

16. Valve Cylinders are filled and discharged through a valve(spindle shaped) attached to the neck It is made of bronze or brass which is heavily plated with nickel/Chromium so as to allow rapid dissipation of heat of compression

17. Valve The end which enters the neck of the cylinders is threaded to fit a corresponding screw thread inside the neck itself A sleeve or washer of soft alloy (containing high lead content) completes the gas tight seal the valve is screwed into the neck of the cylinder Woods metal – I s a fusible alloy of 50% bismuth, 26.7% lead, 13.3% tin, and 10% cadmium by mass. It has a melting point of approximately 70 °C (158 °F). Wood's metal seal which melts in fire, allowing the gas to escape and reducing the risk of gas explosion. Wood's metal is  commonly used as a filler when bending thin-walled metal tubes . For this use the tubing is filled with molten Wood's metal.

18. Valve Cylinder Valves are of various types -Those used on anaesthesia machines are ‘Flush’ types which fit the pin index system For medium and large capacity cylinders - Bull nose valves are used Types of Valves: a) Packed type b) Diaphragm type

19. Packed Type Capable of withstanding high pressure Stem is sealed by resilient packing such as Teflon which prevents leaks around threads Opened by 2-3 turns Used in most of the cylinders

20. Diaphragm Type Stem is separated from the seat Closure between the cylinder interior and atmosphere is accomplished by using a seal & a Bonnet nut that clamps one or more circular discs These discs separate upper & lower stems which may be permanently attached to the diaphragms

21. Diaphragm Type Upper stem is actuated by manual/automatic means & Lower stem shuts/permits flow through valve Can be opened by ½ to ¾ turns Seat does not turn-so less likely to leak Generally preferred when pressures are relatively low and no leaks can be allowed Expensive

22. Port It is the point of exit for the gas It fits into the nipple on the hanger yoke of the anaesthesia machine It should be protected in transit by covering When installing a cylinder on the anaesthesia machine it is important for the user to not mistake the part for the conical depression

23. Conical Depression

24. Conical Depression Conical Depression is situated on the opposite side of the port on the cylinder valve and is situated above the safety relief device It is present on the those cylinders which are designed to fit on anesthesia machine Conical depression is designed to receive the retaining screw on the yoke of anesthesia machine If the retaining screw is fixed into the port it will cause damage to it

25. Stem Each valve contains a stem(spindle/screw-pin) or shaft that is rotated to open or close the cylinder valve It is made up of steel To close the valve the stem seals against the seat that is part of the valve When the valve is opened-stem is moved upwards and allows the gas to flow to the port

26. Pressure Relief Devices Every cylinder is fitted with pressure relief devices whose purpose is to vent the cylinder’s contents to the atmosphere If the pressure of enclosed gas increases to dangerous levels Types of pressure relief devices Rupture Disc Fusible Plug Combination of both Pressure Relief valve(spring loaded)

27. Rupture Disc When Pre-determined pressure is reached the disc ruptures & allows the gas contents to be discharged It is a non-reclosing device held against an orifice It protects against excess pressure as a result of high temperature/overfilling

28. Rupture Disc

29. Fusible Plug It is thermally operated which is made up of woods metal blue , of bronze , brass or gunmetal black It is a non-reclosing pressure relief device where the plug is held against the discharge channel It provides protection against excess pressure due to high temperature but not overfilling Yield Temperature : Temperature at which the fusible material becomes sufficiently soft to extrude from its holder so that the cylinder contents are discharged. Yield temperature – 90 to 105 degree Celsius or 70 to 75 degree Celsius

30. Spring Loaded Pressure Relief Device It is a reclosing device When set pressure is exceeded , the pressure in the cylinder forces the spring to open the channel for letting out the gases Gas flows around the safety valve seat to discharge channel till excess pressure is relieved

31. Handle/Hand wheel

32. Handle/Hand wheel It is used to open or close a cylinder valve It is turned counter-clockwis e to open and clockwise to close causes the stem to turn A good practice is to attach a handle to each anesthesia machine/ other apparatus for which it is needed Ea ch large cylinder has a permanent attached handle that uses a spring & nut to hold it firmly in place

33. Non - Interchangeable Safety Systems With widespread use of cylinders containing different gases, a potential hazard that is encountered is connection of a cylinder to equipment intended for a different gas For safety purposes Color coding for each gas Pin Index Safety System

34. Color Coding Of Cylinders

35. Pin Index Safety System The use of PISS began in 1952 which is introduced by us fire association together with CGA along with the Ameican society of Anesthioslogist In order to ensure that the correct cylinder is attached to the appropriate hanger yoke of the anesthesia machine/workstation A series of pins on the hanger yoke is made to fit into the corresponding indentations(pins/holes) drilled into cylinder valve

36. Pin Index Safety System

37. Pin Index Safety System It consists of holes on the cylinder valve positioned in an arc below the outlet port Position of the cylinder valve are the circumference of a circle of 9/16 inch(14.3mm) radius centered on the port The port has a diameter of 7mm The distance between the centre and lower part of the yoke is 20.6mm

38. Pin Index Safety System Unless the pins and holes are aligned, the/yoke port will not seat The indentations on the cylinder valve block are counted 1-6 from left to right The distance between the centre of the 1 st & 6 th pin should be 16mm There are 7 positions for pins and holes

39. Pin Index Safety System The pins are 4.75 mm in diameter and 6mm long except for pin number 7 which is slightly thicker and placed at the center (between port 3 & 4). 6 holes placed at an angle of 12 degrees from port

40. Bodok Seal A small disk of neoprene with metal periphery ensures a gas tight fit between the cylinder and the anesthetic machine yoke in the form of seal Oil should not be used as a seal because the pressurized gases give of heat as they are released from the cylinder and may cause explosions

41. Cylinder Pressure Gauge Displays the cylinder pressure for each gas The indicator is located near the cylinders / on a panel in front of the machine The scale is 33% greater than the maximum filing pressure of the cylinder(full indication position) Many of the indicators are of the Bourdon tube (Bourdon spring elastic element)

42. OXYGEN : Rate of flow multiplied by 60 gives total consumption in one hour. How to calculate the quantity inside the cylinder ? N 2 O AVAGADRO'S LAW : One-gram molecular weight of any substance will give rise to 22.4 L of gas and will contain 6.024 x 1023 number of molecules MOL.WEIGHT OF O2 = 2 X 16 = 32 N 2 O = 2 X 14+ 16 = 44

43. How to calculate the quantity inside the cylinder ? Amount of N2O Gas in a cylinder Tare weight of the cylinder = 12.5 Kg Cylinder weight with N 2 O = 15 Kg Weight of the N 2 O = 2.5 Kg = 2500G 44 G OF N 2 O = 22.4 L Therefore 2500G = 22.4/44 x 2500 – 1272 L

44. How to calculate the quantity inside the cylinder ? Estimating duration of liquid oxygen cylinder gas flow Weight of gas must be known to determine volume of gas in liquid-filled cylinder 1L of liquid O2 weighs 2.5 lb & produces 860 L of O2 in its gaseous state Amount of gas = Liquid O2 weight (lb) x 860/2.5 lb/L Duration of gas (min) = Amount of gas in container (L)/ Flow (L/min)

45. Duration of gas flow An E cylinders contain 22 cubic feet (cu ft) of oxygen when full ( 2200 psi pressure). One cubic foot of oxygen equals 28.3 L. Now, Tank Factor: (22 × 28.3) L/2200 psi = 0.28 L/psi. Therefore, the time duration for which the tank would last (in minutes). = (Tank factor [gauge pressure – 500])/L flow. = (0.28L/psi [2000 psi – 500 psi])/8 L/min. = 52.5 min.

46. A hollow metal tube which is curved One end is sealed and linked to a clocklike mechanism The other end which is open is connected to the gas source MOA : As pressure increases the curved tube becomes straight Cylinder Pressure Gauge They are calibrated in kg/cm 2 , pounds/inch 2 kilo Pascals(kPa)

47. Testing A cylinder must be inspected and tested at least every 5 years or with special permit up to every 10 years The test date must be permanently stamped on the cylinder Each cylinder must be an internal & external visual check for corrosion and evidence of physical impact or distortion Cylinders are checked for leaks and retention of structural strength by testing to minimum of 1.66 times there service pressure

48. Testing Service Pressure: It is the maximum pressure to which the cylinder may be filled at 70 F Other Tests Done Hydraulic Test Tensile Test Flattening Test Bend Test Impact Test These are carried on at least one out of every 100 cylinders

49. Testing Hydraulic test - Is a measure of cylinder’s elasticity. The cylinder is connected by a thread to testing unit, filled with water and the water level is measured by gauge. The gauge is isolated, and cylinder pressurized to 240 atmospheres. The pressure is released, and gauge opened. The cylinder should stretch less than 0.02%.

50. Testing Tensile test - Done in one out of 100 cylinders . The yield point should not be less than 15 tons per square inch. Flattening test - The cylinder is kept between two compression blocks and pressure is applied from both sides until the distance between blocks remains 6 times the thickness of the wall of cylinder. The walls should not crack.

51. Testing Impact test - Three of each, longitudinal and transverse stripes are taken from a finished cylinder and struck by mechanical hammer. Mean energy to produce the crack should not be less than 5 and 10 lb/ft for transverse and longitudinal strips, respectively. Bend test - A ring of 25 mm width is cut from the cylinder and divided into strips. Each strip is bent inward until inner edges are a part, not greater than the diameter of strip.

52. Filling If a cylinder containing a gas under a safe pressure at normal temperature is subjected to higher temperature the pressure may increase to dangerous levels To prevent this , regulations have been drawn limiting the amount of gas a cylinder may contain Non-Liquefied Gases : are allowed an additional 10 % filling Liquefied gas containing cylinders : Pressure will remain constant as long as there is liquid in the cylinder

53. Filling To prevent cylinder being overfilled the maximum amount of gas allowed is defined by the filling density (filling ratio for each gas) Filling Density : Percent of ratio of weight of the gas in a cylinder to the weight of water that the cylinder would hold at 60 F N 2 o -68%. O 2- 68% • Filling Limits :- Gas in closed container Rise in temp will cause rise in press Pressures can rise to dangerous levels Cylinder may explode. To prevent this, the dept of transportation has regulations

54. Filling • Filling Limits :- Gas in closed container Rise in temp will cause rise in press Pressures can rise to dangerous levels Cylinder may explode. To prevent this, the dept of transportation has regulations

55. Entonox This is 50:50 mixtures of nitrous oxide and oxygen. The premixed contents remain in gaseous phase at pressures and temperature at which N2 O by itself would normally be a liquid. Entonox is compressed in cylinders at a pressure of 13,700 kPa. Cylinders are colored blue with white quadrants on the shoulder. For filling, the cylinders are first filled with the correct weight of nitrous oxide. The cylinder is then inverted and oxygen is bubbled through. As oxygen dissolves in nitrous oxide, the latter vaporizes until all the liquid is vaporized. The mixture remains in gaseous state unless the temperature falls to −7°.

56. Entonox The pseudocritical temperature of Entonox is approximately -7°C. Below this temperature nitrous oxide converts to the liquid phase, with an increasing concentration of oxygen in the gaseous phase. As the oxygen is consumed, the oxygen concentration will eventually drop and a hypoxic gas mixture may develop. Poynting Effect When two gases, one of high and another of low critical temperature are mixed in a container, Ci the critical temperature of the gas with a high critical temperature will decrease to a lower level (pseudo critical temperature) and the mixture will remain as a gas above this pseudo critical temperature.

57. Entonox

58. Heliox Heliox is a mixture of oxygen and helium. The latter is 86% less dense (0.179 g/L) than air (1.293 g/L). A mixture of 21% oxygen and 79% of helium named as Heliox 21 is used to improve gaseous exchange in acute exacerbation of asthma and COPD.

59. Marking/ Labelling /Tags Important for identification To check the test date In case of flammable gases-Caution/Danger/Warning label is needed Tags should contain either full/in use/empty

60. Cleaning of cylinders The cleaning & disinfection procedure should be performed at the hospital in a designated area. For initial cleaning, hot portable water with detergents, not exceeding 50 degree Celsius (50 C) should be used for cleaning cylinders, wheeled cylinder trolley, spanner, keys, regulators and wrench. Valves & inlets should be closed & covered so that the water doesn’t get inside the cylinders/containers. Under no circumstances medical gas cylinder/container should be immersed in water. After cleaning the cylinder/accessories with water and soap, the cylinder/container should be cleaned with 1% sodium hypochlorite solution. Fogging is a suitable alternative.

61. Cleaning of cylinders While cleaning the cylinder/container, avoid cleaning agents that contain ammonia, amine based compounds or chlorine based compounds as they can cause corrosion of steel or aluminum alloy components or stress cracking of brass, including copper alloy components. Personal involved in filling, storing, handling & transporting of Medical Gas Cylinder/Container should be trained in this procedure and should be wearing protective gear at all times as per MoHFW guidelines.

62. Transportation of cylinders 1) Upright position. 2) Wear protective footwear, gloves & goggles. 3) Do not lift by protective cap or guard. 4) Do not subject to temp extremes. 5) Do not drag or role cylinders. Always use cart. 6) Secure with chain all times when kept upright. Otherwise keep them flat on the ground. 7) Ensure cylinders are properly labelled to its contents.

63. Storage of cylinders Storage area should be cool , dry, ventilated , clean area constructed of fire-resistant material should have good access for deliveries and reasonable level floor surface should have segregation pf full and empty cylinders cylinder with an oldest date should be used first cylinders should not be stored in direct sunlight easily visible signs such as no smoking , no open flames or sparks , no oil grease etc. should be displayed cylinders should not be exposed to dampness , corrosive chemicals fumes as they may damage cylinders and cause valve protection caps stick the temperature should not go below 10 degree Celsius where Entonox cylinders are stored cylinders should always be krpt in place with chain or any other restraining device the suitable trolley/ cart should be used to transport and support the cylinder

64. Hazards Incorrect Cylinder Incorrect Valve Incorrect color/Labelling Damaged Valve Fire Explosion Overfilled contents in cylinder Nitrous Oxide Theft Contaminated contents in cylinders Thermal Injury

65. Rules for safe use of cylinders To be handled by trained staff Store cylinders in a cool, clean room with adequate ventilation Do not drape cylinder with any material during storage Cylinders are best stored upright in a cylinder stand Keep the valve closed when not in use Remove protective covering before use Remove dust/ foreign bodies before connecting

66. Rules for safe use of cylinders Identify contents by label ‘ Cracking ’ a cylinder refers to opening valve slightly and closing it quickly to blow out dust or dirt from value outlet and port should be point away from the user and any other personal

67. Rules for safe use of cylinders Always open the valve slowly & before connecting to Anaesthesia machine:- If valve is opened fast gas passes quickly between valve & the yoke or regulator sudden recompression of the gas large amount of heat generated (Joule-Thompson effect) if any dust or grease in the space may be ignited by the heat fire & explosion,

68. Rules for safe use of cylinders Sudden release of gases Pressure gauge & regulator damage • Thus;- Valve should always be opened slowly, Opened before connecting to the anaesthesia mach. Never apply grease. Never keep the cylinder valve always open when the cylinder is not being used Slow depletion of gases from the cylinder when pipeline pressures drop down No reserve will be available i.c.o pipeline supply failure.

69. Rules for safe use of cylinders Identify contents by label ‘ Cracking ’ a cylinder refers to opening valve slightly and closing it quickly to blow out dust or dirt from value outlet and port should be point away from the user and any other personal i f gas passes quickly into the space between the valve and the yoke, the rapid recompression will generate a large amount of heat. This is an adiabatic process (heat is neither lost nor gained from environment). Particles of dust, grease present in this space may be ignited by heat, causing a flash fire or explosion. The valve should be opened slowly when attached to the anaesthesia machine or regulator.

70. Rules for safe use of cylinders Flow control valves should be closed before cylinders opened Quick opening to be avoided as it can generate heat leading to form flames Valve should be fully opened when in use To be kept away from oil, Rubber and combustible substances Do not expose cylinder to heat or higher temperatures

71. Safety Features of Cylinders Label of the cylinder and marking Seamless body Symbol of the gas on the cylinder valve Color coding and Safety relief devices Pin index safety system Molybdenum steel for stronger and lighter Bodak seal Cylinder pressure gauge indicator Tare weight and sizes

72. REFRENCES Understanding Anaesthetic Equipment & Procedures A Practical Approach,2015;Dwarkadas Baheti Understanding anaesthesia equipment and procedures ,south asian edition.5 th Edition Jerry A Dorsch and Susan E Dorsch

73. Thank You.