Thursday, July 12, 2012

The evolution of Mobile Pumping System(MPS). 超強採水系統的演進

The evolution of Mobile Pumping System(MPS). 超強採水系統的演進

First generation-2008 
It composed of a large volume bag, a mechanical three way valve and a Seabird pump. Ryan, although was just an undergraduate student helper, put this all together. At that time, we did not realize that the ~300 m long 1/4'' O.D. stainless steel fluid delivery line could generate such a large resistance to prevent over-pressured basement fluid from coming up to the seafloor at a higher flow rate. A pelagic pump was used on our third trial and we were able to collect about 4 L of good pristine basement fluids. The idea of integrating a powerful, clean pump to our pumping system was formed.  
第一代超強採水系統。它包含大體積採樣袋、手動三向閥和小抽水馬達,這些都是由實驗室的大學部助理萊恩所組合起來。此系統是本實驗室第一次用來抽取底夜樣品,由於經驗不足,並不了解內徑僅0.3公分的三百公尺底夜輸送管會造成很大的反壓,因而導致所選用的小馬達只協助採了四公升的樣品。





Second generation-2009 
A powerful clean "mega pump" made of Teflon and titanium has been integrated into the water sampling system. A "controller" was also build and integrated into this system for us to change the pump rate and to monitor the fluid temperature and chemistry while pumping. I remember sitting in the Alvin sphere using a laptop to control this sampling system. It was so amazing to control something just outside the Alvin window on the seafloor at about 2600m deep. However, without knowing the flow rate, it is hard to visualize the amount of fluid being pumped through our large volume bag. While the pumping system worked great, the connector between our pump to the CORK observatory gave Alvin pilots lots of trouble. It must be aligned very well and there was no visual indication of a good connection or not. Modification of the connector was a must to improve our success in collecting basement fluids.
第二代超強採水系統。為了加強抽水的力量,此次升級使用超強抽水馬達。接觸樣水部分的馬達頭全用鐵佛龍或鈦金屬等極乾淨材質,用以確保樣品不受污染。除此之外,我們還有一個中央控制器,透過電腦可協助我們控制馬達轉速和監測樣水溫度。第一次在水深2600米的艾爾文潛水艇內控制我們的採水系統感覺很酷,加上溫度探針可協助判斷是否有抽到底液,感覺離有大量樣水可做研究的日子越來越近了。但是不久又發現另一堆問題,如:無法判斷採水袋何時裝滿水!也不知道水的流量有多快!和連接cork的接頭失敗率太高!因此,航次結束後又得傷腦筋了!





Third generation-2010 
A flow sensor was added the third generation pumping system. We had also made and modified the connector, called Aeroquip. This year, we used remotely-operated-vessel JASON instead of manned-submersible Alvin. By having Dr. Cowen in the JASON control lab to help visually confirm whether good connection has been made had significantly increased our chances of successful connection. I remember we collected one bag after another high integrity basement fluids. At this time, although a flow sensor was installed, it did not work at the seafloor. This flow sensor was not tested at such high water pressure (4000 psi).     
第三代超強採水系統。此次加了流速計,但...航次前來不及做壓力測試,加上設計不良,所以流速計於第一次潛航就受損了,故此航次期間也沒有流速可協助監測收集了多少樣品。還好除了流速計,實驗室此次還改良了連接cork的接頭,加上此次採用無載人潛水艇傑生(沒有八小時時間限制),於是大大提高了成功率至70%(前兩次航次大概只有15%)。總結,這航次還蠻成功的!第一次收集超過十升的底夜,加起來總共超過200公升,可以提供做更多化學、生物方面的研究。







Fourth generation-2011 to now
Not just one but two flow sensors were installed in this system. Both sensors were tested at high pressure and they both passed the test. The sensors were also calibrated to yield reliable flow rates. We really had high hope and when we saw the first flow rate measurements shown on the JASON control van video, we all screamed "they work!!!" This system had helped us to collect so many basement fluids and several in situ filters for use to study the particles (i.e. cells). Yap, lots of effort to come to this point. We have collected more than 300 L of high integrity basement fluids and filter more than 200 L of basement fluids in situ into filters at the Juan de Fuca Ridge flank. This April (2012) we have also used this system to collect more than 250 L of basement fluids at the North Pond. 
第四代超強採水系統。經過三年的經驗累積,試了又試,找遍各種廠牌,為了就是要乾淨材質且可靠的流速計,當第一次在電腦前讀到流速時,全體成員在傑生的控制室都興奮的歡呼起來。不僅如此,此次還結合美可能(McLane)的過濾系統。除採水外,同時還可以即時過濾樣品與收集顆粒(不必採完水再過濾),只要時間允許,我們想要收集多少就有多少。這是我們第一次有那麼豐盛的成果,樣水收到超過300公升,濾紙也過濾了200公升以上,總共抽出超過500公升的底液。哇!很驚人吧!但我們還不滿足,下一個目標是改用全電腦控制的採樣系統,目標是採水超過1000公升。由於採樣技術的純熟,現在可以好好一探底液生物圈的情況了!     











No comments:

Post a Comment