What factors should be considered when purchasing all-rubber valves and semi-rubber valves?

All rubber valve and half rubber valve refers to the sealing surface material coverage of the valve, the sealing surface of the valve is completely covered by elastic materials such as rubber, half rubber valve is part of the sealing surface rubber, the rest of the metal and other materials. The following factors should be considered when purchasing:

One, medium characteristics

Type of media

For corrosive media, such as acid, alkali and other chemical solutions, the rubber sealing surface of the all-rubber valve can provide better corrosion resistance, which can effectively prevent the erosion of the medium on the sealing surface of the valve and prolong the service life of the valve.

Semi rubber valve due to the metal part of the exposure, in corrosive media may occur corrosion, generally suitable for non-corrosive or corrosive weak media, such as water, air, etc.

Temperature of medium

The rubber sealing surface of the rubber valve is easy to age and deform at high temperature, reducing the sealing performance, so it is usually suitable for low temperature media, and the general temperature range is -20℃ to 80℃.

Semi rubber valve due to the existence of metal parts, can withstand higher temperatures, suitable for medium and high temperature media, the use of temperature range is generally -40℃ to 150℃ or even higher, depending on the metal material and the heat resistance of rubber.

Particle size of medium

When the medium contains particulate impurities, the rubber sealing surface of the all-rubber valve is easy to be worn by particles, affecting the sealing effect. At this time, the semi rubber valve can be selected. The metal sealing surface part has better wear resistance and can adapt to the working condition of the medium containing particles.

Stress at work

The rubber sealing surface of the all-rubber valve is easy to be extruded or deformed under high pressure, resulting in seal failure. Therefore, the full rubber valve is generally suitable for low pressure conditions, usually the working pressure is below 1.0MPa.

Semi-rubber valves can withstand higher pressures due to the better strength and rigidity of the metal part. They are suitable for medium and high pressure conditions. The operating pressure can reach 2.5MPa and higher, depending on the construction and material of the valve.

Seal performance requirements

The rubber sealing surface of the all-rubber valve has good elasticity and flexibility, which can achieve better sealing effect. It is especially suitable for the occasions with high requirements for sealing performance, such as food, pharmaceutical and other industries, which can avoid pollution caused by media leakage.

Semi rubber valve in the sealing performance can also meet the requirements of most industrial occasions, but because of the metal and rubber binding site may exist small gap, in some high requirements for sealing occasions, may not be as ideal as the full rubber valve.

Service life

In the long-term use of the rubber sealing surface of the all-rubber valve, affected by the medium, temperature, pressure and other factors, it is prone to aging, cracking and other phenomena, so as to shorten the service life of the valve.

Due to the high durability of the metal part and the relatively slow wear and aging of the rubber part, the service life of the semi rubber valve is usually longer than that of the full rubber valve under normal use conditions.

Cost factor

The structure of the rubber valve is relatively simple, the cost of rubber material is low, so the price is usually cheaper, suitable for cost-sensitive occasions.

Semi-rubber valve contains metal parts, and the manufacturing process is relatively complex, the cost and price are generally higher, but in some occasions with high requirements for valve performance, considering its performance and service life, it still has a high cost performance ratio.

Installation and Maintenance

All rubber valves are light in weight, easy to install, and the rubber sealing surface is not easy to damage during installation. In terms of maintenance, if the rubber sealing surface of the all-rubber valve is damaged, it can generally be repaired by replacing the rubber parts, and the maintenance cost is low.

Due to the heavy metal parts of the semi-rubber valve, it is necessary to pay attention to lifting and fixing when installing. In terms of maintenance, the metal part of the semi-rubber valve needs regular anti-corrosion treatment, and the rubber part also needs to check its wear and aging, and the maintenance is relatively complex.