臧 英,何思禹,王在滿,劉順財(cái),王緒國(guó),文智強(qiáng)
氣力式包衣雜交稻單粒排種器研制
臧 英,何思禹,王在滿※,劉順財(cái),王緒國(guó),文智強(qiáng)
(1. 華南農(nóng)業(yè)大學(xué)南方農(nóng)業(yè)機(jī)械與裝備關(guān)鍵技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室,廣州 510642;2. 華南農(nóng)業(yè)大學(xué)工程學(xué)院,廣州 510642)
為滿足雜交稻單粒播種的作業(yè)需求,該研究結(jié)合包衣稻種設(shè)計(jì)了一種單粒氣力式排種器,分析了吸種姿態(tài)對(duì)吸種精度的影響,利用稻種導(dǎo)流原理,設(shè)計(jì)了一種導(dǎo)流式吸種盤,對(duì)稻種在該吸種盤導(dǎo)流作用下的運(yùn)動(dòng)過(guò)程進(jìn)行了分析,建立了吸附過(guò)程中稻種與吸種盤之間的運(yùn)動(dòng)模型。采用包衣稻種(雜交稻五優(yōu)1179)為試驗(yàn)材料,采用三因素三水平全因素試驗(yàn)方法,在不同吸種盤轉(zhuǎn)速、吸室負(fù)壓和吸種盤結(jié)構(gòu)情況進(jìn)行試驗(yàn)分析。試驗(yàn)結(jié)果表明:在轉(zhuǎn)速30 r/min、吸室負(fù)壓1 400 Pa時(shí),有導(dǎo)流槽和輔助吸種裝置的吸種盤吸種效果最佳,單粒吸種率最高為81.58%,漏吸率為2.89%。試驗(yàn)結(jié)果驗(yàn)證了該吸種盤可有效提高單粒吸種率,滿足雜交稻單粒播種的作業(yè)需求,為雜交稻單粒播種提供了一定理論基礎(chǔ)。
農(nóng)業(yè)機(jī)械;設(shè)計(jì);試驗(yàn);包衣稻種;氣力式;單粒播種;導(dǎo)流槽;雜交稻;吸種姿態(tài)
精量穴直播技術(shù)是按水稻品種的種植農(nóng)藝要求,精量定距成穴地將稻種均布于田間[1-2]。其直播稻的種類主要為常規(guī)稻和雜交稻。常規(guī)稻每穴播種量一般為5~10粒,而對(duì)于分蘗能力較強(qiáng)的雜交稻,直播時(shí)每穴播種量一般為2~4粒[3-4]。隨著雜交稻種品質(zhì)的提高,其用種量越來(lái)越低[5],因此,單粒播種技術(shù)尤為重要。
近年來(lái),水稻機(jī)械直播技術(shù)得到快速發(fā)展[6-7]。機(jī)械式排種器主要適合中等或大播量要求,難以滿足雜交稻精少播量播種的需要。氣力式播種裝置具有傷種率低、對(duì)種子形狀適應(yīng)性高等特點(diǎn),是現(xiàn)在實(shí)現(xiàn)精少量播種的主要方式[8]。Karayel等[9-12]為實(shí)現(xiàn)玉米、棉花、大豆等作物種子的單粒播種,利用種子的物理特性建立數(shù)學(xué)模型,采用高速攝影等儀器觀察記錄整個(gè)播種過(guò)程,確定了氣力式播種機(jī)的最佳負(fù)壓值。Singh等[13]以棉花種子為研究對(duì)象,研究了氣力式排種器吸種孔的結(jié)構(gòu),采用理論與試驗(yàn)相結(jié)合的方式分析了孔徑與倒角對(duì)吸種效果的影響,確定最佳角度為120°。Yazgi等[14]為實(shí)現(xiàn)棉花和玉米種子的單粒播種,針對(duì)垂直圓盤式精密排種器,開展吸種盤不同吸孔數(shù)目和播種作業(yè)速度對(duì)排種性能影響的研究,試驗(yàn)結(jié)果表明,作業(yè)速度為1和1.5 m/s時(shí),排種器對(duì)不同吸孔數(shù)目均有良好適應(yīng)性。張國(guó)忠等[15-17]為實(shí)現(xiàn)雜交稻的精量穴播要求,采用群布吸孔的吸種盤設(shè)計(jì),通過(guò)研究真空度、孔徑和清種對(duì)平均播種量的影響,得到3~4粒/穴的合格率為81.87%。翟建波等[18]為解決雜交稻直播時(shí)因芽種流動(dòng)性差和細(xì)長(zhǎng)型狀造成種箱中芽種架空或者堵塞的問(wèn)題,設(shè)計(jì)了一種氣力式雜交稻精量穴直播排種器,滿足雜交稻2~4粒/穴的播種要求。邢赫等[19]設(shè)計(jì)了一種水稻播量可調(diào)氣力式排種器,通過(guò)設(shè)置不同流道,采用全因素的試驗(yàn)方法,實(shí)現(xiàn)雜交稻的播量可調(diào),且當(dāng)吸孔組數(shù)為12、吸種負(fù)壓為1 600 Pa和吸種盤排轉(zhuǎn)速為20r/min時(shí),1孔播種達(dá)到最佳效果,1~2粒率為82.41%,對(duì)實(shí)現(xiàn)單粒播種有一定的參考價(jià)值。王寶龍等[20]為提高雜交稻氣力滾筒集排式精量排種器的排種精度,設(shè)計(jì)了一種楔形攪種裝置,在吸種負(fù)壓為1 600 Pa、滾筒轉(zhuǎn)速為10 r/min、清種距離為1.94 mm時(shí),1~3粒的吸種合格率為86.00%。上述研究在一定程度上實(shí)現(xiàn)了水稻的小播量播種要求,但未涉及單粒播種技術(shù)。
已有研究在一定程度上提高了播種精度,對(duì)實(shí)現(xiàn)單粒播種有一定指導(dǎo)意義,相較于多粒播種的吸種精度,單粒播種對(duì)吸種要求更高。本文從氣力式排種器的吸種過(guò)程出發(fā),以稻種的吸附姿態(tài)為研究基礎(chǔ),進(jìn)行吸種盤的結(jié)構(gòu)設(shè)計(jì),以雜交稻五優(yōu)1179為研究對(duì)象,采用三因素三水平的全因素試驗(yàn)方法,分析了吸種盤轉(zhuǎn)速、吸室負(fù)壓和吸種盤的結(jié)構(gòu)對(duì)排種器吸種性能的影響,并進(jìn)行了排種性能試驗(yàn),以期為實(shí)現(xiàn)雜交稻的單粒播種提供依據(jù)。
水稻單粒氣力式排種器整體結(jié)構(gòu)如圖1所示,主要包括種箱1,種箱連接件2,吸室殼體3,排種殼體4,法蘭5,排種軸6,種刷7,吸種盤8,導(dǎo)種管9和卸種裝置10。
排種器工作時(shí),稻種由種箱1經(jīng)種箱連接件2流入排種殼體4中的吸種室內(nèi),受吸室殼體3的負(fù)壓流道內(nèi)流場(chǎng)作用,在吸種室內(nèi)被吸附在吸種盤8的吸孔上,吸種盤通過(guò)螺栓固定在法蘭5上,法蘭與排種軸6通過(guò)鍵連接同步轉(zhuǎn)動(dòng),被吸附的稻種隨吸種盤轉(zhuǎn)動(dòng)到投種區(qū),在吸室殼體3的正壓流場(chǎng)作用下離開吸種盤8經(jīng)導(dǎo)種管9落在播種溝內(nèi),吸種盤8上的吸孔被種刷7清理干凈后繼續(xù)吸種過(guò)程。播種作業(yè)結(jié)束后,卸種裝置10將剩余稻種回收。
由于稻種的球形度低,與吸孔配合方式難以固定,采用氣力式排種器吸種時(shí),經(jīng)常出現(xiàn)重吸與漏吸現(xiàn)象,根據(jù)文獻(xiàn)[21]與前期高速攝影觀察可知,稻種的吸附姿態(tài)是影響稻種與吸孔精準(zhǔn)配合的主要因素。通過(guò)高速攝影機(jī)拍攝排種器工作過(guò)程發(fā)現(xiàn),單粒稻種的吸附姿態(tài)可大致分3種:1)種子中部被吸孔吸附,且長(zhǎng)軸方向與吸種盤轉(zhuǎn)動(dòng)切向方向一致;2)種子中部被吸孔吸附,且長(zhǎng)軸方向不與吸種盤轉(zhuǎn)動(dòng)切向方向重合;3)種子一端被吸孔吸附,如圖2所示。
稻種的吸附過(guò)程就是稻種由靜止加速到勻速轉(zhuǎn)動(dòng)的過(guò)程[22],在吸種盤完成吸種前,稻種與吸孔在吸種盤運(yùn)動(dòng)方向上存在相對(duì)速度,會(huì)產(chǎn)生相對(duì)位移,若稻種在被吸孔吸附前,脫離了吸附范圍,會(huì)造成漏吸,圖3為稻種相對(duì)于吸孔的運(yùn)動(dòng)示意圖。
當(dāng)?shù)痉N長(zhǎng)軸方向相對(duì)于吸種盤轉(zhuǎn)動(dòng)為切向姿態(tài)時(shí),吸種有效距離長(zhǎng),有利于被吸孔吸附。因此,通過(guò)對(duì)稻種吸附過(guò)程的稻種運(yùn)動(dòng)分析,可為實(shí)現(xiàn)對(duì)吸孔附近的稻種姿態(tài)調(diào)整、提高排種器的吸種性能、進(jìn)行吸種盤結(jié)構(gòu)設(shè)計(jì)提供理論基礎(chǔ)。
通過(guò)上述分析可知,稻種的吸附姿態(tài)將對(duì)稻種的吸附精度產(chǎn)生影響。吸種盤是排種器的核心部件,直接與稻種接觸,其結(jié)構(gòu)參數(shù)與尺寸參數(shù)將直接影響稻種的吸附姿態(tài),如圖4所示,吸種盤由吸孔、導(dǎo)流槽和輔助吸種裝置構(gòu)成。吸種盤直徑165 mm,厚度2 mm,盤面均布16個(gè)吸孔,吸孔孔徑為1.8 mm(根據(jù)經(jīng)驗(yàn)公式,=(0.64~0.66)[23]計(jì)算,為吸孔直徑,為稻種平均寬度,為2.85 mm)。吸種盤上設(shè)有16個(gè)導(dǎo)流槽,導(dǎo)流槽由內(nèi)側(cè)和外側(cè)導(dǎo)流槽構(gòu)成,分別位于吸孔兩側(cè),整個(gè)導(dǎo)流槽長(zhǎng)33 mm,寬16 mm。輔助吸種裝置緊靠吸孔外側(cè),為長(zhǎng)條狀,與外側(cè)導(dǎo)流槽平行,長(zhǎng)5 mm,寬2 mm,高2 mm。
當(dāng)吸種盤轉(zhuǎn)動(dòng)時(shí),吸種室內(nèi)的稻種在外側(cè)導(dǎo)流槽1和內(nèi)側(cè)導(dǎo)流槽2共同作用下,向吸孔3處匯聚。在這個(gè)過(guò)程中,由于稻種為紡錘狀,當(dāng)吸種盤轉(zhuǎn)動(dòng)時(shí),稻種受導(dǎo)流槽和種群的作用,為通過(guò)兩側(cè)導(dǎo)流槽形成的隘口,稻種將長(zhǎng)軸方向與吸種盤轉(zhuǎn)動(dòng)的切線方向重合。通過(guò)導(dǎo)流槽的稻種在吸孔3處受輔助吸種裝置4和吸孔處負(fù)壓的作用而不斷加速,最終被吸附在吸孔3上,完成吸種過(guò)程。
1.外側(cè)導(dǎo)流槽 2.內(nèi)側(cè)導(dǎo)流槽 3.吸孔 4.輔助吸種裝置
1.Outside guide groove 2.Inner guide groove 3.Suction hole 4.Auxiliary seed suction device
注:為吸種盤轉(zhuǎn)動(dòng)角速度,rad·s-1。
Note:is the rotation angular velocity of the seed sucking plate, rad·s-1.
圖4 吸種盤結(jié)構(gòu)示意圖
Fig.4 Structure diagram of seed sucking plate
2.2.1 導(dǎo)流槽深度
通過(guò)對(duì)稻種吸附姿態(tài)分析可知,稻種長(zhǎng)軸方向與吸種盤轉(zhuǎn)動(dòng)方向切向一致時(shí)有利于吸種。為實(shí)現(xiàn)稻種吸附姿態(tài)的調(diào)整,利用導(dǎo)流槽的凹槽結(jié)構(gòu)對(duì)一端靠近吸種盤的稻種進(jìn)行翻轉(zhuǎn)。如圖5所示,當(dāng)吸種盤轉(zhuǎn)動(dòng)時(shí),導(dǎo)流槽帶動(dòng)一端靠近吸種盤的稻種翻轉(zhuǎn),稻種由姿態(tài)1變?yōu)樽藨B(tài)2。為分析導(dǎo)流槽深度對(duì)稻種翻轉(zhuǎn)的影響,建立導(dǎo)流槽深度對(duì)稻種吸附姿態(tài)的影響模型。
根據(jù)稻種與吸種盤之間的受力分析,以稻種翻轉(zhuǎn)前的質(zhì)心位置為坐標(biāo)原點(diǎn)軸方向與吸種盤盤面垂直,軸方向與吸種盤轉(zhuǎn)動(dòng)的切向方向一致,建立稻種在軸方向的受力方程:
式中f2=μF,為吸種盤與稻種間的摩擦系數(shù),取0.36; F1=Ftan,為種子的自然休止角,通過(guò)試驗(yàn)求得=31.87°。
為使目標(biāo)稻種通過(guò)導(dǎo)流槽后,在種群作用力下實(shí)現(xiàn)姿態(tài)調(diào)整,對(duì)目標(biāo)稻種與底層稻種的接觸點(diǎn)′點(diǎn)的力矩進(jìn)行分析,目標(biāo)稻種在吸種盤作用下轉(zhuǎn)動(dòng)時(shí),應(yīng)滿足:
將式(1)代入式(2)求得≥50°,根據(jù)圖5中稻種轉(zhuǎn)動(dòng)力學(xué)模型可知:
根據(jù)前期不同稻種的三軸尺寸測(cè)量結(jié)果,稻種的長(zhǎng)軸尺寸一般在6~9 mm之間,為提高吸種盤的適應(yīng)性,取為9 mm,代入式(3)求得導(dǎo)流槽深度為1.5 mm。根據(jù)文獻(xiàn)[24],結(jié)合包衣稻種的物理特性,導(dǎo)流槽斜面傾角取45°。
2.2.2 內(nèi)側(cè)導(dǎo)流槽
為了驅(qū)使吸孔內(nèi)側(cè)的稻種向吸孔處靠近,并將吸孔處稻種姿態(tài)調(diào)整為長(zhǎng)軸方向與吸種盤運(yùn)動(dòng)的切向方向一致。根據(jù)文獻(xiàn)[25]設(shè)計(jì)內(nèi)側(cè)導(dǎo)流槽,使吸孔內(nèi)側(cè)的稻種沿導(dǎo)流槽向吸孔處運(yùn)動(dòng)。在吸種盤轉(zhuǎn)動(dòng)時(shí),稻種一邊隨吸種盤轉(zhuǎn)動(dòng),一邊沿著導(dǎo)流曲線從點(diǎn)運(yùn)動(dòng)至點(diǎn),在吸孔上方匯聚,在該曲線上,稻種運(yùn)動(dòng)的絕對(duì)軌跡為點(diǎn)所在基圓切線方向的線段,如圖6所示。
內(nèi)側(cè)導(dǎo)流槽曲線表達(dá)式為
式中x為稻種在軸坐標(biāo)值,mm;y為稻種在軸坐標(biāo)值,mm;0為導(dǎo)流槽曲線基圓半徑,mm;為稻種由點(diǎn)運(yùn)動(dòng)至點(diǎn)時(shí),吸種盤轉(zhuǎn)過(guò)的角度,(°);為稻種轉(zhuǎn)角速率系數(shù),取0.1~0.9。
根據(jù)圖6幾何關(guān)系有:
式中1=0/cos,化簡(jiǎn)式(5)得:
當(dāng)?shù)痉N隨導(dǎo)流槽向吸孔處運(yùn)動(dòng)時(shí),為使稻種長(zhǎng)軸方向與吸孔切向方向保持一致,的值應(yīng)大于45°。為保證導(dǎo)流槽離開堆積的稻種前,帶動(dòng)吸種室內(nèi)側(cè)稻種從點(diǎn)運(yùn)動(dòng)至吸孔上方點(diǎn),依據(jù)所使用的氣力式排種器排種殼體結(jié)構(gòu)[26],取0為45 mm,依據(jù)吸種室內(nèi)的種層高度,取為0°~50°。將上述參數(shù)代入式(6)中,求得轉(zhuǎn)角速率系數(shù)為0.1。
2.2.3 外側(cè)導(dǎo)流槽
為使吸孔外側(cè)的稻種向吸孔處靠近,對(duì)外側(cè)導(dǎo)流槽上的稻種受力進(jìn)行分析,如圖7所示。
根據(jù)稻種在外側(cè)導(dǎo)流槽上的受力分析可知,稻種在、方向上的受力方程為
解方程,化簡(jiǎn)后可得:
根據(jù)前期試驗(yàn)結(jié)果,稻種在不銹鋼板上的滑動(dòng)摩擦系數(shù)=0.36,吸孔所在圓的半徑=70 mm。根據(jù)田間作業(yè)效率要求,水田作業(yè)機(jī)具的行走速度一般在0.5~1 m/s,對(duì)應(yīng)排種器轉(zhuǎn)速在20~40 r/min之間[19]。故的取值范圍為2.09~4.19 rad/s,求得的范圍為31.15°~55.87°。取值越小,越有利于提高稻種的流動(dòng),同時(shí)為了便于加工,設(shè)計(jì)為35°。
在吸種盤轉(zhuǎn)速高的情況下,僅靠負(fù)壓作用吸種精度難以保證。為此,本文設(shè)計(jì)了輔助吸種裝置帶動(dòng)吸孔處的稻種,以提高吸種精度[27-30]。
如圖8所示,通過(guò)前期試驗(yàn)研究,輔助吸種裝置設(shè)計(jì)為長(zhǎng)條狀,長(zhǎng)5 mm,寬2 mm,高2 mm,粘附在吸孔外側(cè),長(zhǎng)軸方向與吸孔相切,且與外側(cè)導(dǎo)流槽平行。
為研究輔助吸種裝置對(duì)吸孔處稻種的帶動(dòng)作用,對(duì)吸孔處的稻種進(jìn)行受力分析(由于吸種盤上的導(dǎo)流槽對(duì)稻種的姿態(tài)進(jìn)行調(diào)整,故以長(zhǎng)軸方向與吸種盤轉(zhuǎn)動(dòng)方向的切向一致的稻種為研究目標(biāo))。稻種的加速度=2/,式中為稻種隨盤轉(zhuǎn)動(dòng)的線速度,為稻種的長(zhǎng)軸長(zhǎng)度,吸孔處稻種的受力如圖9所示。
參考袁月明[31]對(duì)稻種充種區(qū)的受力分析,稻種在吸力作用下緊貼吸種盤,受吸種盤的摩擦力和輔助吸種裝置的摩擦力作用加速運(yùn)動(dòng),目標(biāo)稻種由靜止?fàn)顟B(tài)加速至隨盤轉(zhuǎn)動(dòng)。由圖9可知,吸孔處稻種在軸上的受力關(guān)系為
式中f2=Fμ,為吸種盤與稻種間的摩擦系數(shù)。
吸力與真空度之間的關(guān)系為
式中為吸孔面積,m2,πd/4,為吸孔直徑,mm;H為吸室臨界真空度,Pa。
聯(lián)立式(9)~(10)有:
由式(11)可知,在吸種盤轉(zhuǎn)速一定的情況下,輔助吸種裝置提供的作用力f1能減少稻種吸附所需負(fù)壓值,有利于降低吸種盤轉(zhuǎn)速和吸室負(fù)壓對(duì)吸種精度的影響,提高吸種性能。
根據(jù)上述理論分析進(jìn)行吸種盤結(jié)構(gòu)設(shè)計(jì),為了驗(yàn)證所設(shè)計(jì)吸種盤的單粒吸種性能,對(duì)該排種器進(jìn)行了臺(tái)架試驗(yàn)。
由于水稻裸種存在形狀不規(guī)則、流動(dòng)性差和脆性大等特性[32],影響吸種精度,故試驗(yàn)選用華南農(nóng)業(yè)大學(xué)培育、廣東農(nóng)科院包衣處理的五優(yōu)1179。分別測(cè)量未包衣和包衣處理后的稻種物理參數(shù)(尺寸、千粒質(zhì)量、休止角),其含水率分別為13.8%、18.0%,物理特性如表1所示。
表1 稻種物理參數(shù)
由表1可知,包衣處理后的稻種三軸尺寸更大,氣流作用有效面大,休止角小,稻種流動(dòng)性好,相較于裸種更易于吸附。
試驗(yàn)裝置如圖10所示,主要包括排種器、驅(qū)動(dòng)電機(jī)、風(fēng)機(jī)、電子氣壓計(jì)和高速攝影機(jī)。試驗(yàn)采用微差壓變電子氣壓計(jì)進(jìn)行氣壓監(jiān)測(cè),采用美國(guó)PHOTRON公司生產(chǎn)的FASTCAMSUPER 10K型高速攝像機(jī)對(duì)排種器的吸種情況進(jìn)行連續(xù)拍攝記錄。
吸種盤轉(zhuǎn)速是影響播種精度的因素之一[33]。根據(jù)田間作業(yè)速度要求,氣力式排種器吸種盤的轉(zhuǎn)速一般為20~40 r/min。為提高排種器適應(yīng)性,研究高速作業(yè)狀態(tài)下不同吸種盤的吸種情況,排種器轉(zhuǎn)速設(shè)置為30、40和50 r/min。
參考現(xiàn)有垂直圓盤式排種器的研究,吸附1~3粒稻種的最佳工作負(fù)壓為1 600 Pa[34],由于本文所設(shè)計(jì)的排種器只吸附1粒稻種,負(fù)壓要比多粒吸附的負(fù)壓值小。根據(jù)預(yù)試驗(yàn)(如表2所示),當(dāng)負(fù)壓值過(guò)大時(shí),吸種合格率下降,重吸率增大,因此負(fù)壓真空度取1 200~1 600 Pa。
表2 吸種盤轉(zhuǎn)速30 r·min-1時(shí)的吸種效果
為明確吸種盤結(jié)構(gòu)對(duì)排種器吸種性能的影響,選取3種吸種盤結(jié)構(gòu)進(jìn)行試驗(yàn),分別為僅有導(dǎo)流槽的吸種盤(a盤)、僅有輔助吸種裝置的吸種盤(b盤)和導(dǎo)流槽加輔助吸種裝置的吸種盤(c盤),如圖11所示。結(jié)合吸種盤轉(zhuǎn)速、吸室負(fù)壓進(jìn)行單粒排種全因素試驗(yàn)。
試驗(yàn)因素水平如表3所示。
表3 試驗(yàn)因素與水平
根據(jù)GB/T6973-2005《單粒(精密)播種機(jī)試驗(yàn)方法》[35]進(jìn)行試驗(yàn)設(shè)計(jì),定義每組吸孔吸附1粒稻種為單粒指標(biāo),≥2粒為重吸,0粒為漏吸,每組試驗(yàn)統(tǒng)計(jì)250粒種子,重復(fù)3次。
其試驗(yàn)結(jié)果如表4所示。由表4可知,a盤的平均單粒率為63.16%,b盤的平均單粒率為74.81%,c盤的平均單粒率為78.63%。c盤的吸種單粒率最高,其原因在于,b盤和c盤利用輔助吸種裝置對(duì)稻種吸附位置進(jìn)行限制,提高了吸種單粒率,a盤只有導(dǎo)流槽,吸種單粒率受轉(zhuǎn)速和負(fù)壓的影響較大。
表4 全因素試驗(yàn)統(tǒng)計(jì)結(jié)果
由表4的漏吸率可知,各吸種盤的漏吸情況均隨負(fù)壓的增大而減少,隨轉(zhuǎn)速的增大而增大,符合氣力式排種器的吸種特點(diǎn)。其中a盤受轉(zhuǎn)速和負(fù)壓的影響最大,在試驗(yàn)參數(shù)條件下,漏吸率為15.46%~46.87%;b盤的漏吸率為7.86%~22.85%;c盤的漏吸率為2.11%~12.71%。在相同條件下,c盤的漏吸率受轉(zhuǎn)速和負(fù)壓的影響最小,漏吸率最低,在轉(zhuǎn)速為30 r/min、負(fù)壓為1 600 Pa時(shí),最低漏吸率為2.11%。其原因在于,c盤通過(guò)導(dǎo)流槽實(shí)現(xiàn)稻種吸附姿態(tài)的調(diào)整,輔助吸種裝置帶動(dòng)吸孔處的稻種,降低了漏吸率。a盤沒有輔助吸種裝置,稻種的吸附僅靠負(fù)壓流場(chǎng)的作用來(lái)實(shí)現(xiàn),在負(fù)壓較低和吸種盤轉(zhuǎn)速過(guò)快時(shí),稻種很難被吸附;b盤由缺少導(dǎo)流槽對(duì)稻種吸附姿態(tài)的調(diào)整,漏吸率高。
對(duì)上述試驗(yàn)結(jié)果進(jìn)行方差分析,結(jié)果如表5所示,由方差結(jié)果可知,在高速作業(yè)速度范圍和所選負(fù)壓范圍內(nèi),吸種盤的結(jié)構(gòu)對(duì)漏吸率、重吸率和單粒率有極顯著的影響(<0.01),吸種盤轉(zhuǎn)速和吸室負(fù)壓對(duì)漏吸率以及重吸率的影響極為顯著(<0.01)。3個(gè)試驗(yàn)因素對(duì)單粒率的影響顯著性從大到小的順序?yàn)?、、,其中吸種盤的結(jié)構(gòu)對(duì)單粒率的影響極為顯著(<0.01),吸種盤轉(zhuǎn)速和吸室負(fù)壓對(duì)單粒率的影響不顯著(>0.05)。本文通過(guò)預(yù)試驗(yàn)與理論分析,已基本確定了適宜的工作負(fù)壓范圍,在進(jìn)行試驗(yàn)分析時(shí),負(fù)壓與轉(zhuǎn)速的水平范圍控制在適宜的范圍內(nèi)。
由圖12高速攝影照片可以看出,導(dǎo)流槽加輔助吸種裝置的吸種盤結(jié)構(gòu)能對(duì)吸孔處稻種吸附姿態(tài)調(diào)整,使得吸附稻種的長(zhǎng)軸方向均與吸種盤切向方向保持一致,實(shí)現(xiàn)對(duì)稻種吸附姿態(tài)的調(diào)整。
表5 方差分析
注:**表示極顯著(<0.01)。
Note: ** is extremely significant (<0.01).
本文以包衣雜交稻種為試驗(yàn)材料,進(jìn)行了單粒吸種試驗(yàn)。試驗(yàn)結(jié)果表明,本文所設(shè)計(jì)的吸種盤可有效的提高單粒吸種率。其原因?yàn)椋何N盤上的導(dǎo)流槽通過(guò)對(duì)吸孔處稻種的姿態(tài)進(jìn)行改變,提高了吸種率,所以帶導(dǎo)流槽加輔助吸種裝置的吸種盤其空穴率要低于只有輔助吸種裝置的吸種盤;輔助吸種裝置位于吸孔外側(cè),能對(duì)吸孔處的稻種進(jìn)行提速和對(duì)吸種位置進(jìn)行限制,提高了稻種的吸附精度,所以帶輔助吸種裝置的吸種盤其單粒率要高于僅有導(dǎo)流槽的吸種盤。
試驗(yàn)材料選用的雜交稻五優(yōu)1179的包衣稻種,相較于裸種,其三軸尺寸有所增大,流動(dòng)性更好,有利于提高吸種精度。本文僅對(duì)包衣稻種的吸種精度進(jìn)行研究,沒有分析排種器結(jié)構(gòu)對(duì)包衣破損率的影響,對(duì)于包衣材料和包衣厚度等對(duì)稻種破損率的影響還需進(jìn)一步研究。
本文對(duì)試驗(yàn)結(jié)果進(jìn)行方差分析發(fā)現(xiàn),吸種盤轉(zhuǎn)速和吸室負(fù)壓對(duì)漏吸率和重吸率的影響顯著,但對(duì)合格率的影響不顯著,這與現(xiàn)有研究有差異。其原因在于,本文試驗(yàn)所選取的負(fù)壓和轉(zhuǎn)速通過(guò)理論分析與預(yù)試驗(yàn)確定,在此范圍內(nèi),合格率受轉(zhuǎn)速和負(fù)壓的影響不顯著,但超過(guò)該范圍內(nèi),吸種負(fù)壓與轉(zhuǎn)速將對(duì)合格率產(chǎn)生一定影響[19]。
1)為滿足雜交稻的單粒播種要求,本文對(duì)氣力式排種器的吸種原理進(jìn)行研究,通過(guò)理論分析、高速攝影技術(shù)與試驗(yàn)臺(tái)試驗(yàn)相結(jié)合發(fā)現(xiàn),當(dāng)吸孔處的稻種其長(zhǎng)軸方向與吸孔切向方向一致時(shí),有利于提高排種器的吸種性能。因此,設(shè)計(jì)了一種導(dǎo)流槽加輔助吸種裝置的吸種盤結(jié)構(gòu),并通過(guò)理論分析,確定了吸種盤參數(shù)。
2)選取雜交稻五優(yōu)1179的包衣稻種為試驗(yàn)材料,在不同吸種負(fù)壓、吸種盤轉(zhuǎn)速和吸種盤結(jié)構(gòu)條件下進(jìn)行三因素三水平全因素試驗(yàn),試驗(yàn)結(jié)果表明:導(dǎo)流槽加輔助吸種裝置的吸種盤結(jié)構(gòu)單粒吸種率高,吸種精度受轉(zhuǎn)速和氣壓的影響小,在轉(zhuǎn)速30 r/min、吸室負(fù)壓1 400 Pa時(shí),單粒吸種率最高為81.58%,相較于另外2種吸種盤結(jié)構(gòu),漏吸率較低,為2.89%,滿足雜交稻單粒播種的技術(shù)要求。
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Design of pneumatic single seed metering device for coated hybrid rice
Zang Ying, He Siyu, Wang Zaiman※, Liu Shuncai, Wang Xuguo, Wen Zhiqiang
(1.,,510642,;2.,,510642,)
Direct seeding of rice is widely expected as one of the most important technology in mechanized rice planting. At present, two ways were mainly divided into the transplanting and direct seeding. The direct seeding can reduce the input of procedures and costs, while the growth cycle. In the complex field environment, direct-seeded rice seeds are easily affected by diseases, pests, weeds, and flooding, leading to greatly reduce the emergence rate and the yield. Alternatively, the seed coating technology can be used to provide micro-fertilizers, growth regulators and pesticides for the germination of seeds and the growth of seedlings. Specifically, the film-forming agents, adhesives, and other ingredients are generally used to uniformly bond the active ingredients on the surface of seeds. Since its convenient application, low cost, as well as resistance to pests and diseases, the seed coating technology can greatly contribute to enhance the seedling rate in the field, and the growth potential of seedlings. Particularly, small environmental pollution can meet the harsh requirement of ecological agriculture. In recent years, the mechanical direct seeding technology of rice has been commonly used in a large area in China, one of which the precision hole direct seeding technology of rice has good ventilation and permeability in the paddy field. The rice seeds are distributed evenly in the field, according to the agronomic requirements of rice varieties. The main types of direct seeding rice are the conventional rice and hybrid rice. The sowing rate is normally 5-10 per hole of conventional rice, while the sowing rate is generally 2-4 grains per hole for the hybrid rice with strong tillering ability. With the emergence of super hybrid rice and some high-quality rice varieties, the single-grain sowing has become particularly important, due to it meets the requirements of agronomic planting. In this study, a single-grain pneumatic seed metering device was designed for the coated rice to meet the demand of single-grain sowing of super rice. The physical parameters of coated rice seeds were measured. A movement model was established between rice seed and diversion suction plate during adsorption, according to the movement process of rice seed under the action of suction tray. The optimal negative pressure was calculated under the ideal condition of seed suction disk. Taking the coated rice variety (Super Rice Wuyou 1179) as the experimental object, the three-factor and three-level all-factor test was used to analyze the seed absorption of rice varieties at the speed of suction tray, negative pressure of suction chamber, and structure of seed suction tray. The experimental results show that the seed suction effect was the best, when the rotating speed of diversion suction tray was 30 r/min, and the negative pressure of suction chamber was 1 400 Pa. The seed sucking effect was best in the seed sucker structure with diversion groove and auxiliary seed sucking device, where the maximum of single seed sucking rate was 81.58%, and the leakage rate was 2.89%. Therefore, the suction tray can effectively improve the seed absorption rate per grain, suitable for the needs of single-grain sowing of super rice. The finding can provide a theoretical basis for the rapid development of single-grain sowing of rice.
agricultural machinery;design; test; coated rice seed; pneumatic; single seed seeding;diversion groove; hybrid rice; sucking posture
10.11975/j.issn.1002-6819.2021.01.002
S223.2
A
1002-6819(2021)-01-0010-09
臧英,何思禹,王在滿,等. 氣力式包衣雜交稻單粒排種器研制[J]. 農(nóng)業(yè)工程學(xué)報(bào),2021,37(1):10-18.doi:10.11975/j.issn.1002-6819.2021.01.002 http://www.tcsae.org
Zang Ying, He Siyu, Wang Zaiman, et al. Design of pneumatic single seed metering device for coated hybrid rice[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(1): 10-18. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2021.01.002 http://www.tcsae.org
2020-09-28
2020-12-20
國(guó)家重點(diǎn)研發(fā)計(jì)劃項(xiàng)目(2018YFD0100800);國(guó)家自然科學(xué)基金(31871529);現(xiàn)代農(nóng)業(yè)產(chǎn)業(yè)技術(shù)體系建設(shè)專項(xiàng)基金(CARS-01-41)
臧英,博士,教授,研究方向?yàn)樗旧a(chǎn)機(jī)械關(guān)鍵技術(shù)與裝備。
王在滿,博士,副研究員,研究方向?yàn)樗旧a(chǎn)機(jī)械化關(guān)鍵技術(shù)與裝備。
中國(guó)農(nóng)業(yè)工程學(xué)會(huì)高級(jí)會(huì)員:臧英(E041200443S)