Floating Ball Valve vs. Trunnion Ball Valve: Which Is Better for High-Pressure Service?

Introduction

In high-pressure conditions, valve selection is directly related to system safety and maintenance costs. In scenarios such as oil wells, power plant steam, chemical reactors, etc., the high-pressure bearing and sealing performance of valves is a core requirement. Floating ball valve and trunnion ball valve are the two most commonly used ball valves in high-pressure scenarios. The former is economical and convenient, while the latter is stable and reliable. Improper selection can easily lead to leakage, jamming, and even safety accidents. This article combines practical experience to break down the core differences and adaptation scenarios between the two, helping to quickly avoid selection errors.

What is a Floating Ball Valve

The core feature of a floating ball valve is that the valve core can "float", the structure is simple, and the valve core is connected to the valve stem but without a fixed support shaft. It relies on the pressure of the medium and the clamping force of the valve seat to achieve positioning. When opened, the valve core is suspended and the medium flows smoothly through the valve core through-hole; When closed, the medium pressure pushes the valve core to squeeze the valve seat, achieving self sealing. Its advantages lie in small size, light weight, few parts, easy installation and low cost, without the need for large equipment assistance. However, under high-pressure conditions, the short board protrudes: when the medium pressure exceeds the limit, the valve core is prone to slight deformation, and long-term wear of the sealing surface can easily cause leakage. Stainless steel and carbon steel are commonly used as materials, and PTFE and graphite are used for valve seats, which are suitable for medium and low pressure scenarios. However, their deformation resistance is insufficient and they cannot adapt to ultra-high pressure.

What is a Trunnion Ball Valve

Trunnion ball valve, also known as fixed ball valve, has a valve core fixed by ear shaft, without axial displacement. The sealing relies on both pre tightening force and medium pressure to ensure basic sealing even without medium pressure. Its structure is relatively complex, with additional ear shaft support and pre tensioning components, large volume, heavy weight, high manufacturing cost, and a purchase price much higher than that of floating ball valves. But the high pressure stability is extremely strong, the valve core is fixed without displacement, the sealing surface is uniformly stressed, and the leakage risk is low. The valve seat is mostly made of hard alloy, suitable for extreme scenarios such as ultra-high pressure, strong corrosion, and high-frequency switches, with a longer service life and can avoid significant losses caused by valve failure.

Key Differences in High-Pressure Service: Floating vs. Trunnion Ball Valves

Design and Sealing Mechanism

Floating ball valves are centered around minimalism, without ear shafts or pre tightening mechanisms, and rely on medium pressure to self tighten and seal. The principle is simple and the cost is low. The sealing effect is still acceptable in medium and high pressure scenarios, but it is prone to deformation and leakage when the pressure exceeds the standard; The sealing surface is mostly a soft seal or a combination of soft and hard materials, with weak resistance to high-pressure impact and pressure fluctuations. The trunnion ball valve is centered around "stability", with the ear shaft fixed valve core limiting displacement and dual sealing ensuring high-pressure stability. The sealing surface is mostly made of metal hard seal, and the pre tightening force can be flexibly adjusted to adapt to high-pressure and high-temperature working conditions; But the structure is complex, and the installation accuracy of sealing components requires high precision, requiring professional personnel to operate.

Pressure Handling Capacity

The upper limit of the floating ball valve pressure is limited. The commonly used models are compatible with PN16-PN100, and the specially designed models can reach PN160. Under high pressure, the valve core and seat wear quickly, and the sealing performance deteriorates significantly. If the pressure exceeds the standard, it is easy to fail directly. It is strictly prohibited to use it in ultra-high pressure scenarios. The trunnion ball valve is designed specifically for high pressure, with commonly used models compatible with PN100-PN320. It can be customized for higher pressure levels and can withstand long-term ultra-high pressure impacts. The valve core has no displacement and the sealing surface is wear-resistant, ensuring stable sealing even in the event of high pressure fluctuations. It is the only preferred choice for ultra-high pressure scenarios.

Maintenance Requirements

The maintenance threshold of trunnion ball valve is low, with few parts and a simple process. Ordinary workers can operate them, mainly checking the sealing surface and cleaning impurities in the valve chamber. Maintenance is carried out every 6-12 months in medium and high pressure scenarios; However, under high pressure, the sealing surface wears out quickly and requires frequent replacement of the valve seat, resulting in high maintenance costs and affecting production. The maintenance of the trunnion ball valve is meticulous, involving multiple components such as the ear shaft and pre tightening mechanism, requiring professional personnel and specialized tools. The single maintenance cost is high, but the wear is slow and the maintenance cycle is long,without the need for frequent component replacement. It is suitable for key scenarios with high stability requirements and the ability to bear high maintenance costs.

Cost and Application Suitability

Floating ball valves have outstanding cost-effectiveness, low manufacturing and procurement costs, easy installation, suitable for bulk procurement, and adaptable to medium and high pressure, non critical working conditions such as civil high-pressure water supply, ordinary chemical pipelines, and auxiliary pipelines for small and medium-sized boilers, without the need to bear additional costs for complex working conditions. The cost of trunnion ball valve is relatively high, with a purchase price of 1.5-3 times that of floating ball valve. It has a large volume and high installation difficulty, which increases the installation cost; But adapting to ultra-high pressure and critical working conditions, such as underground oil wells, high-pressure steam pipelines, and nuclear chemical equipment, can avoid significant losses caused by valve failure and provide better long-term cost-effectiveness.

Flow Resistance and Pressure Drop

The through hole of the  floating ball valve core is consistent with the diameter of the pipeline, without any unnecessary obstruction, with low flow resistance and reduced pressure, suitable for medium and high pressure scenarios with high medium flow rate and high pressure drop requirements; Slight deformation of the valve core under high pressure may lead to a reduction in the through-hole and a slight increase in resistance. Due to the occupation of valve chamber space by the trunnion ball valve, the flow resistance and pressure drop of the ear shaft ball valve are 5% -10% higher than those of the floating ball valve. However, the difference can be ignored in ultra-high pressure scenarios, and its stable operation can avoid indirect pressure loss caused by leakage, making it more reliable overall.

Long-Term Durability in Cyclic Operations

Floating ball valves have average durability. Under high pressure and high frequency switching, the friction between the valve core and valve seat intensifies, the sealing surface ages, and the valve core is prone to fatigue deformation. The service life under high pressure conditions is 1-3 years, suitable for medium and high pressure scenarios with low switching frequency and stable operating conditions. The trunnion ball valve has strong durability. The trunnion is fixed so that the sealing surface is evenly stressed. The hard sealing material is wear-resistant and anti-aging. It can still operate stably under high pressure and high frequency operation, and its service life can reach 5-10 years. It is suitable for high frequency switching and ultra-high pressure critical scenarios with complex working conditions.

Scenario-Based Selection Guide for High-Pressure Systems: Floating vs. Trunnion Ball Valves

Cost-Effective Medium-Pressure Applications

Floating ball valves are preferred for medium pressure conditions, non critical pipelines, cost sensitivity, and limited maintenance resources. Its simple structure and high cost-effectiveness can meet the needs of scenarios such as high-pressure water supply for civilian use, switching of ordinary chemical media, and fluid control in non core areas, minimizing overall operating costs.

Ultra-High-Pressure and Critical Service Environments

Under ultra-high pressure conditions and critical pipelines, which require extremely high stability and can bear high costs, it is necessary to choose ear ball valves. The stable sealing and high-pressure bearing capacity of the ear shaft ball valve are the core guarantees for avoiding safety accidents and reducing losses in scenarios such as oil wells, high-pressure steam power generation, and nuclear chemical reaction devices.

Floating Ball Valve vs. Trunnion Ball Valve: At-a-Glance Comparison

LIXIN Ball Valve Advantages for High-Pressure Applications

Having been in the high-pressure valve industry for many years, LIXIN Ball Valve has been deeply rooted in the high-pressure field, focusing on solving the pain points of high-pressure adaptation for conventional ball valves. In response to the shortcomings of floating ball valves and ear shaft ball valves, special optimizations and upgrades have been made. Both floating ball valves and ear shaft ball valves can adapt well to high-pressure scenarios, making up for many shortcomings of conventional products. In on-site use, they have always had a good reputation. In terms of material, LIXIN has undergone strict screening and upgrading, making it less prone to deformation under high pressure. The sealing surface of the ear shaft ball valve is made of hard alloy and also coated with a special wear-resistant layer. And all materials have undergone strict testing, with strength, wear resistance, and corrosion resistance fully meeting the requirements of high-pressure working conditions, so there is no need to worry about materials not meeting the marked standards. LIXIN provides customized solutions based on the actual working conditions on site. Simply put, whether you choose a floating or ear shaft type, LIXIN ball valves can balance reliability and cost-effectiveness, without worrying about compatibility issues or spending extra money on extra performance. They can provide strong support for stable operation of high-pressure systems, reducing later troubles and costs.

Conclusion

The high-pressure selection of floating ball valves and trunnion ball valve can be complex or simple, with two core points: working condition matching and demand balance. As long as these two points are grasped, a reasonable choice can be made without further hesitation. If your operating condition is medium pressure and the pressure level is between PN16 and PN100, a floating ball valve is the optimal solution. Its low cost and low maintenance threshold can meet the needs of medium control while saving overall operating costs, making it highly cost-effective. High pressure applications never pursue "omnipotence", but rather "precision" - without having to pay the low-cost price of floating ball valves for ultra-high pressure scenarios; There is no need to bear the high cost pressure of trunnion ball valve for medium pressure scenarios, as many stability performance cannot be used and it is purely a waste of cost. When selecting, as long as you clarify the pressure level, switching frequency, maintenance resources, and cost budget of your own operating conditions, and combine the core differences between the two types of ball valves, you can make a reasonable choice. LIXIN ball valves, whether floating or ear shaft, can adapt to different high-pressure working conditions with material upgrades, precision control, and scene customization, balancing reliability and economy, ensuring the safe and stable operation of high-pressure systems, and solving everyone's selection and use pain points.

FAQS

Q1: Can floating ball valves be temporarily used for ultra-high pressure conditions?

A: Not recommended. The anti deformation ability of the floating ball valve core is limited. Temporary ultra-high pressure can cause deformation of the core and wear of the sealing surface, which can easily lead to sealing failure in the long run. Special ear shaft ball valves are required for ultra-high pressure.

Q2: Is the high cost of ear shaft ball valves worth investing in?

A: It depends on the scene. Non critical medium voltage scenarios do not require investment; Ultra high voltage and critical scenarios are worth it, and its stability can avoid safety accidents and production losses, with better long-term cost-effectiveness.

Q3: What is the difference in maintenance cycle between the two under high pressure conditions?

A: The floating ball valve needs to be checked and the valve seat replaced every 6-12 months; Check the ear shaft and pre tightening mechanism of the ear shaft ball valve every 1-2 years, and the sealing surface does not need to be replaced frequently.

Q4: Can Lixin high-pressure ball valves be adapted to corrosive high-pressure media?

A: Sure. We can customize valve cores and seats made of corrosion-resistant materials such as Hastelloy and Monel to avoid the risk of corrosion failure.

Q5: What are the common reasons for sealing failure of floating ball valves under high pressure?

A: The core is the deformation of the valve core and the wear of the sealing surface, which is often caused by pressure exceeding the design threshold or frequent operation.

Q6: Is the ear shaft of the ear shaft ball valve easily damaged?

A: It's not easy. Its ear shaft is made of high-strength material, accurately installed and fixed, and has no displacement under high pressure. Under normal maintenance, its service life can reach more than 5 years.

Q7: Are there any installation space requirements for both?

Answer: Yes. Floating ball valve has a small volume and is suitable for narrow spaces; The ear shaft ball valve has a large volume and heavy weight, and sufficient installation and maintenance space needs to be reserved.

Q8: Under high pressure conditions, which type of ball valve switch is more labor-saving?

A: Trunnion ball valves are more labor-saving. The valve core is fixed without displacement, and there is no need to overcome the squeezing force of the medium on the valve core when switching, resulting in lower operating resistance.

Q9: Can the floating ball valve be upgraded to adapt to ultra-high pressure?

A: No. The structural design determines that its deformation resistance is limited, and even after upgrading, it cannot withstand ultra-high pressure impacts for a long time. Therefore, the ear ball valve needs to be replaced.

Q10: Is the customization cycle for Lixin ball valves long?

A: Not long. Conventional customization scenarios can be completed within 7-15 days, while complex ultra-high pressure and strong corrosion scenarios can be customized within 30 days without affecting project progress.