Bottom valves

In industrial installations where secure fluid intake, mechanical filtration, and protection against backflow are required, bottom valves offer a technically proven and compact solution. Positioned at the lowest point of a tank, vessel or vertical pipeline, these valves combine the function of a suction strainer with a non-return valve, ensuring that the fluid entering the system is free from solid contaminants and that pressure stability is maintained within the pipeline.

ZETKAMA’s tank bottom valve, designated Fig. 935 (zBOT), is engineered specifically for such use. The design supports media flow only in one direction — from the tank into the pipe — while simultaneously preventing reverse movement of fluid. In systems where protection of pumps, process lines, and system hydraulics is critical, this element improves efficiency, reduces maintenance needs and ensures uninterrupted operation under standard working conditions. Thanks to its robust construction and suitability for multiple mounting orientations, the bottom outlet valve offers both flexibility in installation and high performance in continuous service.

Functional role in fluid systems

The operational principle of bottom ball valve–type solutions is based on three primary functionalities: mechanical filtration, flow direction control, and system stabilization. First, the valve is equipped with a perforated stainless steel suction strainer, which physically blocks solid impurities present in the fluid. These can include particles, sediment, or rust fragments, particularly common in older or unfiltered water systems. By preventing such materials from entering the pipeline, the valve protects downstream components such as pumps, check valves, and flow meters from wear, clogging or malfunction.

Second, the integrated check valve mechanism ensures that media can only flow in one direction — from the tank toward the pipeline. When the pump stops or system pressure drops, the check mechanism automatically closes, stopping reverse flow. This prevents unintended emptying of the pipeline, eliminates the risk of cavitation, and helps maintain pressure balance within the installation.

Third, the valve stabilizes the hydraulic conditions within the system. By reducing turbulence at the intake point and dampening pressure surges during pump start-up, it contributes to the safe and smooth operation of the entire circuit. The non-perforated bottom plate of the screen enhances sealing against the tank surface and improves the structural integrity of the suction system.

Design features and materials of construction

ZETKAMA’s bottom valves are constructed to meet the demands of long-term use in standard industrial environments. The body of the valve is made from grey cast iron EN-GJL-250, a material valued for its compressive strength, vibration damping and thermal resistance. The cast structure is coated with epoxy paint, which protects the outer surfaces against moisture, corrosion, and mechanical wear during transport or operation.

Inside the valve, a spring-loaded check mechanism ensures responsive closure and tight sealing. The sealing element is made from EPDM, a material selected for its chemical resistance to neutral fluids such as drinking water, glycol, or standard process water. The screen, which forms the primary barrier against impurities, is made from AISI 302 stainless steel and features a regular perforation pattern for optimized flow and dirt retention. Its design allows for efficient cleaning of the medium while minimizing flow resistance.

The valve can be delivered in two configurations:
– as a complete unit with check valve and suction screen
– or as a standalone suction strainer for cases where non-return functionality is not needed.

This modularity increases the versatility of the solution and enables the valve to be adapted to different system needs without design compromise.

Operating parameters and dimensional standards

The ZETKAMA bottom valve (zBOT) is rated for pressure class PN10 and is available in nominal diameters from DN50 to DN300. Its standard operating temperature range extends from –10°C to +80°C, which covers most water-based and glycol-based applications in industrial and utility systems. In installations where only the suction screen is used (without the check valve), the allowed working temperature extends up to +200°C, provided the material compatibility with the medium is confirmed. The valve’s flanged ends are compliant with EN 1092-2 (PN10 drilling), enabling it to be directly connected to other standardized pipeline components without the need for modifications. 

ZETKAMA also provides a detailed table of Kvs values, which indicate the valve’s flow capacity depending on size. These values range from:

• DN50 – Kvs 99 m³/h
• DN80 – Kvs 240 m³/h
• DN100 – Kvs 360 m³/h
• DN150 – Kvs 670 m³/h
• DN200 – Kvs 1040 m³/h
• DN250 – Kvs 1610 m³/h
• DN300 – Kvs 2365 m³/h
  

The overall height of the valve unit, weight, and screen mass are all specified in the technical documentation to support system planning and load calculations.

Fluids, compatibility and installation guidelines

ZETKAMA bottom valves are designed for use with chemically neutral fluids under standard working conditions. Approved and compatible media include:

• Drinking water
• Industrial water
• Glycol-based mixtures
• Non-aggressive process fluids

The product is not intended for use with aggressive chemicals, abrasive slurries, or media containing large solids or reactive compounds. For any application outside of the recommended scope, especially involving elevated temperatures or unconventional substances, material compatibility and operational limits must be reviewed against the full technical specification. A key advantage of the zBOT valve is that it can be mounted in any working position. This allows engineers and installers to incorporate it into both horizontal and vertical systems, as well as in tight spaces or retrofitted installations. The valve is designed for maintenance-free operation and does not require adjustment or recalibration during normal use.

Long-term reliability and practical advantages

The simplicity and mechanical integrity of the ZETKAMA bottom valve design make it a dependable component for installations where stable suction, mechanical filtration, and backflow prevention are required simultaneously. By combining three functions in one unit — strainer, check valve, and sealing plate — it eliminates the need for separate devices, reduces installation time, and minimizes potential leakage points.

The use of robust materials such as cast iron and stainless steel, together with EPDM sealing elements, ensures high resistance to wear and corrosion. The standardized flange connection simplifies integration into new or existing systems, and the ability to order the screen separately provides additional design flexibility. The bottom valve is not only technically reliable but also operationally efficient — it maintains fluid cleanliness, protects equipment, stabilizes system pressure, and contributes to reduced lifecycle costs by requiring no maintenance.

Efficient tank drainage and safe intake control

By ensuring clean media intake, stabilizing the hydraulic environment, and blocking reverse flow, ZETKAMA’s bottom valves play a critical role in maintaining process safety and operational efficiency. Suitable for various industrial installations handling water or glycol, the bottom outlet valve stands out for its durability, modular construction, and compliance with European pressure and connection standards. It is a trusted component in any system where secure intake from the base of a tank or vessel is essential.