延长压缩空气系统中储气罐使用寿命的措施及方法

在压缩空气系统中,储气罐作为储存系统压缩空气、减小系统压缩空气压力波动的重要特种设备,其设计寿命一般为10年。在日常使用过程中,如果工作环境过于恶劣、操作不规范、不定期保养维护,不但容易导致故障的发生,而且也会缩短其使用寿命。良好的工作环境、操作习惯及科学合理的保养周期都可以在一定程度上延长其使用寿命。本文针对影响储气罐使用寿命的外部因素及提高储气罐使用寿命的措施进行讨论。     

多台空气压缩机减荷阀控制措施

我公司使用柳州生产的ZW 3/7型无油润滑空气压缩机 ,在正常工作时 ,空气进入压缩机后 ,经压缩送到储气罐 ,当压力达到设定上限值时 ,压缩空气通过压力调节阀控制减荷阀 ,把气门关闭 ,空气压缩机不再压缩空气 ,压力不再升高 ,当气压下降到设定的下限值时 ,将气门打开。在使用过程中 ,由于我公司用气量较大 ,需要多台空气压缩机同时工作 ,才能达到生产用气量的要求。而每台空气压缩机都有独立的压力调节阀控制 ,各台的压力调节阀开启压力不可能一致 ,所以造成一台或两台空气压缩机长期处于不工作状态 ,有的机台则长期工作 ,各台负荷不均匀 ,…     

压缩空气带水的解决方法

压缩空气带水可由多种原因引起，既有工艺设计不合理引起，也有操作不当的原因；既有设备本身的结构问题，也有设备及控制元件的技术水平问题。本文根据我厂的生产实际，探讨了各种情况的对策──压缩空气带水的解决方法。     

自由浮球式空气疏水阀

为了排放掉压缩空气系统管网、储气罐(包)里的油污和水,须人工定时手工排放。由于责任心和其他原因,延误排放的情况时有发     

确保面粉车间压缩空气的质量和压力的重要性

阐述确保面粉车间压缩空气的质量和压力的重要性,提出避免因压缩空气质量差和气压不足而导致电磁阀堵塞、气力输送系统瘫痪、部分磨粉机磨辊相互碰撞等问题的解决方案。     

通过设备工艺参数设定,降低包装车间能耗

本文介绍了包装车间从设备、工艺参数设定上降低能耗的一些做法,供大家参考。啤酒生产用能源有蒸汽、空压、水、CO₂、冷媒、电力等,通过设备、工艺参数设定,可降低设备故障率,节约能耗。1卸箱机、装箱机抓头通过充放气,将啤酒瓶抓起,输送到瓶台或塑料（纸）箱内,如压缩空气不控制压力,会在随     

浅析冷冻式干燥机高故障率的产生原因和防范措施

火力发电厂中的压缩空气系统主要有仪表用压缩空气系统、工厂杂用压缩空气系统、水处置压缩空气系统和除灰用压缩空气系统。冷冻式干燥机是压缩空气系统重要的配套设备,目的是提高压缩空气质量,减少压缩空气中的水分,防止经过压缩冷凝后的湿饱和空气,夹带大量的的液态水滴对设备、管道和阀门、仪器、仪表产生相当的危害,从而降低设备的寿命,这对于追求高可靠性的自动化生产线无疑是一种危险。因此防止冷冻式干燥机发生故障,减少高故障是非常有必要的。     

3L-10/8型空压机改造

我厂使用的3Ｌ-10/8型空压机为Ｌ型二级双缸复动水冷式,使用压力范围是0.4～0.8ＭＰａ,排气量为10ｍ3/ｍｉｎ。在使用过程中发现,空压机的曲轴箱与二级气缸串油,过油量大。在储气罐的排污管放出大量的污油,严重影响了压缩空气的质量,并且加油周期缩短(3小时加一次油,每次加20ｋｇ),造成巨大浪费。车间与生产技术部门积极配合,果断决定对其进行解体鉴别,分析原因,找出解决办法。1　原因的分析①解体后发现,二级缸座与密合圈的接触面磨损,有明显的痕迹,用手触摸,有凹凸不平的感觉。②空压机经多年使用后,刮油环的内孔磨损较大,出现了拉伤失圆,…     

胶合板车间空气压缩机站及其管路设计

目前用压缩空气作动力源的设备不断增加。特别是近年来由国外引进的胶合板设备,压缩空气的应用更加广泛。例如:由芬兰、日本进口的旋切机的防弯装置、单板卷大卷装置、单板气动切断机、横向拼缝机和宽带砂光机等很多设备都用压缩空气作部分动力源或全部动力源。随着木材加工企业生产自动化水平的不断提高,生产车间内现有的多台小型空压机、即存在浪费电力和人力、不安全、噪声大和不便管理等缺点,又很难保证设备的供气量和供气压力。在木材加工企业中,采用大型空气压缩机站统一向各用气设备供应充足的气体和足够的压力是保     

蒸汽冷凝水热量的回收

我们通过能源调查、实际测定和热平衡计算，发现占全厂用汽量75％左右的造纸车间节能潜力较大。特别是有的厂将蒸汽冷凝水全部排入阴沟，没有将热量充分利用。在一定压力下的饱和蒸汽冷凝水释放到大气中，由于压力下降，显热变小，使部分水蒸发，形成所谓“二次蒸汽”，还由于疏水器故障和操作上的原因，也会带出部分蒸汽。现通过一只热交换器，将这两部分蒸汽加以回收利用，取得了较好的效果。将造纸车间造纸机烘缸出口处疏水器排出的蒸汽冷凝水全部汇集到一只贮水箱中，其工艺流程详见下图。该回收装置内装有盘管式热交换器，自来水（冷水…     

Ermittlung der Sorptionsisothermen von Holzwerkstoffen bei verschiedenen Temperaturen mit einem neuen Meßverfahren

To determine sorptional isotherms of wood based materials at various temperatures, a new computer aided measuring system has been developed. By this method, the equilibrium moisture contents at various temperatures are reached within 8 hours already. Here, instead of adaptation of specimen's moisture content to constant air humidities, the adaptation of air humidity to the specimen's constant moisture content is measured. The specimens whose moisture contents are gravimetrically determined are placed in air-tight containers, with climate recorded by sensors for temperature and moisture. The containers themselves are situated in climate chambers, there measurements are carried out at temperatures between ?20°C and 60°C.     

集聚纺节能的研究

在网格圈的空气阻力规律上,提出“加大网孔,降低负压,减小能耗”的理论依据,阐明了低能耗网格圈的节能原理和低能耗型集聚纺的构思;借助分散组件的短负压管形成本锭位范围内的空气回流,不会形成车间内的“负压区”,改变了车间原有空气循环状态,有助于减少车间灰尘量,也不会增加车间空调负担.     

通风过程中进风相对湿度对仓储粮堆温度和水分的影响研究

温度和水分含量是两个重要的物理变量,在研究谷物储存时品质变化起到很大作用。通风用于冷却粮堆并保持温度恒定,以防止水分迁移。良好的通风条件对粮仓内存储安全有显著影响。目前,通风空气相对湿度对粮堆水分影响的研究相对较少。采用数值模拟和实验研究相结合的方式,探索和比较因不同进风相对湿度而引起的通风过程中仓储的小麦温度和水分变化规律。结果表明:进风相对湿度较低时冷却干燥效率更高,小麦粮堆降温更快速,并将昆虫和霉菌的活动保持在较低水平。     

空调控温技术在高大平房仓储藏偏高水分稻谷中的应用实践

本文应用空调控温技术开展了高大平房仓储藏偏高水分稻谷(15.5％)和正常水分稻谷(14.2％)的对比试验.结果 表明:在储藏期间,采用空调控温技术能有效控制仓温和上层粮温,稻谷的储存品质指标均符合"宜存"要求,且由于偏高水分稻谷的含水量较高,合理保持了储粮水分,其加工品质优于正常水分稻谷,实现稻谷的安全保质储藏和仓储企...     

棉织物干燥过程热湿传递特性软件计算与分析

以单层多孔薄棉织物为对象,分析并建立其热风干燥过程中的热质传递机理及数学模型,得到织物在烘干过程中含水率与温度的变化规律,并采用MATLAB APP designer设计了棉织物传热传质数值计算软件,简易又直观地显示了各干燥段干燥时间与温湿度变化曲线。结果表明,薄棉织物在干燥过程中,内部温度与含水率的梯度基本可忽略不计,薄棉织物恒速段干燥时间占总时间的70%以上,但在结束恒速干燥段后内部仍有一定的吸附水含量。可为印染热定形机的风道结构设计和棉织物热定形工艺参数的设定提供理论参考价值。     

True Thermal Conductivity Determination of Moist Porous Food Materials at Elevated Temperatures

Thermal conductivity (k) of bread samples, moisture content 5% to 44%, (w/w, wet basis) and porosity 0.18 to 0.90, was measured in a sealed stainless steel vessel using the probe method from 25 to 85°C. Significant differences were observed in measured thermal conductivity before and after air pressure was applied to the sample indicating the influence of vapor phase moisture migration on thermal conductivity. The difference increased as temperature and moisture content were increased. True thermal conductivity of bread was found to agree with predictions using a volume fraction model when moisture migration was completely suppressed at an applied air pressure of 18 atm.     

Effect of expansion by instantaneous controlled pressure drop on dielectric properties of fruits and vegetables

The instantaneous controlled pressure drop (DIC) treatment is used for creation of a porous structure during drying of fruits and vegetables. DIC is based on high temperature, short time heating followed by an abrupt pressure drop into a vacuum. This abrupt pressure drop provokes auto-vaporization of the superheated liquid, expansion and breaking of the cell walls and instantaneous cooling. This process step is inserted between two drying stages at a moisture content of about 20% wet basis. The use of microwave radiation would provide more rapid and homogeneous heating than using steam in the DIC treatment and hot air during the final stage of drying. For that purpose the dielectric properties of the raw and DIC treated products were measured. The measurements were carried out with an open-ended coaxial probe at a frequency of 915 MHz in the range of temperatures 20-90 °C and moisture content 5-80% w.b. Three regions were revealed for the dependences of the dielectric constant and loss factor on moisture content. At low moisture content, these properties increased linearly with moisture content. At the middle moisture content, the increase was also linear but much steeper. At high moisture content, the dielectric properties were constant. The limits of these regions were different for ε′ and ε″ as well as for the products. The dielectric properties were slightly temperature dependent. The penetration depth increased with decreasing moisture content. The DIC treated products exhibited slightly lower dielectric properties than the raw products.     

SIMULATION OF THE EVAPORATIVE COOLING PROCESS FOR TORTILLAS

A simulation model was developed to predict temperature, moisture content and water activity of evaporatively cooled tortillas. The overall model was based on three parts: (1) the predicted equilibrium moisture isotherm for the product, (2) a correlation model for predicting the saturated water vapor pressure for a given temperature, and (3) the energy and mass balances for simultaneous convective heat and moisture transfer between product and cooling air. The simulation model was verified with experimental data and was found to accurately describe the behavior of the tortilla cooling system. The model predicted the simultaneous decrease in temperature, moisture content, and water activity of the product exposed to varying simulated processing conditions. It was found that cooling air velocity and temperature had the primary effect on product cooling and moisture loss rates.     

DETERMINATION OF OIL POINT PRESSURE FOR MELON SEEDS

The oil point pressure of melon seed oil at different processing conditions, i.e., preheating moisture content (6.6, 8.3, 10.0 and 12.0% wet basis [w.b.]), heating temperature (70, 85, 100 and 115C) and heating time (15, 20, 25 and 30 min), was determined. The postheating moisture content increased with an increase in preheating moisture content and decrease in heating temperature and time. The oil point pressure obtained varied from 0.84 MPa for a moisture content of 6.6% (w.b.) heated for 30 min at 100C to 2.05 MPa for a moisture content of 12.0% (w.b.) heated for 15 min at 70C. The oil point pressure increased with increase in preheating moisture content and decreased as the heating temperature and time increased from 70 to 100C and from 15 to 25 min, respectively. A further increase in heating temperature to 115C and heating time to 30 min, however, increased the oil point.

PRACTICAL APPLICATIONS

Melon seeds are one of the commonly available oilseeds with a high oil content, and their high oil content makes them valuable for oil production. The optimization of the expression process through the identification of the oil point pressure of melon seeds is necessary for the effectiveness/efficiency of the process. The maximum oil point pressure (2.05 MPa) was obtained from the lowest value of heating temperature (70C) and time (15 min) and the highest moisture content (12.0% wet basis), while the minimum value (0.84 MPa) was from high heating temperatures and time and the lowest preheating moisture content. These indicate that reduced heat treatment of melon seeds increases the pressure required for expression, thus reducing process efficiency and increasing production cost.     

Fish oil microencapsulation as influenced by spray dryer operational variables

The effects of spray‐drying air temperature, aspirator rate (drying air mass flow rate), peristaltic pump rate (feed mass flow rate) and spraying air mass flow rate on microencapsulation properties of fish oil including moisture content, particle size, bulk density, encapsulation efficiency and peroxide were investigated. The process was carried out on a mini spray dryer, and skim milk powder was used as the encapsulating wall material. Results indicated that increasing inlet air temperature increased the particle size, encapsulation efficiency and peroxide value but decreased the bulk density and moisture content of product. Increasing aspirator rate resulted in increased particle size and peroxide value but decreased the moisture content and bulk density. Increase in feed mass flow rate increased the moisture content, particle size, bulk density and peroxide value but decreased the encapsulation efficiency of microcapsules. The encapsulation efficiency and bulk density increased with the increasing aspirator rate but moisture content, particle size and peroxide value decreased.