What is a tandem seal?

A tandem seal is the Grundfos name for a shaft seal system where an additional sealing chamber has been mounted on the existing shaft seal. The purpose of the sealing chamber in a tandem seal pump is to guarantee that liquid does not leak from the pump housing.

What is a tandem mechanical seal arrangement?

Tandem seals are two single seals mounted in the same direction. Tandem seals are used for toxic or flammable liquids that require a buffer or safety zone. If the inboard seal fails, a high pressure alarm will activate to provide a warning that the inboard seal has failed.

How many sealing faces does a tandem seal have?

The tandem seal, which is probably the most common, consists of two single seals oriented in the same direction.

When would you use a dual lip seal?

Double seals provide a level of safety/zero emissions compliance not possible with single seals. This is essential when pumping or mixing a dangerous or toxic substance. These seals are increasingly used by companies to meet specific environmental goals or emissions requirements.

Where are double seals used?

Double mechanical seals are commonly used in the following circumstances: If the fluid and its vapors are hazardous to the operator or environment, and MUST be contained. When aggressive media are used at high pressures or temperatures. For many polymerizing, sticky media.

Tandem Seals on CR pumps from Grundfos – explained

What is difference between single seal and double seal?

Summarizing the Differences

A single seal has two faces, while a double seal has four. A double seal divides faces into rotating and stationary. Single seals use the pump's fluid as a lubricant, while double seals have a dedicated buffer or barrier liquid.

What is double mechanical seal?

A double mechanical seal is a type of mechanical seal with two primary seals or sets of faces, it can operate in various arrangements with a) a barrier (containment) between the sets of faces or b) a buffer (mixing).

What is a triple lip seal?

The triple lip seal incorporates the technology of a membrane-like PTFE sealing element designed for high viscosity applications and other fluids without compromising sealing capability. Despite its versatility, the triple lip seal has its limitations and best uses.

What is the difference between single and double lip seals?

The single lip is vital to the function of the seal by containing the oil, grease or lubricant. The only difference between a single and double lip is the additional rubber lip on the top of the oil seal which helps prevent dust or dirt from coming close to the shaft.

How many types of mechanical seals are there?

The Three Types of Mechanical Seals

Three types of mechanical seals are used in process equipment: Cartridge. Component. Air.

What is secondary seal?

The secondary process seal assembly with rupture indication sensor is designed to prevent the passage of gases under pressure through conduit, cables and conductors, while providing immediate notification of a dangerous, potentially explosive seal rupture.

What is primary seal and secondary seal?

Primary seals acts as first line of barrier whereas secondary seals works as a safety line incase of failure of primary seal. Usually primary seal fluid will be operation gas (mixes with operation) and secondary seal will have nitrogen (inert gas) that goes to flare taking away any traces of leakage in primary seal.

What is a single mechanical seal?

A single mechanical seal is a type of mechanical seal which consists of one primary seal and it seals from process to atmosphere. There is always some leakage either to atmosphere or into process depending on the process pressure.

Why do mechanical seals fail?

A mechanical seal might fail due to poor lubrication, or no lubrication at all. When there is no liquid around the seal it will be subjected to increased amounts of friction which will increase the temperature inside the pump.

What is seal arrangement?

Arrangement 3 seals are defined as two mechanical seals with the barrier fluid between the seals maintained at a pressure higher than the seal chamber pressure (Figure 4). In this arrangement, both the inner and outer seals are sealing the barrier fluid.

What are the different types of oil seals?

Should you grease oil seals?

Never assemble an Oil Seal dry. Both the shaft and the Oil Seal have to be lubricated with oil or grease in advance. This eases the assembly and ensures lubrication from the beginning. If Oil Seals with fixed dust lips are being used, the space be- tween the sealing lip and the dust lip may also be filled max.

How much pressure can a lip seal hold?

Most oil, grease, and bearing seals with elastomeric seal lips are designed for zero pressure but will provide adequate service up to 3psi (0.2bar). Higher pressures will push the lip against the shaft and cause excessive friction and wear and rapid failure of the seal.

What is the difference between mechanical seal and lip seal?

A lip seal is also known as an oil seal or a rotary shaft seal. Oil seals or rotary shaft seals and mechanical seals are designed for moving parts.

What is single seal?

A single mechanical seal consists of stationary and rotating seal faces that are made from one hard and one softer material. A single mechanical seal offers considerable cost and energy savings when used instead of gland packing.

What is balanced and unbalanced seal?

A seal with a balance ratio less than 100 percent is called a balanced seal. A seal with a balance ratio greater than 100 percent is called an unbalanced seal. Most balanced seals have a balance ratio between 60 and 90 percent. Most unbalanced seals have a balance ratio between 110 and 160 percent.

Do mechanical seals require seal water?

Mechanical seals require clean water, or other compatible liquid, for the lubrication of the seal faces. The faces in a typical mechanical seal are lubricated with a boundary layer of gas or liquid between the faces.

What is slurry seal?

A slurry seal is the application of a mixture of water, asphalt emulsion, aggregate (very small crushed rock), and additives to an existing asphalt pavement surface. A slurry seal is similar to a fog seal except the slurry seal has aggregates as part of the mixture.

What is double seal in endodontics?

What is Double Seal technique: This is a technique which involves the use of two restorative materials together to overcome the disadvantages caused by the use of a single restorative material.