Correct installation of gate valves is vital for both system safety and the long life and efficient operation of the valve. Even simple mistakes made during the installation process can lead to serious malfunctions, leaks or even loss of pressure in the future. For this reason, pre-assembly preparation, correct alignment, selection of suitable fasteners and post-assembly testing stages should be meticulously applied. Valve type, fluid properties, temperature and pressure values should also be taken into consideration.
Before installation, the valve should be checked for any problems such as cracks, rust, deformation or obstruction in the slide movement. The flange surfaces must be clean, flat and aligned to ensure that the gasket fits properly. The valve should generally be installed in the closed position to minimize the risk of damage to internal parts during installation. In addition, sufficient space must be left around the valve, especially for rising stem type valves, vertical space must be provided for the stem to move freely. All these steps ensure that the gate valve is leak-free, safe and efficient after installation.
Preparation Before Assembly
The preparations to be made before starting the gate valve installation are critical for both the healthy progress of the installation and the trouble-free commissioning of the system. First of all, it should be checked whether the valve to be used is fully suitable for the system requirements. In this context, valve diameter, connection type (flanged, threaded, welded), material type and operating pressure-temperature values must be compatible with the system. The technical data sheets of the manufacturer should be examined in detail and valve selection should be verified in the light of this information.
Immediately before installation, the valve must also be physically inspected. The outer surface of the valve should be carefully examined for cracks, dents or deformations, and the inside of the valve should be carefully examined for problems such as rust, foreign matter or stuck bolts. Valves that have been in stock for a long time or have not been protected outdoors may have deformation, dust or moisture damage on the sealing surfaces. Such situations may lead to leakage, blockage in slide movement or opening-closing problems in the future. Therefore, cleaning, inspection and function testing prior to installation are steps that should not be skipped for safe completion of the installation.
Suitable Mounting Direction and Location
The choice of direction and position in gate valve installation is extremely important for the healthy operation and long life of the valve. Generally, gate valves are installed parallel to the vertical flow direction, i.e. in such a way that the gate valve can work in harmony with gravity. This mounting direction facilitates the free movement of the gate and improves sealing performance by fitting more evenly on the gate seal faces. However, some gate valve models can also be used in horizontal pipelines. In such cases, the position of the gate and the orientation of the valve cover must be carefully adjusted; otherwise, the gate may be forced and bent, the sealing surfaces may be pressed unevenly and leakage or wear may occur in the system.
In addition, sufficient working space must be left around the valve. Especially in rising stem type gate valves, vertical clearance is essential for the stem to move upwards. If this space is not provided, the gate cannot be fully opened and valve performance is seriously reduced. Again, for maintenance and service operations, planning should be made so that there is easy access around the valve. During installation, the valve body should not be subjected to bending, straining or bearing the weight of the pipe; such errors may cause leaks and mechanical failures both during installation and in the future. Correct orientation and position are the basis for stable and efficient operation of the gate valve.
Flanged Connection and Gasket Application
Gate valves are usually installed with flanged connection system and making this connection correctly is vital for sealing and mechanical durability. The most important issue in flange connection is that the flange surfaces should be smooth, clean and parallel. Crooked, rusty or rough flange surfaces prevent the gasket from seating correctly between the valve and pipe, which can lead to leakage, gasket crushing and even mechanical failure over time. Before installation, the flange surfaces should be thoroughly cleaned with a wire brush, cloth or special cleaning products, leaving no oil, rust or dust on the surface.
The choice of gasket should be appropriate for the pressure, temperature and fluid type of the system. Commonly used gasket materials include PTFE (teflon), graphite, rubber (EPDM, NBR), spiral wound metal gaskets. The appropriate material should be selected according to the application area, otherwise the sealing feature may deteriorate in a short time. When tightening the bolts, cross (X pattern) tightening method must be applied and each bolt must be tightened with equal torque. This ensures equal pressure on the gasket surface and prevents leaks caused by unbalanced tightening. If possible, the tightening values specified by the manufacturer should be adhered to by using a torque wrench. Thanks to these careful applications, both the valve connection is robust and long-term sealing is ensured in the system.
Should the Valve be Open or Closed?
Which position – open or closed – the valve should be in during gate valve installation is an important subject of discussion in terms of installation safety and system health. In line with general practice and manufacturer recommendations, gate valves should be installed in closed position. The main reason for this is to prevent dust, foreign bodies or metal particles from entering the valve during installation. A gate valve in closed position protects the internal structure and especially prevents damage to the sealing surfaces. In addition, mechanical impacts or misalignments that may occur during assembly cause less damage to the gate.
In some cases, however, it is advocated that the bolt should be mounted in the semi-open position. The rationale for this approach is to avoid compression of the sealing surfaces and to allow the slide to move more freely after assembly. However, this method is only possible under clean ambient conditions and with high-precision equipment. In practice and in field applications, this method is generally not recommended as there is a higher risk of damage to the sealing surfaces when the slide is open. In summary, mounting the gate valve in the fully closed position is considered the most common and safe method for a safe and trouble-free installation.
Alignment and Support
Correct alignment and the use of appropriate pipe support systems in gate valve installation play a critical role in both extending the life of the valve and ensuring trouble-free operation of the system. The pipeline where the valve will be installed and the flanges of the gate valve must be on axis, straight and parallel. Otherwise, the flanges will be forced together during installation, which may cause uneven pressure on the gasket surfaces, leakage or bending of the flange screws. Especially with large diameter valves, even a small misalignment can prevent the correct operation of the gate mechanism and cause the valve not to close completely.
In addition, the gate valve should not be installed in such a way that it carries the weight of the pipeline. Over time, the pipes may create an extra load on the gate valve with their own weight or the pressure of the fluid passing through them. This may cause cracks in the valve body, openings in the flange joints or deformation of the gate. To eliminate such loads, suitable pipe supports or suspension systems should be used before and after the valve. In addition, in systems where temperature changes are intense, the expansion movements of the pipes should not put pressure on the valve. Flexible fittings such as expansion compensators can be used for such cases. Proper alignment and support is the key to safe, leak-free and long-lasting operation of the gate valve.
Testing and Commissioning
After the assembly process is completed, the valve must be tested. First, a tightness test is applied. In this test, the valve is completely closed and checked for any leakage from the sealing surfaces under system pressure. Then the valve is opened and it is observed whether the bolt moves freely.
If the system will be automated, electric or pneumatic actuator connections should be tested and valve responses should be measured. If the system is integrated to PLC or SCADA system, correct signal transmissions, position indicators and safety limit switches should be verified. The test phase is critical to prevent future system problems.
Common Assembly Errors and Precautions
Errors made during installation can seriously affect the performance of the gate valve. The most common installation errors are as follows:
- Improper flange alignment
- Tightening bolts with unequal torque
- Failure to use suitable gasket
- Restriction of the shaft’s range of motion
- Loading of pipe weight on the valve
To avoid such errors, installation must be carried out by trained personnel, the manufacturer’s installation instructions must be followed and the testing phase must not be skipped.
Correct Installation, Long Lasting Use
The basic condition for obtaining the highest performance and longest service life in gate valve systems is to perform the installation process correctly and consciously from the first stage. Even small mistakes made during assembly can lead to major malfunctions, leaks or even complete system shutdown in the future. For this reason, the manufacturer’s manuals must be followed, all flange connections must be properly aligned, the correct gasket materials must be preferred and the connection bolts must be tightened with equal torque. In addition, access should be provided around the valve, sufficient space should be left for shaft movement and care should be taken to ensure that the weight of the pipe does not fall on the valve.
Every gate valve installation made by following these basic rules guarantees safe and efficient operation of the system. Correct installation not only extends valve life, but also minimizes maintenance and failure costs in the system. Leakage problems are prevented, slide movements are smooth and operational continuity is maintained. In addition, thanks to the tests to be carried out after the system is commissioned, possible installation errors can be detected and eliminated early. In short, a correctly installed gate valve is an indispensable step in terms of operational safety, energy efficiency and long-lasting system use.
