斯派莎克蒸汽減壓閥|SpiraxSarco蒸汽減壓閥結構特點和用處： 

  DP27/17導閥型隔膜式減壓閥為鑄鋼材質閥體，主閥閥芯，隔膜，導閥，內部彈簧及濾網等均為不銹鋼材質。適用于蒸汽和壓縮空氣系統。壓力調節比可達10：1，控制準確。當壓力調節范圍超過10：1時，應采用兩個減壓閥串聯布置。斯派莎克蒸汽減壓閥|SpiraxSarco蒸汽減壓閥為軟閥座型號，用于壓縮空氣系統，或其它工業氣體（不適用于氧氣）。DP143H為用于高溫的型號。常用規格有DN15∽80，PN1.6/2.5MPa，使用工作溫度DP143≤300℃，DP143G≤120℃，DP143H≤350℃壓力調節范圍（錐形彈簧）0.02∽1.7MPa.由壓力反饋管把閥后壓力傳遞至膜盒，膜盒產生位移使閥芯與閥座流通截面積改變而維持閥后壓力穩定在一定范圍內。該系列調節閥可配用多種不同用途的先導閥，有壓力先導式，溫度先導式以及壓力溫度組合先導式。每一種先導閥均可通過先導閥適配器進行組合與拆卸。這種模塊設計使得系列產品用途十分廣泛。該系列減壓閥提供了覆蓋整個壓力范圍的彈簧等級，并用顏色加以區別。最常選用的先導閥有P型壓

  斯派莎克DP17，27系列減壓閥的設計制造完全依據使用者的需求，其多元化的組合在工業界沒有任何其他的減壓閥可與之媲美。為了實現多目標控制設備的獨立性和經濟性，可在同一個主閥上組合多種控制，無論是溫度控制、壓力調節還是二者在一起，都能做到反應迅速、控制精確、安全可靠。同時，25P系列減壓閥的所有零件均能夠分解檢查或保養，而無需移動管路中的主閥體。正確的選型和安裝保養，更能保證其長期無故障的工作。

 

 

斯派莎克蒸汽減壓閥|SpiraxSarco蒸汽減壓閥工作原理

        啟動前導閥彈簧處于自由狀態時，主閥和導閥處于關閉狀態。導閥有彈簧力作用打開，蒸汽經由導閥進入主隔膜室，一部分蒸汽則經由控制孔流出，當導閥流入的蒸汽大于由控制孔流出的蒸汽，主隔膜閥中的控制壓力增大，打開主閥。隨著蒸汽流過主閥，下游壓力的增量經由感應管反饋，作用在導閥隔膜下，平衡隔膜上部的彈簧壓力，使導閥組建關閉節流，維持主隔膜中的壓力，控制主閥開度輸送適量的蒸汽。調節導閥隔膜上的彈簧即可改變下游壓力。

斯派莎克蒸汽減壓閥|SpiraxSarco蒸汽減壓閥主要特征

導閥彈簧：三種顏色的彈簧，可提供從0.2-14bar g范圍內不同壓力的準確控制

溫度調節刻度盤：快速準確的設定所需溫度。

溫度感應器：在溫控元件中有無需補償的液體，感應瞬時溫度的變化，提供準確的控制。

百分之百的測試：每一個25P系列的減壓閥在出廠前都經蒸汽測試，以確保無故障的操作

Many reducing valve problems are caused by the presence of moisture or dirt. A steam separator and strainer with fine mesh screen， if fitted before the valve， will help to prevent such problems. The strainer is fitted on its side to prevent the body filling with water and to ensure that the full area of the screen is effective. Large isolation valves will also benefit from being installed on their side for the same reason.

All upstream and downstream pipework and fittings must be adequately sized to ensure that the only appreciable pressure drop occurs across the reducing valve itself. If the isolating valves are the same size as the reducing valve connections， they will incur a larger pressure drop than if they are sized to match the correctly sized， larger diameters of the upstream and downstream pipework.

If the downstream pipework or any connected plant is incapable of withstanding the maximum possible upstream pressure， then a safety valve or relief valve must be fitted on the downstream side. This valve should be set at， or below， the maximum allowable working pressure of the equipment， but with a sufficient margin above its normal operating pressure. It must be capable of handling the full volume of steam that could pass through the fully open reducing valve， at the maximum possible upstream pressure.

Pilot operation also allows the reducing valve to be relatively compact compared to other valves of similar capacity and accuracy， and allows a variety of control options， such as on-off operation， dual pressure control， pressure and temperature control， pressure reducing and surplussing control， and remote manual adjustment. Three of these variations can be seen in Figure 7.3.6.

Direct acting and pilot-operated control valves can be used to control either upstream or downstream pressures. Pressure maintaining valves （and surplussing valves） sense upstream pressure， while pressure red