UNIT 6 DETERMINATION OF FLASH AND FIRE POINT OF A LUBRICATING OIL BY OPEN CUP AND CLOSED CUP METHODS Determinatin f Flash and Fire Pint f a Cup and Clsed Cup Structure 6. Intrductin Objectives 6. Experiment N. 5 : Determinatin f Flash Pint f a Lubricating Oil Using Cleveland s Open Cup Apparatus 6.. Principle 6.. Requirements 6.. Prcedure 6..4 Observatins 6..5 Calculatins 6..6 Result 6. Experiment N. 6 : Determinatin f Flash and Fire Pints in Lubricating Oil Using Pensky-Marten s Clsed Cup Apparatus 6.. Principle 6.. Requirements 6.. Prcedure 6..4 Observatins 6..5 Calculatins 6..6 Result 6. INTRODUCTION A gd lubricating il reduces the lss f energy in the frm f heat and it increases the efficiency f a machine. It shuld als nt vlatilize under the wrking temperatures. Even if the vlatilisatin takes place t sme extent, the vapurs frmed shuld nt frm inflammable mixtures with air under the cnditins f lubricatin. Therefre, the flash and fire pint f a lubricating il have a great imprtance. The flash pint is defined as the minimum temperature at which the il gives ff sufficient vapur that ignite fr a mment, when a flame is brught near it. While the fire pint is the lwest temperature at which the vapurs f the il burn cntinuusly fr at least five secnds, when a flame is brught near it. Since a gd lubricating il shuld nt vlatilise under wrking cnditins, s it shuld have flash pint abve the perating temperature in mst cases. Similarly, in mst cases, the fire pints are 5 t 40 F higher than the flash pints. But these fire and flash pints d nt have any bearing with the lubricating prperty f the il. Objectives After perfrming flash and fire pint analysis, yu shuld be able t define the flash and fire pints, explain the imprtance f flash and fire pints, discuss why flash pint shuld be abve the perating temperature, determine the flash pint and fire pints by clsed and pen cup methds, 49
Chemistry Lab Manual appreciate that flash and fire pint is helpful in prviding safeguards against fire hazards during their strage, transprtatin, handling and use, and detect slvent cntaminatin frm the use f flash and fire pints. 6. EXPERIMENT NO. 5 : DETERMINATION OF FLASH POINT OF A LUBRICATING OIL USING CLEVELAND S OPEN CUP APPARATUS 6.. Principle The flash and fire pints f a lubricating il may be determined by either pen cup r clsed cup apparatus. First, we will discuss abut the pen cup apparatus, in which the il is heated with its upper surface expsed t the atmsphere. Cleveland s pen cup apparatus (Figure 6.) is generally used fr determinatin f flash pint f fuel ils and ther ils having flash pint belw 75 F. 6.. Requirements Figure 6. : Cleveland s Flash Pint Apparatus Apparatus Quantity Chemicals Cleveland s flash pint Testing il apparatus Thermmeter Thermmeter stand Standard test flame device 50 6.. Prcedure The experimental prcedure invlves the fllwing steps : (i) The il cup has a marking inside t indicate the level up t which the cup is filled. The il cup is filled with the testing il upt the mark under rm temperature. (ii) Insert a thermmeter inside the il cup in such a way that the bttm f the thermmeter bulb is abut t cm abve the bttm f the cup. The thermmeter is clamped with thermmeter stand. (iii) Heat the apparatus electically slwly at the rate f t 5 C rise in temperature per minute.
(iv) (v) Watch the thermmeter very carefully and in every C rise in temperature, the standard test flame is brught near the surface f the il. Observe that whether a flash appears at any pint n the surface f the il. (vi) Nte the minimum temperature at which a distinct flash appears n the surface f the il in the cup as the flash pint f the il under test. Reapeat this experiment t get a cnstant value (Table 6.). 6..4 Observatins Table 6. : Flash Pint f Lubricating Oil Sl. N. Flash Pint (in t C) 6..5 Calculatins The mean value f the abve three experiments shuld be taken as : + + =... t C 6..6 Result The flash pint f given il sample =....... C. SAQ Define the flash and fire pints. Determinatin f Flash and Fire Pint f a Cup and Clsed Cup 6. EXPERIMENT NO. 6 : DETERMINATION OF FLASH AND FIRE POINTS IN LUBRICATING OIL USING PENSKY-MARTEN S CLOSED-CUP APPARATUS 6.. Principle In this experiment, yu will use Pensky-Marten s apparatus as shwn in Figure 6.. Test Flame Burner Openings Pilet Burner Shutter Cntrl Oil Level Pinter Air Bath Stirrer Oil Cup Figure 6. : Pensky-Marten s Apparatus This is the mst cmmnly used apparatus fr determinatin f flash and fire pints f ils having flash pints between 50 C t 70 C. The clsed cup apparatus gives mre reprducible results. The flash pint btained with clsed cup apparatus in generally abut 0 t 0 F lwer than that btained with an pen cup apparatus. 6.. Requirements Apparatus Quantity Chemicals Pensky-Marten s apparatus Testing il Bunsen burner Thermmeter 5
Chemistry Lab Manual 6.. Prcedure The experimental prcedure invlves the fllwing steps : (i) (ii) (iii) (iv) (v) (vi) Fill the il cup with the il t be tested upt the mark. Fix the cver n the tp. The cver itself cmprises the stirring device, the thermmeter and the flame expsure device. The test flame is lighted and adjust t abut 4 mm in diameter. Heat the apparatus by Bunsen burner slwly at the rate f 5 t 6 C per minute while the stirrer is rtated apprximately 60 revlutins per minute. At every C rise in temperature, intrduce the test flame fr abut secnds int the il vapur. This is dne by perating the shutter. By twisting the knb, the test flame is lwered and the shutter pens. The mment knb is released, the test flame springs back t its riginal psitin and the shutter is clsed. The flash pint is nted dwn when the test flame causes a flash in the interir f the cup (Table 6.). Repeat it three times t get a cnstant value r take a mean value. (vii) Further heat the test il at the rate f C rise in temperature per minute and cntinue applying the test flame as in pint (v) abve. (viii) The temperature at which the vapurs f the il give a clear and distinct blue flash fr five secnds is recrded as the fire pint f the il, (Table 6.). Repeat it t get a cnstant value r take a mean value. 6..4 Observatins Table 6. : Flash Pint f a Lubricating Oil Sl. N. Flash Pint in C Table 6. : Fire Pint f a Lubricating Oil Sl. N. Fire Pint in C 5 6..5 Calculatins The mean value f flash pint is + + =... C The mean value f fire pint is + + =... C 6..6 Result The flash pint f given lubricating il is =...... C. The fire pint f given lubricating il is =....... C.
CHEMISTRY LAB MANUAL Learning by ding is always enjyable and lnger lasting. With this fcus in mind, this cmpnent f the chemistry lab has been designed. There are in ttal 6 experiments which have been arranged in 6 units. Unit cntains three experiments related t inrganic and rganic analyses. Unit is devted t the preparatin f acetylene gas and testing its acidic nature. Unit cntains fur experiments which invlve the determinatin f parameters related t water quality f water and waste water. These include ttal hardness, permanent and temprary hardness, BOD and chlride cntent. Unit 4 describes three experiments related t the determinatin f dsage f bleaching pwder required fr disinfectin f water, desalinatin f water and determinatin f ph. The study f these parameters help in the treatment f raw water which can be used fr drinking. In Unit 5, there are three experiments related t the determinatin f viscsity, density and carbn residue f a lubricating il. These types f determinatin help in selecting a prper lubricant fr a specific purpse. There are tw mre experiments related t the efficiency f a particular lubricating il which invlve the determinatin f flash and fire pints. These experiments frm part f Unit 6. The details f all these experiments have been included in this manual. G thrugh these befre actually perfrming the experiments. We hpe that yu enjy the wrking in the labratry. Determinatin f Flash and Fire Pint f a Cup and Clsed Cup 5