High Temperature and High Pressure Challenges: A Comprehensive Explanation of the Differences in Pressure Ratings between Trunnion Ball Valves and Gate Valves under ASME B16.34

In industrial application scenarios with high temperature and high pressure, the selection of valves is of crucial importance. As two common types of valves, TRUNNION BALL VALVES and gate valves have significant differences in their pressure ratings under the ASME B16.34 standard. This article will conduct an in-depth exploration of the performance characteristics of these two types of valves at different pressure levels and compare their pressure ratings in tabular form to help engineers and purchasers make wiser choices.

I. OVERVIEW OF THE ASME B16.34 STANDARD

the ASME B16.34 IS AN INTERNATIONALLY COMMONLY USED VALVE STANDARD THAT STIPULATES KEY PARAMETERS SUCH AS PRESSURE-TEMPERATURE RATINGS, TEST REQUIREMENTS,and material applicability of valves. THIS STANDARD IS APPLICABLE TO MULTIPLE TYPES OF VALVES, INCLUDING BALL VALVES, GATE VALVES, GLOBE VALVES, ETC., and is widely used in industries such as petroleum, chemical engineering, and natural gas. According to ASME B16.34, the pressure rating of a valve will vary depending on factors such as material, temperature, and design.

II. BASIC CHARACTERISTICS OF TRUNNION BALL VALVES AND GATE VALVES

(1) Trunnion Ball Valves
A trunnion ball valve is a high-performance ball valve. Its valve body design adopts a trunnion support structure, which can withstand relatively high pressure and temperature. The main advantages of ball valves are rapid opening and closing, good sealing performance, and low fluid resistance. Trunnion ball valves are usually suitable for occasions that require frequent operation and high sealing requirements, such as in oil and gas transmission and chemical pipelines.

(2) Gate Valves
A GATE VALVE is a type of valve that controls the on-off of fluid by the up-and-down movement of the gate. Its main advantages are reliable sealing performance, low fluid resistance, and a wide range of applications. Gate valves are usually used in fully open or fully closed situations and are not suitable for flow regulation. In high-temperature and high-pressure working conditions, the sealing performance and strength of gate valves are key considerations.

III. COMPARISON OF PRESSURE RATINGS

According to the ASME B16.34 standard, the pressure ratings of trunnion ball valves and gate valves at different pressure levels are shown in the following table:

It can be seen from the above table that the pressure ratings of trunnion ball valves at each pressure level are slightly higher than those of gate valves. This is mainly because the design structure of trunnion ball valves enables them to better withstand high pressure, and at the same time, their sealing performance can remain stable under high-pressure environments.

IV. PERFORMANCE IN HIGH TEMPERATURE AND HIGH PRESSURE ENVIRONMENTS

(1) Trunnion Ball Valves
Trunnion ball valves perform excellently in high temperature and high pressure environments. Their trunnion support structure can effectively disperse pressure and reduce stress concentration on the valve body. In addition, the sealing surfaces of ball valves usually adopt high-performance sealing materials, such as PEEK or PTFE, which can maintain good sealing performance at high temperatures. For example, when the temperature reaches 200 °C, the pressure rating of trunnion ball valves can still remain at a relatively high level.

(2) Gate Valves
The performance of gate valves in high temperature and high pressure environments is also relatively reliable, but their sealing performance and strength are limited by materials and design. The sealing of gate valves mainly relies on the close fit between the gate and the valve seat. High temperature may cause the material to expand, thus affecting the sealing effect. In addition, the opening and closing torque of gate valves is relatively large, and higher power support is required when operating in high-pressure environments.

V. SELECTION SUGGESTIONS

When choosing trunnion ball valves or gate valves, the following factors need to be considered comprehensively:

• Working Condition Requirements: If frequent operation and rapid opening and closing are required, it is recommended to choose trunnion ball valves; if they are mainly used in fully open or fully closed situations, gate valves are a better choice.

• Pressure and Temperature: According to the pressure and temperature range of the actual working conditions, refer to the ASME B16.34 standard to select valves with appropriate pressure levels. Trunnion ball valves perform better in high temperature and high pressure environments, but their costs are relatively high.

• Sealing Performance: If extremely high sealing performance is required, it is recommended to choose trunnion ball valves, especially in situations where sealing needs to be maintained under high pressure.

• Maintenance Cost: The structure of trunnion ball valves is relatively complex, and the maintenance cost is relatively high; the structure of gate valves is simple, and maintenance is relatively easy.

VI. SUMMARY

There are certain differences in the pressure ratings of TRUNNION BALL VALVES and GATE VALVES under the ASME B16.34 standard. TRUNNION BALL VALVES perform more excellently in high temperature and high pressure environments. However, GATE VALVES also have their unique advantages in many application scenarios due to their simple and reliable structures and lower costs. Engineers and purchasers should comprehensively evaluate and choose the most suitable valve type according to specific working condition requirements, budgets, and maintenance capabilities.