{"product_id":"1pcs-for-qg-40-qg-40b-qg-50-air-compressor-servo-loading-cylinder-inlet-valve","title":"QG-40\/QG-40B\/QG-50 Air Compressor Servo Loading Cylinder Inlet Valve","description":"\u003carticle class=\"koeed-container\"\u003e\n  \u003c!-- Engineer's Quick Brief --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch2 style=\"color: #16c8c8;\"\u003eEngineer's Quick Brief\u003c\/h2\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eOptimized Load\/Unload Control:\u003c\/strong\u003e The \u003cstrong\u003eQG-40 and QG-50 series\u003c\/strong\u003e inlet valves utilize a precision pneumatic servo cylinder to swiftly transition rotary screw compressors between loaded (compressing) and unloaded (idling) states, minimizing energy waste.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eIntegrated Anti-Blowback System:\u003c\/strong\u003e Features a robust internal check valve (non-return valve) that instantly seals upon shutdown or power loss, preventing compressed air and lubricating oil from spitting back through the air filter.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eDirect Replacement Match:\u003c\/strong\u003e Designed with standard flange footprints for seamless integration into \u003cstrong\u003e30kW to 55kW (40HP - 75HP)\u003c\/strong\u003e industrial screw air compressors, ensuring rapid maintenance turnarounds.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- SEO Introduction --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch3 style=\"color: #16c8c8;\"\u003eQG-40 \/ QG-40B \/ QG-50 Servo Cylinder Inlet Valve\u003c\/h3\u003e\n    \u003cp\u003eThe \u003cstrong\u003eQG-40, QG-40B, and QG-50 Servo Loading Inlet Valves\u003c\/strong\u003e are heavy-duty pneumatic suction controllers engineered specifically for \u003cstrong\u003erotary screw air compressors\u003c\/strong\u003e. Acting as the respiratory system of your compressor, this assembly determines exactly how much ambient air is allowed into the air-end. Driven by a highly responsive servo cylinder and typically paired with a normally-closed (NC) solenoid control system, it ensures your compressor only works when system pressure drops below the set threshold. Manufactured from high-density, corrosion-resistant cast aluminum, these valves provide durable, leak-free performance in continuous-duty manufacturing and industrial air plants.\u003c\/p\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- Technical Specifications Table --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch3 style=\"color: #16c8c8;\"\u003eTechnical Specifications\u003c\/h3\u003e\n    \u003cdiv style=\"overflow-x: auto;\"\u003e\n      \u003ctable style=\"width: 100%; border-collapse: collapse; border: 1px solid #eeeeee; font-size: 14px;\"\u003e\n        \u003cthead\u003e\n          \u003ctr style=\"background-color: #16c8c8; color: #ffffff;\"\u003e\n            \u003cth style=\"padding: 12px; text-align: left;\"\u003eSpecification Parameter\u003c\/th\u003e\n            \u003cth style=\"padding: 12px; text-align: left;\"\u003eDetail \/ Value\u003c\/th\u003e\n          \u003c\/tr\u003e\n        \u003c\/thead\u003e\n        \u003ctbody\u003e\n          \u003ctr style=\"background-color: #f4fcfc;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eSeries Models\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003eQG-40 \/ QG-40B \/ QG-50\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #fafafa;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eCompatible Compressor Type\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003eOil-Injected Rotary Screw Air Compressors\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #f4fcfc;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eTypical Power Match\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e30 kW to 55 kW (approx. 40 HP to 75 HP)\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #fafafa;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eActuation Mechanism\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003ePneumatic Servo Cylinder (Control Air Actuated)\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #f4fcfc;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eStandard Valve State\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003eNormally Closed (Opens on vacuum\/control signal)\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #fafafa;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eWorking Pressure Range\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e0.5 MPa - 1.5 MPa (5 to 15 Bar)\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #f4fcfc;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eMain Housing Material\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003eHigh-Strength Cast Aluminum Alloy\u003c\/td\u003e\n          \u003c\/tr\u003e\n          \u003ctr style=\"background-color: #fafafa;\"\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003e\u003cstrong\u003eIntegrated Safety Features\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd style=\"padding: 10px; border-bottom: 1px solid #eeeeee;\"\u003eAnti-blowback Check Valve, Internal Bleed\/Vent Port\u003c\/td\u003e\n          \u003c\/tr\u003e\n        \u003c\/tbody\u003e\n      \u003c\/table\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- Application Matrix --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch3 style=\"color: #16c8c8;\"\u003eIndustrial Application Matrix\u003c\/h3\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003ePreventative Overhaul:\u003c\/strong\u003e Essential replacement component during the 8,000-hour major service interval for medium-sized rotary screw compressors.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eManufacturing Plants:\u003c\/strong\u003e Ensures stable pneumatic supply for CNC machining centers, robotic assembly lines, and industrial packaging equipment by maintaining precise load\/unload cycles.\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eAir-End Protection:\u003c\/strong\u003e Acts as the primary physical barrier, preventing destructive reverse-rotation of the screw rotors during emergency stops.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- Troubleshooting \u0026 FAQ --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch3 style=\"color: #16c8c8;\"\u003eTroubleshooting \u0026amp; Maintenance FAQ\u003c\/h3\u003e\n    \u003cdiv class=\"koeed-faq\"\u003e\n      \u003cp\u003e\u003cstrong\u003eQ: Why is oil spitting out of my compressor's air intake filter when it shuts down?\u003c\/strong\u003e\u003cbr\u003e\n      A: This is a classic symptom of a failed check valve within the inlet valve assembly. When the compressor stops, internal pressure forces air and oil backward. If the \u003cstrong\u003eQG inlet valve's internal spring or sealing O-ring\u003c\/strong\u003e is worn, it fails to slam shut, causing \"blowback\". The entire valve or a comprehensive rebuild kit must be installed.\u003c\/p\u003e\n      \n      \u003cp\u003e\u003cstrong\u003eQ: The compressor is running, but it won't build pressure (fails to load). Is the inlet valve broken?\u003c\/strong\u003e\u003cbr\u003e\n      A: Possibly. If the \u003cstrong\u003eservo loading cylinder\u003c\/strong\u003e is jammed due to moisture\/rust, or if the control solenoid valve supplying air to the servo cylinder has failed, the inlet valve will remain closed. Check the control air line and ensure the solenoid is receiving the correct voltage before condemning the physical valve.\u003c\/p\u003e\n\n      \u003cp\u003e\u003cstrong\u003eQ: What is the difference between the QG-40 and QG-50 models?\u003c\/strong\u003e\u003cbr\u003e\n      A: The primary difference lies in the internal bore size and the mounting flange diameter. The \u003cstrong\u003eQG-50\u003c\/strong\u003e allows for a higher volumetric flow rate (CFM\/m³\/min), making it suitable for larger air ends (e.g., 55kW\/75HP machines), whereas the \u003cstrong\u003eQG-40\u003c\/strong\u003e is typically used on 30kW-37kW units. Always measure your existing bolt hole pitch before ordering.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- Cross-Reference \u0026 Selection --\u003e\n  \u003csection class=\"koeed-section\"\u003e\n    \u003ch3 style=\"color: #16c8c8;\"\u003eCross-Reference Guide\u003c\/h3\u003e\n    \u003cdiv style=\"overflow-x: auto;\"\u003e\n      \u003ctable style=\"width: 100%; border-collapse: collapse; font-size: 13px;\"\u003e\n        \u003ctr style=\"border-bottom: 1px solid #eee;\"\u003e\n          \u003ctd style=\"padding: 8px; width: 30%;\"\u003e\u003cstrong\u003eSystem Compatibility\u003c\/strong\u003e\u003c\/td\u003e\n          \u003ctd style=\"padding: 8px;\"\u003eWidely compatible with Chinese and international generic air ends (e.g., Baosi, Hanbell, Rotorcomp) utilizing standard flange footprints.\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr style=\"border-bottom: 1px solid #eee;\"\u003e\n          \u003ctd style=\"padding: 8px;\"\u003e\u003cstrong\u003eFunctional Category\u003c\/strong\u003e\u003c\/td\u003e\n          \u003ctd style=\"padding: 8px;\"\u003ePneumatic Suction Controller \/ Unloader Valve Assembly\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd style=\"padding: 8px;\"\u003e\u003cstrong\u003eRelated Maintenance Parts\u003c\/strong\u003e\u003c\/td\u003e\n          \u003ctd style=\"padding: 8px;\"\u003eMinimum Pressure Valve (MPV), Load Solenoid Valve (220V\/24V), Thermostatic Valve Kits.\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/table\u003e\n    \u003c\/div\u003e\n  \u003c\/section\u003e\n\n  \u003c!-- Structured Data (FAQPage) --\u003e\n  \u003cscript type=\"application\/ld+json\"\u003e\n  {\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n      {\n        \"@type\": \"Question\",\n        \"name\": \"Why is oil spitting out of my compressor air filter on shutdown?\",\n        \"acceptedAnswer\": {\n          \"@type\": \"Answer\",\n          \"text\": \"This blowback is caused by a failure of the integrated check valve inside the inlet valve assembly. Worn springs or seals prevent it from closing fast enough to block the pressurized oil\/air mixture.\"\n        }\n      },\n      {\n        \"@type\": \"Question\",\n        \"name\": \"Why won't my screw compressor build pressure?\",\n        \"acceptedAnswer\": {\n          \"@type\": \"Answer\",\n          \"text\": \"If the compressor runs but doesn't build pressure, the servo loading cylinder on the inlet valve may be stuck closed, or the solenoid controlling the servo air is faulty.\"\n        }\n      },\n      {\n        \"@type\": \"Question\",\n        \"name\": \"What is the difference between QG-40 and QG-50 inlet valves?\",\n        \"acceptedAnswer\": {\n          \"@type\": \"Answer\",\n          \"text\": \"The main differences are the internal bore diameter and mounting flange size. QG-50 supports higher airflow volumes for larger horsepower compressors compared to the QG-40.\"\n        }\n      }\n    ]\n  }\n  \u003c\/script\u003e\n\u003c\/article\u003e\n\n\u003cstyle\u003e\n  .koeed-container { line-height: 1.6; color: #333; font-family: -apple-system, BlinkMacSystemFont, \"Segoe UI\", Roboto, Helvetica, Arial, sans-serif; }\n  .koeed-section { margin-bottom: 30px; }\n  .koeed-section h2, .koeed-section h3 { margin-bottom: 15px; border-bottom: 1px solid #eeeeee; padding-bottom: 5px; }\n  .koeed-faq p { margin-bottom: 15px; }\n  .koeed-section table th, .koeed-section table td { border: 1px solid #eeeeee; padding: 10px; }\n\u003c\/style\u003e","brand":"KOEED","offers":[{"title":"Default Title","offer_id":43858637226169,"sku":"305023167071","price":149.42,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0268\/8476\/7929\/files\/1PCS_FOR_QG_40_QG_40B_QG_50_Air_compressor_Servo_loading_cylinder_inlet_valve___KOEED__1.webp?v=1774694512","url":"https:\/\/koeed.com\/sr\/products\/1pcs-for-qg-40-qg-40b-qg-50-air-compressor-servo-loading-cylinder-inlet-valve","provider":"KOEED","version":"1.0","type":"link"}