Technological innovation – GS slider-type control valve

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The GS slide-type control valve was uniquely designed and manufactured by the German company Schubert&Salzer Control Systems. It has strong versatility, and its flow capacity is the same as that of a single-seat control valve. The GS control valves manufactured by S&S Company come in two inherent flow characteristics: linear and equal percentage, which are also the most commonly used flow characteristics in current control valve applications. With few exceptions for certain accessories, most of the components of the GS slide-type control valve are manufactured in-house by the company, which ensures the product’s high reliability and excellent performance. The following sections briefly outline some of the features of the GS slide-type control valve series. I. Actuator Section: The actuator for GS slide-type control valves comes in three main options. 1. Multi-spring pneumatic diaphragm actuator: This is a popular option and manufacturing technique used by major control valve manufacturers around the world today. This multi-spring design allows for the use of different air supply pressures and spring ranges by simply adjusting the number of springs. The combination is flexible; the weight, volume of the spring, as well as the complexity of its manufacturing are significantly reduced, and the linearity of the stroke within the spring’s range is easier to control and ensure. 2. Cylinder piston actuator: A return spring is installed on the cylinder piston. Compared to cylinder pistons with two-way gas supply, it offers better control stability, requires less reliance on positioners, and enables the valve to be quickly returned to a safe position as required by the process in case of a failure. This eliminates the need for some complex fault-handling mechanisms and valve-position assurance systems, thereby reducing investment costs and the space required for installing the control valve system. 3. Electric actuator: A variety of electric actuators are available as options, featuring motors with different power and voltage levels, thus fully meeting the requirements of various users. It also has an extremely fast response time. II. Valve Body Section: The most important aspect of the GS slider-type control valve lies in the design of its valve body, which represents the essence of its design. In the design of its valve body, the GS slide-type control valve incorporates many advantages of other valve types: the lightweight structure of butterfly valves, the shearing characteristics of V-port ball valves, the easy control associated with the straight-stroke operation of single-seat valves, and extremely low leakage rates. It utilizes two model plates equipped with throttling slots to achieve variations in the valve’s flow cross-sectional area. 1. Lightweight structure: (1) The GS slider-type control valve uses a clamping installation method, eliminating the bulky valve body and mounting flanges found in single-seat valves, thereby reducing the weight of the valve body as well as the amount of material used for it. (2) Since a sliding plate (with throttle grooves) is used as the valve element in this valve, the stroke of the valve element corresponds to the width of those throttle grooves; thus the stroke is very short. Moreover, the unbalanced force acting on it is much smaller than that in a single-seat valve (1/10 of the unbalanced force in a single-seat valve). As a result, the actuator required for this valve is much smaller compared to those used in other types of control valves such as single-seat valves, which also helps to reduce the overall weight of the valve. 2. Precise machining (1) A clever and well-thought-out design reduces the difficulty of machining. The flow characteristics of control valves such as the single-seat type are determined by the curved surface shape of the valve spool, whereas those of slide-type control valves are determined by the geometric shape of the throttle grooves in the moving slide and the fixed plate. Therefore, in terms of processing difficulty, it is easier compared to other types of control valves (or in other words, the processing difficulty is low); the reliance on and requirements for processing equipment are also reduced, making it very easy to ensure high processing precision. (2) The sealing performance is extremely high. The sealing surface of the GS slide-type control valve is the plane of the two slides. It makes it very easy to achieve a highly refined finish on the contact surface between the two plates (for example, a finish as smooth as a mirror). The sealing leakage rate of the GS control valve is less than 0.001% of the Kv value. Moreover, it features that the longer its service life, the better its sealing performance (this is mainly because during the opening and closing process of the valve, as the valve plate moves up and down, the sealing surfaces of the moving slide plate and the fixed plate grind against each other automatically due to the pressure difference in the pipeline and before and after the valve). 3. The inventive throttling flow cross-section: The throttling flow cross-section of the GS slider-type control valve is the throttling groove on the valve plate. These throttle slots enable a more stable flow pattern of the fluid as it passes through, reducing turbulence, noise, and erosion caused by flow across the throttle section compared to straight-stroke single-seat valves. It also has a shearing effect; as the valve approaches closure, the sharp edges of the porous throttle grooves in the two plates come into close contact and scrape against each other, resulting in shearing, which enables it to have a wide range of applicable scenarios. At the same time, the skateboard experiences less unbalanced force when fluid flows through it, allowing it to have a greater capacity to overcome pressure differences compared to equivalent actuators. The stroke of the GS slide-type control valve is the width of the throttle orifice on the slide; it is extremely short, allowing for rapid response. It is particularly suitable for applications where speed is required for the opening and closing of the valve. The maximum adjustable ratio of the GS slide-type control valve can reach 40:1, with an actual adjustable range of over 30:1. This is because the unbalanced forces acting on the GS slide-type control valve are much smaller compared to those in single-seat valves, being almost negligible. The controllable range is from 2% to 100% of the stroke; unlike single-seat valves, there is no need to set the minimum flow rate at a valve opening of more than 10%. For the GS slide-type control valve, a conservative value for the minimum flow rate can be set at a valve opening of 3% or more. Such an adjustable ratio range can fully meet the user’s requirements, enabling the control valve to operate in an ideally controllable range. The GS slide-type control valve is designed with only two flow characteristics: linear and equal percentage orifice patterns. In various production processes, control valves that utilize these two types of flow characteristics are used in the vast majority of cases, demonstrating great practicality. III. Humanized design and excellent cost-performance ratio in terms of selection options: The designers and manufacturers of the GS slider-type control valves take into full account various application scenarios and operating environments during the design and manufacturing process. For most application conditions and environments that are not particularly demanding, a standard configuration can be chosen; for environments with corrosive properties, a corrosion-resistant stainless steel casing can be used to protect the actuator ； Under the same specifications, it is possible to change the flow capacity and update spare parts by replacing the fixed plate and the moving slide. For the GS slide-type control valve, the manufacturer offers a wide range of materials suitable for use in both the valve body and its internal components: carbon steel and stainless steel (316). Additionally, depending on the operating conditions of the user, surface welding with Stellite alloy can be performed to enhance the resistance of the internal components to cavitation, corrosion, and wear, thereby meeting the user’s requirements. For some particularly aggressive corrosive media, Hastelloy is an available option. The sealing fillers for the moving parts of the valve stem include V-type polytetrafluoroethylene, graphite, and bellows. Springs made of stainless steel are installed at the bottom of the stuffing box, and the elastic force of these springs is used to maintain a stable packing compression force. IV. Energy savings and reduced consumption: “Instrumented” control valves. Since the unbalanced forces acting on the valve core are very small, it is sufficient to use smaller pneumatic or electric actuators to meet the driving force requirements, thereby reducing consumption of air and electricity. The GS slider-type control valves are equipped with integrated intelligent valve positioners, which enable easy installation and adjustment, provide rapid response, and feature a sophisticated design. They meet the highest demands placed on control valves in various process industries, thus achieving instrumented control of these valves. In summary, the designers and manufacturers of the GS slider-type control valve have carried out optimal optimizations throughout the design and manufacturing process, while also giving full consideration to its applicability and the convenience for users in maintenance. When selecting the valve, the operating conditions must be taken into full consideration; once the right model is chosen, it can be installed and used. Under normal operating conditions, the GS slide-type control valve ensures long-term operation with minimal requirements for regular maintenance. Compared to straight-stroke single-seat valves, GS slide-type control valves use less material; the larger the diameter, the lower the material consumption. As a result, they offer excellent cost-performance and strong competitiveness in terms of both initial investment costs and subsequent labor expenses.