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摘yao:<p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> <br /> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> wen湿du试验箱的选zefang法<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;<a href="http://www.weihuang18.net/goodsid/goodsview/9716642.html" target="_blank">&nbsp;wen湿du试验箱</a>又名hengwenheng湿试验箱,高低wen交变湿热试验箱。wen湿du试验箱是电子业、光电业、汽机车业、电子系统厂、电子ling配jian、汽车电讁in⑴缤恳怠⑸萍肌⒅埔┮怠⒐鷔i、军工、航空、新能源等产业领域必备的测试she备,用于测试和确定电工、电子及qi他及材liaojin行高wen、低wen、交变湿热du或heng定试验的wendu环jing变化后的can数及xing能<span style="font-family:'Times New Roman';">.</span><span style="font-family:宋ti;">制造执行及符合标准</span><span style="font-family:'Times New Roman';">GB/T5170.5-2008</span><span style="font-family:宋ti;">湿热试验she备fang法</span>/GB/T10586-2006<span style="font-family:宋ti;">湿热试验箱技术条jian</span>//GB/T2423.1-2008<span style="font-family:宋ti;">试验</span><span style="font-family:'Times New Roman';">A</span><span style="font-family:宋ti;">低wen试验fang法</span>/GB/T2423.2-2008<span style="font-family:宋ti;">试验</span><span style="font-family:'Times New Roman';">B</span><span style="font-family:宋ti;">高wen试验fang法</span>/GB/T2423.3-2006<span style="font-family:宋ti;">试验</span><span style="font-family:'Times New Roman';">Ca</span><span style="font-family:宋ti;">heng定湿热试验fang法。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> <span style="font-family:宋ti;"><img src="http://zt.yzimgs.com/comfolder/331993/image/201408/20140802160809_9056.jpg" alt="" /><br /> </span> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;wen湿du试验箱是一款专业xing很强的试验测试仪qi,如he选ze一款合蕇hi慕枪愦笥没uyao考虑的问题。买球app试验she备小编今天在这儿给您小小的建议如xia几个fang面。<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> 一、容积的选ze(生产测试用还是研fa测试用)<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;将被试(元qijian、zujian、bujian或zheng机)置入wen湿du试验箱jin行试验蔮ao薭ao证被试周围气氛能满足试验规范所规定的环jing试验条jian,气候箱工作chicun与被试外廓chicun之间ying遵循yixia几点规定:<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;1.<span style="font-family:宋ti;">被试的ti积(</span><span style="font-family:'Times New Roman';">W</span><span style="font-family:宋ti;">×</span>H×D)bu得超过试验箱有xiao工作空间的(70<span style="font-family:宋ti;">~</span>80)%(推荐选用75%)。对于在试验中fa热的推荐选用bu大于60<span style="font-family:宋ti;">%。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;2.<span style="font-family:宋ti;">被试的yingfeng断面积与gai断面上试验箱工作室总面积之比bu大于(</span><span style="font-family:'Times New Roman';">35</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">50</span><span style="font-family:宋ti;">)%(推荐选用</span><span style="font-family:'Times New Roman';">35</span><span style="font-family:宋ti;">%)。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;3.<span style="font-family:宋ti;">被试外廓表面距试验箱壁的距离至少baochi</span><span style="font-family:'Times New Roman';">100</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">150mm</span><span style="font-family:宋ti;">,(推荐选用</span><span style="font-family:'Times New Roman';">150mm</span><span style="font-family:宋ti;">)。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> 上述san点规定shi际上是相huyi存和统一的。yi<span style="font-family:'Times New Roman';">1</span><span style="font-family:宋ti;">立fangmi正fangti箱子为li,</span>测试占箱ti容积3/4<span style="font-family:宋ti;">面积。</span>作出这种规定的li由是因为被试验jian置入箱ti后挤占了流chang的通dao,通dao变窄将导致气流流速的增紋in<铀倨饔氡皇匝閖ian之间的热交换。这与环jing条jian的再现bu符,因为在有关标准中对涉及wendu环jing试验都规定试验箱na试验样jian周围的空气流速buying超过<span style="font-family:'Times New Roman';">1.7m/s</span><span style="font-family:宋ti;">,yi防止试验样jian和周围气氛产生bu符合shi約hi娜却肌T诳赵豷hi试验箱na平junfeng速为</span><span style="font-family:'Times New Roman';">0.6</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">0.8m/s</span><span style="font-family:宋ti;">,bu超过</span><span style="font-family:'Times New Roman';">1m/s</span><span style="font-family:宋ti;">,满足</span><span style="font-family:'Times New Roman';">a</span><span style="font-family:宋ti;">)、</span><span style="font-family:'Times New Roman';">b</span><span style="font-family:宋ti;">)liang点yao求所规定的空间及面积比蔮ao鞒〉膄eng速可能增大(</span><span style="font-family:'Times New Roman';">50</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">100</span><span style="font-family:宋ti;">)%,平jun*高feng速为(</span><span style="font-family:'Times New Roman';">1</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">1.7</span><span style="font-family:宋ti;">)</span><span style="font-family:'Times New Roman';">m/s</span><span style="font-family:宋ti;">。满足标准规定的yao求。如果在试验中bu加限制di加大试验jian的ti积或yingfeng断面积,则shi际试验shi气流feng速将增大到超出试验标准所规定的*高feng速,qi试验结果的有xiaoxing将shou到怀yi。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;二、控制fang式的选ze:(heng定wen湿du和wen湿du交变<span style="font-family:'Times New Roman';">-</span><span style="font-family:宋ti;">ji单点式和可cheng式)</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;wendu、湿du试验箱有heng定试验箱、交变试验箱liang种情况。普通的高低wen试验箱一般指的是heng定高低wen试验箱,qi控制fang式为:she定一个目标wendu,试验箱具有自动hengwen到目标wendu点的能li。heng定wen湿du试验箱的控制控制fang式ye类似,she定一个目标wendu、湿du点,试验箱具有自动hengwen到目标wendu、湿du点的能li。高、低wen交变试验箱具有she定一条或zhe多条高低wen变化、循环的cheng序,试验箱有能li根据预置的曲线完成试验过cheng,并且可yi在*大升wen、降wen速率能li的范围na,**控制升wen、降wen的速率,ji可yi根据she定的曲线的xie率控制升wen、降wen速率。同样,高低wen交变湿热试验箱ye具觴ingぶ脀endu、湿du曲线,并且根据预置jin行控制的能li。<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;san、变wen速聅hi难e<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;普通的高低wen试验箱没有降wen速du的指标,cong环jingwendu降wen到标称的*低wendu的shi间一般为<span style="font-family:'Times New Roman';">90</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">120min</span><span style="font-family:宋ti;">。高低wen交变试验箱、高低wen交变湿热试验箱都觴ie鋡en速du的yao求,qi变wen速率一般yao求</span><span style="font-family:'Times New Roman';">1</span><span style="font-family:宋ti;">℃</span><span style="font-family:'Times New Roman';">/min</span><span style="font-family:宋ti;">,在ci速聅hi姆段a速du可调。而快速wendu变化试验箱的变wen速率较快,升wen、降wen速率可yi达到</span><span style="font-family:'Times New Roman';">3</span><span style="font-family:宋ti;">℃</span><span style="font-family:'Times New Roman';">/min</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">15</span><span style="font-family:宋ti;">℃</span><span style="font-family:'Times New Roman';">/min</span><span style="font-family:宋ti;">,在某些wendu段升wen、降wen速率甚至可yi达到</span><span style="font-family:'Times New Roman';">30</span><span style="font-family:宋ti;">℃</span><span style="font-family:'Times New Roman';">/min</span><span style="font-family:宋ti;">yi上。ge种规格、速du的快速wendu变化试验箱的wendu范围一般都是相同的,ji-</span><span style="font-family:'Times New Roman';">60</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">130</span><span style="font-family:宋ti;">℃,但考he降wen速du的变wen范围却bu尽相同,根据试验bu同的试验yao求,快速wendu变化试验箱变wen范围有的是-</span><span style="font-family:'Times New Roman';">55</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">80</span><span style="font-family:宋ti;">℃,而有的是-</span><span style="font-family:'Times New Roman';">40</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">80</span><span style="font-family:宋ti;">℃。关于快速wendu变化试验箱的变wen速率有liang种提法,深圳chuang杰仪qi仪表专业维修ge种环jing试验she备,一种是全cheng平jun升降wen速du,一种是线形升降wen速du(shi际上是每</span><span style="font-family:'Times New Roman';">5min</span><span style="font-family:宋ti;">平jun速du)。全cheng平jun速du是指在试验箱的变wen范围na,*高wendu与*低wendu之差值与shi间之比。目前国外ge环jing试验she备生产厂家提供的变wen速聅hi募际鮟an数都是指的全cheng平jun速率。线形升降wen速du指在ren意的每</span><span style="font-family:'Times New Roman';">5min</span><span style="font-family:宋ti;">shi间段na,能够bao证的变wen速率。而shi际上对于快速wendu变化试验箱纁i担琤ao证线形升降wen速du的难du*大、*关键的一段是,在降wen段*后的一个</span><span style="font-family:'Times New Roman';">5min</span><span style="font-family:宋ti;">的shi间段na,试验箱可yi达到的降wen速率。cong腸hizhi莇ujiang,线形升降wen速du(每</span><span style="font-family:'Times New Roman';">5min</span><span style="font-family:宋ti;">平jun速du)更科学。因ci试验she备*好具有全cheng平jun升降wen速du和线形升降wen速du(每</span><span style="font-family:'Times New Roman';">5min</span><span style="font-family:宋ti;">平jun速du)这liang个can数。一般纁i担咝紊祑en速du(每</span><span style="font-family:'Times New Roman';">5&nbsp;min</span><span style="font-family:宋ti;">平jun速du)是全cheng平jun升降wen速du的</span><span style="font-family:'Times New Roman';">1/2</span><span style="font-family:宋ti;">。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> 四、湿du范围的选ze<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;国na外环jing试验箱给出的湿du指标大都是<span style="font-family:'Times New Roman';">20</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">98</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">或</span><span style="font-family:'Times New Roman';">30</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">98</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">,如果湿热试验箱没有除湿系统,则湿du范围为</span><span style="font-family:'Times New Roman';">60</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">98</span><span style="font-family:宋ti;">%,这一类试验箱只能做高湿试验,但它的jia格低得多。值祄i⒁獾氖窃谑猟u指标后面yinggai注ming相ying的wendu范围,或给出*低露点wendu。因为相对湿du是与wendu直接相关的,对于同样的优liang含湿量,wendu越高,相对湿dujiu越小,如优liang含湿量为</span><span style="font-family:'Times New Roman';">5g/Kg</span><span style="font-family:宋ti;">(指</span><span style="font-family:'Times New Roman';">1</span><span style="font-family:宋ti;">公斤干空气中含有</span><span style="font-family:'Times New Roman';">5</span><span style="font-family:宋ti;">克的shui蒸汽),当wen秗en?lt;/span><span style="font-family:'Times New Roman';">29</span><span style="font-family:宋ti;">℃蔮ao喽允ren?lt;/span><span style="font-family:'Times New Roman';">20</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">,wen秗en?lt;/span><span style="font-family:'Times New Roman';">6</span><span style="font-family:宋ti;">℃蔮ao喽允ren?lt;/span><span style="font-family:'Times New Roman';">90</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">,当wendu降至</span><span style="font-family:'Times New Roman';">4</span><span style="font-family:宋ti;">℃yixia,相对湿du超过</span><span style="font-family:'Times New Roman';">100</span><span style="font-family:宋ti;">%,在箱tina会出蟴hi崧断窒蟆hi现高wen、高湿只xuyao往箱ti空气中喷shui蒸汽或雾化的shui珠,jin行加湿。低wen低湿则相对难于控制,因为cishi的优liang含湿量很低,有shi比大气中的优liang含湿量低很多,xuyao对箱tina流动的空气除湿,使空气变得干燥。目前国na外jue大多数的wen湿du箱都采用制冷除湿的原li,是在箱ti的空气预调室na加一zu制冷光管。当湿空气jing过冷管蔮ao琿i相对湿du会达到</span><span style="font-family:'Times New Roman';">100</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">,因空气饱和在光管上结露,使空气变得更干燥。这种除湿fang式li论上可达到lingduyixia的露点wendu,但是当冷点表面wendu到达</span><span style="font-family:'Times New Roman';">0</span><span style="font-family:宋ti;">℃蔮ao夤鼙砻娼崧兜膕hui滴会结bing,深圳chuang杰仪qi仪表专业维修wen湿du试验箱,cong而影响光管表面的热交换,使除湿能lixia降。又因为箱tibu可能优liangmifeng,大气中的湿空气会渗入到箱tina,使露点wendu回升。另一fang面,在光管间流动的湿空气只是在和光管(冷点)接触的瞬间达到饱和状tai而xi出shui蒸汽,因ci这种除湿fang法很难使箱tina的露点wendu在到</span><span style="font-family:'Times New Roman';">0</span><span style="font-family:宋ti;">℃yixia。shi际所达到的*低露点wen秗en?lt;/span><span style="font-family:'Times New Roman';">5</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">7</span><span style="font-family:宋ti;">℃。露点wendu</span><span style="font-family:'Times New Roman';">5</span><span style="font-family:宋ti;">℃相当于优liang含湿量为</span><span style="font-family:'Times New Roman';">0.0055g/Kg</span><span style="font-family:宋ti;">,对ying相对湿du</span><span style="font-family:'Times New Roman';">20</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">的wen秗en?lt;/span><span style="font-family:'Times New Roman';">30</span><span style="font-family:宋ti;">℃。如果yao求wendu</span><span style="font-family:'Times New Roman';">20</span><span style="font-family:宋ti;">℃jin相对湿du达到</span><span style="font-family:'Times New Roman';">20</span><span style="font-family:宋ti;">%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">,cishi的露点wen秗en?lt;/span><span style="font-family:'Times New Roman';">3</span><span style="font-family:宋ti;">℃,采用致冷fang式除湿是很困难的,所yi在做低wen低湿环jing测试shi选用空气干燥系统。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> wu、气候箱工作腔na环jing<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;can数〔如wendu、湿du、盐雾砽iang德shi取车木玠u指标都是在空载状taixia检测的结果,一旦置入被试验jian后,对试验箱工作腔na环jingcan数的jun匀xing将产生影响,试验jian占有的空间越大,这种影响yejiu越严重。shi测试验数据表ming,流场中yingfeng面与背feng面的wen差可达到<span style="font-family:'Times New Roman';">3</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">8</span><span style="font-family:宋ti;">℃,严重shi可大到</span><span style="font-family:'Times New Roman';">10</span><span style="font-family:宋ti;">℃yi上。因ci,必须尽量满足</span><span style="font-family:'Times New Roman';">a</span><span style="font-family:宋ti;">〕、</span><span style="font-family:'Times New Roman';">b</span><span style="font-family:宋ti;">〕liangxiangyao求,yibao证被试周围环jingcan数的jun匀xing。根据热传导的原li,箱壁附近气流的wendu通常与流场中心wendu相差</span><span style="font-family:'Times New Roman';">2</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">3</span><span style="font-family:宋ti;">℃,在高低wen的上xia限蔮ao箍赡艽锏?lt;/span><span style="font-family:'Times New Roman';">5</span><span style="font-family:宋ti;">℃。箱壁的wendu与箱壁附近流场的wendu又相差</span><span style="font-family:'Times New Roman';">2</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">3</span><span style="font-family:宋ti;">℃(视箱壁的结构和材liao而定)试验wendu与外界大气环jing相差越大,上述wen差ye越大,因ci,距箱壁(</span><span style="font-family:'Times New Roman';">100</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">150mm</span><span style="font-family:宋ti;">)距离na的空间是bu可利用空间。wendu范围的选ze目前,国外wendu试验箱的范围大ti上为-</span><span style="font-family:'Times New Roman';">73</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">177</span><span style="font-family:宋ti;">℃,或-</span><span style="font-family:'Times New Roman';">70</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">180</span><span style="font-family:宋ti;">℃。国na多数厂家一般为-</span><span style="font-family:'Times New Roman';">80</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">130</span><span style="font-family:宋ti;">℃,-</span><span style="font-family:'Times New Roman';">60</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">130</span><span style="font-family:宋ti;">℃,-</span><span style="font-family:'Times New Roman';">40</span><span style="font-family:宋ti;">~+</span><span style="font-family:'Times New Roman';">130</span><span style="font-family:宋ti;">℃,ye有高wen到</span><span style="font-family:'Times New Roman';">150</span><span style="font-family:宋ti;">℃。这些wendu范围通常可yi满足国najue大多数军用、民用wendu试验的xuyao,除fei确有特shuxuyao,如安装位置靠近fa动机等热源的外,bu可盲目提高wendu上限。因为上限wendu越高,箱tina外的wen差越大,箱tinabu流场的jun匀xingye詊iang睢?衫玫墓ぷ魇襱i积yejiu越小。另一fang面,上限wendu值越高,对箱壁夹层謝ieen材liao(如玻li棉等)的耐热xingyao求越高。箱timifengxing的yao求ye越高,使箱ti的制作成本增紋in?lt;/span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> 六、wendu波动du<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;wendu波动是一个比较容易shi现的can数,所有环jing试验she备厂紋i亩嗍氖匝橄鋝hi約hi膚endu波动都可yi控制在±<span style="font-family:'Times New Roman';">0.3</span><span style="font-family:宋ti;">℃的范围yina。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;七、feng速<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;有关标准规定,jin行环jing试验shiwen湿箱na的feng速ying小于<span style="font-family:'Times New Roman';">1.7m/s</span><span style="font-family:宋ti;">,对于试验本身纁i担琭eng速越小越好,feng速过大会加速试验jian表面与箱tina流动气流的热交换,于试验的真shixingbu利。但为了bao证试验箱工作室na的jun匀xing,试验箱na具有循环feng是必xu的。但是快速wendu变化试验箱yi及wendu、湿du、振动等多因素综合环jing试验箱,为譮ei蟊鋡en速率,必须加快箱tina循环气流的流速,feng速通常在</span><span style="font-family:'Times New Roman';">2</span><span style="font-family:宋ti;">~</span><span style="font-family:'Times New Roman';">3m/s</span><span style="font-family:宋ti;">。因ci,对于bu同的使用目的,feng速的限制是bu一样的。&nbsp;</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;八、wendujun匀du<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;为了更正确di模拟在自然界所遭shou的shi际环jing状况,在环jing试验謝ie匦隻ao证被试的周边处在同一wendu环jing条jianxia,为ci,必须对试验箱na的wendu梯du和wendu的波动du加yi限制。在国军标<span style="font-family:'Times New Roman';">GJB150.1</span><span style="font-family:宋ti;">-</span><span style="font-family:'Times New Roman';">86</span><span style="font-family:宋ti;">军用she备环jing试验fang法总则中ming确规定“试验样品附近测量系统的wenduying在试验wendu的±</span><span style="font-family:'Times New Roman';">2</span><span style="font-family:宋ti;">℃yina,qiwendu工bu超过</span><span style="font-family:'Times New Roman';">1</span><span style="font-family:宋ti;">℃</span><span style="font-family:'Times New Roman';">/m</span><span style="font-family:宋ti;">或总的*大值为</span><span style="font-family:'Times New Roman';">2.2</span><span style="font-family:宋ti;">℃(试验样品bu工作)</span><span style="font-family:'Times New Roman';">"</span><span style="font-family:宋ti;">。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;九、冷却fang式选ze<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;试验箱如果带有制冷系统,制冷系统xuyaojin行冷却。试验箱有feng冷、shui冷liang种形式。(1000L<span style="font-family:宋ti;">yixia箱ti一般采用feng冷式)</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;十、湿du的精du控制<o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;环jing试验箱中测量湿du多数是采用干湿球法,环jing试验she备的制造标准<span style="font-family:'Times New Roman';">GB10586</span><span style="font-family:宋ti;">yao求,相对湿du偏差ying在±2%</span><span style="font-family:'Times New Roman';">RH</span><span style="font-family:宋ti;">。为满足湿du控制精du的yao求,湿du试验箱的wendu控制精du较高,wendu波动一般小于±</span><span style="font-family:'Times New Roman';">0.2</span><span style="font-family:宋ti;">℃。否则很难达到湿du控制精du的yao求。</span><o:p></o:p> </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> &nbsp; </p> <p class="p0" style="margin-bottom:0pt;margin-top:0pt;"> <a href="http://www.weihuang18.net">买球app科技</a>(wewon)研fa,生产,xiao售,维修:<a 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wen湿du试验箱的选zefang法

    wen湿du试验箱又名hengwenheng湿试验箱,高低wen交变湿热试验箱。wen湿du试验箱是电子业、光电业、汽机车业、电子系统厂、电子ling配jian、汽车电讁in⑴缤恳怠⑸萍肌⒅埔┮怠⒐鷔i、军工、航空、新能源等产业领域必备的测试she备,用于测试和确定电工、电子及qi他及材liaojin行高wen、低wen、交变湿热du或heng定试验的wendu环jing变化后的can数及xing能.制造执行及符合标准GB/T5170.5-2008湿热试验she备fang法/GB/T10586-2006湿热试验箱技术条jian//GB/T2423.1-2008试验A低wen试验fang法/GB/T2423.2-2008试验B高wen试验fang法/GB/T2423.3-2006试验Caheng定湿热试验fang法。


    wen湿du试验箱是一款专业xing很强的试验测试仪qi,如he选ze一款合蕇hi慕枪愦笥没uyao考虑的问题。买球app试验she备小编今天在这儿给您小小的建议如xia几个fang面。

 

一、容积的选ze(生产测试用还是研fa测试用)

    将被试(元qijian、zujian、bujian或zheng机)置入wen湿du试验箱jin行试验蔮ao薭ao证被试周围气氛能满足试验规范所规定的环jing试验条jian,气候箱工作chicun与被试外廓chicun之间ying遵循yixia几点规定:

  1.被试的ti积(W×H×D)bu得超过试验箱有xiao工作空间的(7080)%(推荐选用75%)。对于在试验中fa热的推荐选用bu大于60%。

  2.被试的yingfeng断面积与gai断面上试验箱工作室总面积之比bu大于(3550)%(推荐选用35%)。

  3.被试外廓表面距试验箱壁的距离至少baochi100150mm,(推荐选用150mm)。

上述san点规定shi际上是相huyi存和统一的。yi1立fangmi正fangti箱子为li,测试占箱ti容积3/4面积。作出这种规定的li由是因为被试验jian置入箱ti后挤占了流chang的通dao,通dao变窄将导致气流流速的增紋in<铀倨饔氡皇匝閖ian之间的热交换。这与环jing条jian的再现bu符,因为在有关标准中对涉及wendu环jing试验都规定试验箱na试验样jian周围的空气流速buying超过1.7m/s,yi防止试验样jian和周围气氛产生bu符合shi約hi娜却肌T诳赵豷hi试验箱na平junfeng速为0.60.8m/s,bu超过1m/s,满足a)、b)liang点yao求所规定的空间及面积比蔮ao鞒〉膄eng速可能增大(50100)%,平jun*高feng速为(11.7m/s。满足标准规定的yao求。如果在试验中bu加限制di加大试验jian的ti积或yingfeng断面积,则shi际试验shi气流feng速将增大到超出试验标准所规定的*高feng速,qi试验结果的有xiaoxing将shou到怀yi。

 

 二、控制fang式的选ze:(heng定wen湿du和wen湿du交变-ji单点式和可cheng式)

   wendu、湿du试验箱有heng定试验箱、交变试验箱liang种情况。普通的高低wen试验箱一般指的是heng定高低wen试验箱,qi控制fang式为:she定一个目标wendu,试验箱具有自动hengwen到目标wendu点的能li。heng定wen湿du试验箱的控制控制fang式ye类似,she定一个目标wendu、湿du点,试验箱具有自动hengwen到目标wendu、湿du点的能li。高、低wen交变试验箱具有she定一条或zhe多条高低wen变化、循环的cheng序,试验箱有能li根据预置的曲线完成试验过cheng,并且可yi在*大升wen、降wen速率能li的范围na,**控制升wen、降wen的速率,ji可yi根据she定的曲线的xie率控制升wen、降wen速率。同样,高低wen交变湿热试验箱ye具觴ingぶ脀endu、湿du曲线,并且根据预置jin行控制的能li。

 

 san、变wen速聅hi难e

   普通的高低wen试验箱没有降wen速du的指标,cong环jingwendu降wen到标称的*低wendu的shi间一般为90120min。高低wen交变试验箱、高低wen交变湿热试验箱都觴ie鋡en速du的yao求,qi变wen速率一般yao求1/min,在ci速聅hi姆段a速du可调。而快速wendu变化试验箱的变wen速率较快,升wen、降wen速率可yi达到3/min15/min,在某些wendu段升wen、降wen速率甚至可yi达到30/minyi上。ge种规格、速du的快速wendu变化试验箱的wendu范围一般都是相同的,ji-60~+130℃,但考he降wen速du的变wen范围却bu尽相同,根据试验bu同的试验yao求,快速wendu变化试验箱变wen范围有的是-55~+80℃,而有的是-40~+80℃。关于快速wendu变化试验箱的变wen速率有liang种提法,深圳chuang杰仪qi仪表专业维修ge种环jing试验she备,一种是全cheng平jun升降wen速du,一种是线形升降wen速du(shi际上是每5min平jun速du)。全cheng平jun速du是指在试验箱的变wen范围na,*高wendu与*低wendu之差值与shi间之比。目前国外ge环jing试验she备生产厂家提供的变wen速聅hi募际鮟an数都是指的全cheng平jun速率。线形升降wen速du指在ren意的每5minshi间段na,能够bao证的变wen速率。而shi际上对于快速wendu变化试验箱纁i担琤ao证线形升降wen速du的难du*大、*关键的一段是,在降wen段*后的一个5min的shi间段na,试验箱可yi达到的降wen速率。cong腸hizhi莇ujiang,线形升降wen速du(每5min平jun速du)更科学。因ci试验she备*好具有全cheng平jun升降wen速du和线形升降wen速du(每5min平jun速du)这liang个can数。一般纁i担咝紊祑en速du(每5 min平jun速du)是全cheng平jun升降wen速du的1/2

 

四、湿du范围的选ze

 

    国na外环jing试验箱给出的湿du指标大都是2098RH3098RH,如果湿热试验箱没有除湿系统,则湿du范围为6098%,这一类试验箱只能做高湿试验,但它的jia格低得多。值祄i⒁獾氖窃谑猟u指标后面yinggai注ming相ying的wendu范围,或给出*低露点wendu。因为相对湿du是与wendu直接相关的,对于同样的优liang含湿量,wendu越高,相对湿dujiu越小,如优liang含湿量为5g/Kg(指1公斤干空气中含有5克的shui蒸汽),当wen秗en?/span>29℃蔮ao喽允ren?/span>20RH,wen秗en?/span>6℃蔮ao喽允ren?/span>90RH,当wendu降至4℃yixia,相对湿du超过100%,在箱tina会出蟴hi崧断窒蟆hi现高wen、高湿只xuyao往箱ti空气中喷shui蒸汽或雾化的shui珠,jin行加湿。低wen低湿则相对难于控制,因为cishi的优liang含湿量很低,有shi比大气中的优liang含湿量低很多,xuyao对箱tina流动的空气除湿,使空气变得干燥。目前国na外jue大多数的wen湿du箱都采用制冷除湿的原li,是在箱ti的空气预调室na加一zu制冷光管。当湿空气jing过冷管蔮ao琿i相对湿du会达到100RH,因空气饱和在光管上结露,使空气变得更干燥。这种除湿fang式li论上可达到lingduyixia的露点wendu,但是当冷点表面wendu到达0℃蔮ao夤鼙砻娼崧兜膕hui滴会结bing,深圳chuang杰仪qi仪表专业维修wen湿du试验箱,cong而影响光管表面的热交换,使除湿能lixia降。又因为箱tibu可能优liangmifeng,大气中的湿空气会渗入到箱tina,使露点wendu回升。另一fang面,在光管间流动的湿空气只是在和光管(冷点)接触的瞬间达到饱和状tai而xi出shui蒸汽,因ci这种除湿fang法很难使箱tina的露点wendu在到0℃yixia。shi际所达到的*低露点wen秗en?/span>57℃。露点wendu5℃相当于优liang含湿量为0.0055g/Kg,对ying相对湿du20RH的wen秗en?/span>30℃。如果yao求wendu20℃jin相对湿du达到20RH,cishi的露点wen秗en?/span>3℃,采用致冷fang式除湿是很困难的,所yi在做低wen低湿环jing测试shi选用空气干燥系统。

 

wu、气候箱工作腔na环jing

    can数〔如wendu、湿du、盐雾砽iang德shi取车木玠u指标都是在空载状taixia检测的结果,一旦置入被试验jian后,对试验箱工作腔na环jingcan数的jun匀xing将产生影响,试验jian占有的空间越大,这种影响yejiu越严重。shi测试验数据表ming,流场中yingfeng面与背feng面的wen差可达到38℃,严重shi可大到10℃yi上。因ci,必须尽量满足a〕、b〕liangxiangyao求,yibao证被试周围环jingcan数的jun匀xing。根据热传导的原li,箱壁附近气流的wendu通常与流场中心wendu相差23℃,在高低wen的上xia限蔮ao箍赡艽锏键/span>5℃。箱壁的wendu与箱壁附近流场的wendu又相差23℃(视箱壁的结构和材liao而定)试验wendu与外界大气环jing相差越大,上述wen差ye越大,因ci,距箱壁(100150mm)距离na的空间是bu可利用空间。wendu范围的选ze目前,国外wendu试验箱的范围大ti上为-73~+177℃,或-70~+180℃。国na多数厂家一般为-80~+130℃,-60~+130℃,-40~+130℃,ye有高wen到150℃。这些wendu范围通常可yi满足国najue大多数军用、民用wendu试验的xuyao,除fei确有特shuxuyao,如安装位置靠近fa动机等热源的外,bu可盲目提高wendu上限。因为上限wendu越高,箱tina外的wen差越大,箱tinabu流场的jun匀xingye詊iang睢?衫玫墓ぷ魇襱i积yejiu越小。另一fang面,上限wendu值越高,对箱壁夹层謝ieen材liao(如玻li棉等)的耐热xingyao求越高。箱timifengxing的yao求ye越高,使箱ti的制作成本增紋inⅫ/span>

 

六、wendu波动du

    wendu波动是一个比较容易shi现的can数,所有环jing试验she备厂紋i亩嗍氖匝橄鋝hi約hi膚endu波动都可yi控制在±0.3℃的范围yina。

 

 七、feng速

     有关标准规定,jin行环jing试验shiwen湿箱na的feng速ying小于1.7m/s,对于试验本身纁i担琭eng速越小越好,feng速过大会加速试验jian表面与箱tina流动气流的热交换,于试验的真shixingbu利。但为了bao证试验箱工作室na的jun匀xing,试验箱na具有循环feng是必xu的。但是快速wendu变化试验箱yi及wendu、湿du、振动等多因素综合环jing试验箱,为譮ei蟊鋡en速率,必须加快箱tina循环气流的流速,feng速通常在23m/s。因ci,对于bu同的使用目的,feng速的限制是bu一样的。 

 

 八、wendujun匀du

     为了更正确di模拟在自然界所遭shou的shi际环jing状况,在环jing试验謝ie匦隻ao证被试的周边处在同一wendu环jing条jianxia,为ci,必须对试验箱na的wendu梯du和wendu的波动du加yi限制。在国军标GJB150.186军用she备环jing试验fang法总则中ming确规定“试验样品附近测量系统的wenduying在试验wendu的±2℃yina,qiwendu工bu超过1/m或总的*大值为2.2℃(试验样品bu工作)"

 

 九、冷却fang式选ze

     试验箱如果带有制冷系统,制冷系统xuyaojin行冷却。试验箱有feng冷、shui冷liang种形式。(1000Lyixia箱ti一般采用feng冷式)

 

 十、湿du的精du控制

     环jing试验箱中测量湿du多数是采用干湿球法,环jing试验she备的制造标准GB10586yao求,相对湿du偏差ying在±2%RH。为满足湿du控制精du的yao求,湿du试验箱的wendu控制精du较高,wendu波动一般小于±0.2℃。否则很难达到湿du控制精du的yao求。

 

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