
The products in this series produced by our company are divided into single-seat (P), sleeve (M), and double-seat (N) structures based on the valve core type, and into three types based on the actuator: diaphragm type, piston type, and bellows type.


When used for controlling downstream pressure (ZZYP-B type), its functions are pressure reduction and stabilization. When the downstream pressure exceeds the set value (desired value), the valve tends to close and eventually shuts off. When the downstream pressure is below the set value, the valve remains open to compensate pressure.
When used for controlling upstream pressure (ZZYP-K type), its functions are safety pressure relief and stabilization. When the upstream pressure exceeds the set value (desired value), the valve tends to open and fully opens. When the upstream pressure is below the set value, the valve remains closed.


ZZYP-II Type Self-Operating Pressure Regulating Valve with Commander
The ZZYP-II series nitrogen sealing device is a self-operating micro-pressure control system independently developed and manufactured by our company. It is mainly used to maintain a constant pressure of protective gas (generally nitrogen) at the top of storage tanks to prevent direct contact between the materials inside the tank and air, thereby avoiding material evaporation, oxidation, and ensuring container safety.


It is especially suitable for gas sealing protection systems of various large storage tanks. This product features energy efficiency, sensitive operation, reliable performance, and ease of operation and maintenance. It is widely used in industries such as petroleum and chemical engineering.
It does not require external energy sources and can operate without electricity or gas, making it convenient, energy-saving, and cost-effective.


The nitrogen sealing device allows for easy nitrogen supply and vent pressure setting, and can operate under continuous production conditions. The pressure detection diaphragm has a large effective area, the setting spring stiffness is small, it operates sensitively, and the device works smoothly.
To ensure the safety of the storage tank, a breather valve must be installed at the top of the tank. The breather valve serves only a safety function, avoiding the frequent and wear-prone opening and closing of nitrogen supply and vent valves found in conventional nitrogen sealing devices.












SNT Machinery (Qingdao) Co., Ltd. stands as a distinguished producer of control valves, seamlessly integrating manufacturing, design, sales, and service into a singular, cohesive operation. Situated in the vibrant city of Qingdao, Shandong province, our expansive 42,000-square-meter facility is outfitted with state-of-the-art workshops and production equipment. Recognized as a high-tech enterprise, we boast independent intellectual property rights and have adopted cutting-edge management and production methodologies from abroad. With a dynamic team of over 150 dedicated professionals, 15% of whom are specialized R&D experts and 30% hold graduate or higher degrees, we pride ourselves on innovation and excellence. Our high-quality production management team and pioneering research have enabled us to produce a vast range of top-tier valves for the petrochemical, oil, and coal chemical industries, achieving a sales milestone nearing 100 billion in 2017.
SNT has proudly obtained the TS special equipment manufacturing certificate and ISO 9001 certification, alongside the prestigious net qualification certificates from industry giants like SINOPEC, CNOOC, PETROCHINA, and SINOCHEM. Moreover, we have earned numerous national patents for our technological advancements. Our extensive capabilities allow us to design and manufacture a comprehensive range of valves in compliance with ANSI, API, DIN, BS, and JIS standards. By merging the benefits of acclaimed global valve designs with our own innovative research, we now produce an extensive array of valves, including GLOBE, high-pressure boiler blow-down valves, high-performance butterfly valves, angle-regulating valves, eccentric rotary valves, and three-eccentric center butterfly valves.
Our product lineup extends to V ball valves, high wear-resistant ball valves, high pressure steam valves, micro-flow control valves, self-operated control valves, and cryogenic valves, available in manual, power-driven, pneumatic, and hydraulic drive forms. We utilize high-quality materials such as A216WCB, A217 WC6/WC9, A351 CF8/CF8M/CF3/CF3M, with specifications ranging from 1/2" to 120", and operating pressures from ANSI 150# to 2500#. The broad working temperature span (-196ºC to 1100ºC) ensures our valves meet the demands of diverse industrial applications.
Equipped with advanced production technology management and a robust quality assurance system, SNT valves have been extensively utilized across petrochemical, oil, steel & iron, paper manufacturing, and power station industries. Our esteemed clientele includes leading enterprises such as SINOPEC QILU branch, SINOPEC Qingdao branch, CNOOC Huizhou Refinery, PETROCHINA Guangxi branch, PETROCHINA Ningxia branch, SINOPEC Qingdao Refinery, SINOPEC Changling branch, and Jinan branch, among others.
Placing our customers' success at the forefront, we are committed to crafting exceptional quality and a reputable brand. Our comprehensive quality assurance and exemplary after-sales systems ensure that SNT valves collaborate with our customers to create mutual prosperity and lasting partnerships.