검색어: high grade obstruction (영어 - 페르시아어)

high grade .
درجه اعلي .

2048 (high grade)
۲۰۴۸) درجۀ بالا (

high grade paper
کاغذ درجۀ بالا

dr murdoch, peter's developed a high-grade fever and a cough.
دكتر مورداك ، پيتر به شدت تب داره و سرفه ميكنه

for prints on high grade fibre papers, a period of continuous washing in clean, cold water for up to 40 minutes may be required.
در چاپ کاغذهای کنتراست بالا که پایه فیبری دارند، ممکن است یک دوره شستشوی مداوم ۴۰ دقیقه‌ای با آب سرد و تمیز لازم باشد.

once a good clean crystal crop is established, it is desirable to reduce syrup feed and allow the oversaturation to rise into the 60 to 65% range for rapid grain growth. as crystal yield increases, the massecuite consistency will increase and after a time, will reach a good boiling consistency with 15% to 20% crystals on total solids. it is during this phase of sugar boiling that a great many otherwise excellent strikes are irreparably spoiled. a sugar boiler likes to tighten a strike as soon as possible because a tight strike is a safe one; there is plenty of crystal surface to absorb all the sugar that can be made available by boiling and he can relax and just feed to keep the massecuite consistency within bounds but if the tightening process is done too rapidly before sufficient crystal area has been produced, the syrup can easily reach excessive levels of oversaturation and a second crop of crystals will form. they can only be melted out by adding enough water to make the syrup undersaturated and waiting until they completely dissolve, but this is costly in terms of time and steam. if the strike is continued, the crystal size will be mixed and produce an inferior massecuite. by watching the oversaturation monitor and keeping it high, but on the safe side of the 65% limit, tightening can be accomplished in minimum time without additional grain formation and an excellent strike is on its way. when boiling consistency is reached, it is maintained by regulating feed until the pan is full, at which time, the oversaturation will have slowly fallen to the 40 or 50% level. final tightening when maximum massecuite level is reached and syrup feed is shut off, all the water being evaporated must come from the mother liquor syrup so the oversaturation will rise slowly and it must not be allowed to exceed a safe limit or some fine grain will form and, although their presence may not hinder centrifugal separation too much, the pan yield will be reduced; most of the fine crystals will pass through the centrifugal screens and be lost in the molasses and some will adhere to the good crystals and can cause a dust problem when dried. during final brining, it is most desirable to deposit the available sugar on the existing crystals; this is the time of greatest sugar production in the pan cycle so a few extra minutes taken to brix up are well spent. if it appears that oversaturation will reach an unsafe limit during this critical stage, then reduce the evaporating by cutting steam flow or introducing some water feed. the latter is preferable as it maintains circulation. increasing crystal yield during final tightening does not appreciably affect the mother liquor purity in high-grade strikes but in those of lower purity, it is necessary to use some judgment in determining the safe limit of syrup concentration. refinery syrups at 99 purity would only drop to 98 purity at a final yield of 50% solids in crystal form and, if the monitor zero had been correctly set during the early stages when crystal yield was low, the oversaturation should not go above 65%. before dropping low grade strikes, the mother liquor purity will have fallen below that of the massecuite but generally in these strikes the yield is not high at pan drop; most of the yield will come out in the crystallizers. for example, a 65 purity cane c strike might only have 20% yield when dropped so the mother liquor would be 54 purity. by setting the monitor zero dial over this range it is seen to make 12% oversaturation change. so leaving zero set at 65 purity the indication just before dropping could be allowed to go into the red zone but not over 77% oversaturation. a typical beet white strike with 93 purity standard liquor will have around 40% crystal yield when dropped and it will increase in the mixer to around 55% or better. but when dropped at the end of brining the mother liquor will be around 88 purity. the five point drop from massecuite purity amounts to about 8% increase in oversaturation so it has been verified many times that in the final moments before dropping, fine grain will begin to appear if the pointer gets above 73% oversaturation. the maximum increase in oversaturation reading that can be tolerated during final tightening can be easily determined by frequent microscope examinations of the first few strikes boiled on a particular syrup. once it is determined, the sugar boiler need only stay below the limit during that period. actually, if good boiling has been done during preceding portions of the cycle, the oversaturation will seldom rise to an unsafe level during the final stage; the crystal area is increasing rapidly and the boiling rate is falling as the consistency increases so it will generallybe observed that the reading rises slowly, levels off and begins to fall before the end of the strike. the crystallization rate decreases with syrup purity even at the same oversaturation so on lower grade strikes, high oversaturations are held during a large part of the cycle. when feed syrups are quite concentrated, the pan may fill before crystals have had time to grow to proper size for good centrifugal separation. it is wise to prolong the pan cycle under these circumstances by reducing syrup feed and supplementing with some water feed to maintain oversaturation at a high but safe value. it is better to boil rapidly to keep good massecuite once a good clean crystal crop is established, it is desirable to reduce syrup feed and allow the oversaturation to rise into the 60 to 65% range for rapid grain growth. as crystal yield increases, the massecuite consistency will increase and after a time, will reach a good boiling consistency with 15% to 20% crystals on total solids. it is during this phase of sugar boiling that a great many otherwise excellent strikes are irreparably spoiled. a sugar boiler likes to tighten a strike as soon as possible because a tight strike is a safe one; there is plenty of crystal surface to absorb all the sugar that can be made available by boiling and he can relax and just feed to keep the massecuite consistency within bounds but if the tightening process is done too rapidly before sufficient crystal area has been produced, the syrup can easily reach excessive levels of oversaturation and a second crop of crystals will form. they can only be melted out by adding enough water to make the syrup undersaturated and waiting until they completely dissolve, but this is costly in terms of time and steam. if the strike is continued, the crystal size will be mixed and produce an inferior massecuite. by watching the oversaturation monitor and keeping it high, but on the safe side of the 65% limit, tightening can be accomplished in minimum time without additional grain formation and an excellent strike is on its way. when boiling consistency is reached, it is maintained by regulating feed until the pan is full, at which time, the oversaturation will have slowly fallen to the 40 or 50% level. final tightening when maximum massecuite level is reached and syrup feed is shut off, all the water being evaporated must come from the mother liquor syrup so the oversaturation will rise slowly and it must not be allowed to exceed a safe limit or some fine grain will form and, although their presence may not hinder centrifugal separation too much, the pan yield will be reduced; most of the fine crystals will pass through the centrifugal screens and be lost in the molasses and some will adhere to the good crystals and can cause a dust problem when dried. during final brining, it is most desirable to deposit the available sugar on the existing crystals; this is the time of greatest sugar production in the pan cycle so a few extra minutes taken to brix up are well spent. if it appears that oversaturation will reach an unsafe limit during this critical stage, then reduce the evaporating by cutting steam flow or introducing some water feed. the latter is preferable as it maintains circulation. increasing crystal yield during final tightening does not appreciably affect the mother liquor purity in high-grade strikes but in those of lower purity, it is necessary to use some judgment in determining the safe limit of syrup concentration. refinery syrups at 99 purity would only drop to 98 purity at a final yield of 50% solids in crystal form and, if the monitor zero had been correctly set during the early stages when crystal yield was low, the oversaturation should not go above 65%. before dropping low grade strikes, the mother liquor purity will have fallen below that of the massecuite but generally in these strikes the yield is not high at pan drop; most of the yield will come out in the crystallizers. for example, a 65 purity cane c strike might only have 20% yield when dropped so the mother liquor would be 54 purity. by setting the monitor zero dial over this range it is seen to make 12% oversaturation change. so leaving zero set at 65 purity the indication just before dropping could be allowed to go into the red zone but not over 77% oversaturation. a typical beet white strike with 93 purity standard liquor will have around 40% crystal yield when dropped and it will increase in the mixer to around 55% or better. but when dropped at the end of brining the mother liquor will be around 88 purity. the five point drop from massecuite purity amounts to about 8% increase in oversaturation so it has been verified many times that in the final moments before dropping, fine grain will begin to appear if the pointer gets above 73% oversaturation. the maximum increase in oversaturation reading that can be tolerated during final tightening can be easily determined by frequent microscope examinations of the first few strikes boiled on a particular syrup. once it is determined, the sugar boiler need only stay below the limit during that period. actually, if good boiling has been done during preceding portions of the cycle, the oversaturation will seldom rise to an unsafe level during the final stage; the crystal area is increasing rapidly and the boiling rate is falling as the consistency increases so it will generallybe observed that the reading rises slowly, levels off and begins to fall before the end of the strike. the crystallization rate decreases with syrup purity even at the same oversaturation so on lower grade strikes, high oversaturations are held during a large part of the cycle. when feed syrups are quite concentrated, the pan may fill before crystals have had time to grow to proper size for good centrifugal separation. it is wise to prolong the pan cycle under these circumstances by reducing syrup feed and supplementing with some water feed to maintain oversaturation at a high but safe value. it is better to boil rapidly to keep good massecuite circulation and feed water than to reduce steam flow.
هنگامی که یک محصول کریستال تمیز خوب ایجاد شد، مطلوب است که خوراک شربت کاهش یابد و اجازه داده شود که اشباع بیش از حد به محدوده 60 تا 65 درصد برای رشد سریع دانه افزایش یابد. با افزایش بازده کریستال، قوام ماسکوییت افزایش می یابد و پس از مدتی به قوام جوش خوبی با 15 تا 20 درصد کریستال روی کل مواد جامد می رسد. در این مرحله از جوشاندن شکر است که بسیاری از ضربات عالی به طور غیر قابل جبرانی خراب می شوند. دیگ قند دوست دارد به محض اینکه ضربه را محکم کند