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中文名 沥青Chinese name asphalt CAS登录号8052-42-4The CAS login number 8052-42-4 EINECS登录号232-490-9EINECS registration number 232-490-9 熔 点 485Melting point 485 沸 点 <470℃Boiling point < 470 ℃ 水溶性不溶于水Water soluble does not dissolve in water 密 度 1.15-1.25Dense degree of 1.15 to 1.25 外 观半固体或液体状态Outside view half solid or liquid state 闪 点204.4Flash point 204.4 危险性描述健康危害:中等毒性Describe health hazard risk: medium toxicity 来 源煤和石油To the source of coal and oil 成 分沥青质和树脂Into asphaltene and resin 含 量99.48%Containing 99.48% 爆炸下限 30(g/立方厘米)The lower explosive limit (30 g/cm3) 导电性能绝缘体(常温下)Conductivity insulator (room temperature) 沥青属于憎水性材料,它不透水,也几乎不溶于水、丙酮、乙醚、稀乙醇,溶于二硫化碳、四氯化碳、氢氧化钠。沥青及其烟气对皮肤粘膜具有刺激性,有光毒作用和致癌作用。我国三种主要沥青的毒性:煤焦沥青>页岩沥青>石油沥青,前二者有致癌性。沥青的主要皮肤损害有:光毒性皮炎,皮损限于面、颈部等暴露部分;黑变病,皮损常对称分布于暴露部位,呈片状,呈褐-深褐-褐黑色;职业性痤疮;疣状赘生物及事故引起的热烧伤。此外,尚有头昏、头胀,头痛、胸闷、乏力、恶心、食欲不振等全身症状和眼 、鼻、咽部的刺激症状。Asphalt is hydrophobic material, it impermeable, almost insoluble in water, dilute ethanol, acetone, ether, soluble in carbon disulfide, carbon tetrachloride, sodium hydroxide.Asphalt and flue gas of skin mucous membrane irritation, has the light effect and the effect that cause cancer.China's three major asphalt toxicity: coal tar > > oil shale asphalt asphalt, before both have carcinogenicity.The main skin lesions are: asphalt light contact dermatitis, skin confined to the face, neck and other exposed parts;Melanosis, skin lesions often symmetrical distributed in the exposed parts, plate shaped, brown - deep brown - brown-black;Occupational acne;Verrucous vegetations and the accident cause thermal burns.In addition, there are dizziness, head bilges, headache, chest tightness, fatigue, nausea, loss of appetite and other systemic symptom and eye, nose, pharynx and irritation. 煤焦沥青Coal tar: 煤焦沥青是炼焦的副产品,即焦油蒸馏后残留在蒸馏釜内的黑色物质。它与精制焦油只是物理性质有分别,没有明显的界限,一般的划分方法是规定软化点在26.7℃(立方块法)以下的为焦油,26.7℃以上的为沥青。煤焦沥青中主要含有难挥发的蒽、菲、芘等。这些物质具有毒性,由于这些成分的含量不同,煤焦沥青的性质也因而不同。温度的变化对煤焦沥青的影响很大,冬季容易脆裂,夏季容易软化。加热时有特殊气味;加热到260℃在5小时以后,其所含的蒽、菲、芘等成分就会挥发出来。Coal
tar is a by-product of coking, namely tar distillation residue in distillation
kettle black material.It has respectively with refined tar is only physical
properties, there is no clear boundaries, is the way of dividing rules softening
point in commonly 26.7 ℃ (cube method) for tar, under 26.7 ℃ above for asphalt.Coal
tar mainly contains difficult volatilization of anthracene, phenanthrene, pyrene,
etc.These substances have toxic, because the content of these compounds is
different, the properties of coal tar are so different.The change of temperature
has much effect on the coal tar, winter easy embrittlement, summer is easy
to soften.Heating from time to tome special smell;Heated to 260 ℃ after 5 hours,
its composition such as anthracene, phenanthrene, pyrene will evaporate. ●高粘度齿轮泵并不能产生压力,它只是输出流量。压力低或无压力,说明高粘度齿 轮泵没有吸入液体或泄漏严重。 High viscosity gear pump does not generate pressure, it is only the output flow.Pressure is low or no pressure, high viscosity gear wheel pump don't inhale the liquid or leakage is serious. 电动机输出功率偏小、齿 轮泵排量选得过大或压力调得过高时,也会造成压力不足 当然,压力表损坏或压力表节流孔堵塞时也显示不出压力,此时可换装一个新的压力表检查。 Small motor output power, gear wheel pump capacity to choose too large or pressure too high, can cause stress Pressure gauge damage or pressure gauge orifice jams, of course, also could not show pressure, can change a new pressure gauge to check at this time. 如果确认泵无流量输出,可能是由于泵安装有误、泵的转向不对,或吸人侧 ( 进液口及吸液管道 ) 堵塞、出口止回阀装反或卡死了,也有可能是驱动轴断裂了。 If confirmed that no flow pump output, could be turned to the pumps due to pump installation is wrong, wrong, or suction side (liquid into the mouth and suck liquid pipeline jam, export check valve installed backwards, or card is dead, it is possible that the drive shaft fracture. 高粘度泵在转速过低时会引起出液量不足,这种现象往往是由于泵的驱动装置打滑或功率不足所致。此时应检查齿 轮泵的实际转速、泵与电动机的联接及功率匹配情况等。
High viscosity pump in low speed can cause insufficient quantity of produced
liquid, this phenomenon is often due to the slippage of the pump drive or insufficient
power.Check the gear wheel pump at this time of the actual speed, pump and
motor connection and power matching, etc. 高粘度齿轮泵的吸油管道内径应足够大,并避免狭窄通道或急剧拐弯、减少弯头,去除不必要的阀门、附件,尽可能地降低泵的安装高度,缩短吸油管道的长度,以减少压力损失。管接头等元件的密封要良好,以防止空气侵入,从而控制气穴与气蚀的发生。止回阀与安全阀在齿轮泵的输出管路上最好安装一个止回阀。这样在检修泵及输出管道时,系统中的液体不会发生倒流。齿轮泵带负荷停车时,亦可防止泵倒转而在其输出管道内产生局部真空。应当注意,出口止回阀不能装反或出现卡死现象。高粘度泵的出口管路上还应当设置安全阀等保护装置,这样一旦泵的出口通道发生堵塞,就可以打开安全阀卸压。安全阀可以与泵体或泵盖铸成一体,也可以单独装配。对于需要正反转的高粘度齿轮泵,其进出口管路上均需设置安全阀。
High viscosity gear pump oil suction pipe diameter should be large enough,
and to avoid the narrow channel, or a sharp turn, reducing elbow, remove unnecessary
valves, fittings, as much as possible to reduce the installation height of
pump, shorten the length of the oil suction pipe, in order to reduce the pressure
loss.Components, such as pipe joint sealed well, in order to prevent the air
intrusion, thus control air-pocket and the occurrence of cavitation.Check valve
and relief valve on the output of the gear pump tube had better install a check
valve.In the overhaul pump and output pipe, the system of fluid backflow will
not occur.Gear pump to stop loading machine, can be in the output pipe to prevent
pump reverse, and create a partial vacuum.It should be noted that the outlet
check valve cannot be installed backwards or stuck.High viscosity of the pump
outlet pipe also shall set up relief valve or other protective device on the
road, so that once the clogging pump export channels, can open the relief valve
pressure relief.The relief valve can be cast and pump body and pump cover,
also can separate assembly.For high viscosity gear pump need positive &negative,
import and export all needs to set up the line safety valve.
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