What is a double seal?

Double (or dual) mechanical seals are designed to ensure maximum sealing safety. These seals virtually eliminate leakage of the fluid or gas being handled in pumps or mixers. Double seals provide a level of safety/zero emissions compliance not possible with single seals.

What is the difference between a 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 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 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 secondary seal?

Definition of 'secondary sealing'

There is primary sealing of the space between the inner wall of the tank and the floating roof, and secondary sealing above the primary seal. Secondary sealing is a system of wiper seals used in floating roof tanks.

Mechanical seal working animation types of mechanical seal

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.

Why use a double mechanical seal?

Double (or dual) mechanical seals are designed to ensure maximum sealing safety. These seals virtually eliminate leakage of the fluid or gas being handled in pumps or mixers. Double seals provide a level of safety/zero emissions compliance not possible with single seals.

How many types of mechanical seals are there?

8 Types of Component Mechanical Seals.

How many sealing faces does a tandem seal have?

These seals often use two rotating seal faces and two stationary seal faces. A fluid is provided between these two seals at a lower pressure than the sealed fluid (known as buffer fluid) or at a pressure higher than the sealed fluid (known as barrier fluid).

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 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.

What is slurry seal?

Slurry seal is a thin asphalt overlay / seal coat that will fill in small cracks and surface imperfections to give the roadway a uniform color and texture. Most importantly it seals the pavement, thus preventing the infiltration of water, which is the most frequent cause of pavement failure.

What is meant by a mechanical seal?

Mechanical seals are devices that are used to provide a seal at the point of entry or exit of a rotating shaft. Typically it is used to prevent the leakage of one high pressure fluid into a lower pressure fluid.

What is a mechanical seal on a pump?

A mechanical seal is simply a method of containing fluid within a vessel (typically pumps, mixers, etc.) where a rotating shaft passes through a stationary housing or occasionally, where the housing rotates around the shaft.

What is inboard in mechanical seal?

Inboard Mechanical Seals

The term Inboard seals simply refers to seals that are mounted inside of a pumps stuffing box, to a shaft or sleeve and are mounted independently as individual parts. Unlike Cartridge seals which is a unitized set of rotating, stationary, sleeve and gland components.

What is the difference between barrier fluid and buffer fluid?

When this fluid is unpressurized, it forms a buffer between the pumped fluid and atmosphere and is commonly referred to as a buffer fluid. When pressurized, it forms a barrier between the pumped fluid and atmosphere and is known as a barrier fluid.

What is API plan 11?

API Plan 11 recirculates flow from a high‐pressure section of the pump, typically the discharge piping, through a flow control orifice to the seal. Plan 11 is the default flush plan for most pumps. API Plan 11.

What is seal cavity pressure?

Confirm seal chamber pressure is at least 345 kPa (50 psi) above the fluid's vapor pressure. From: Forsthoffer's Best Practice Handbook for Rotating Machinery, 2011.

What is a Type 1 mechanical seal?

Suitable for a wide range of service conditions ranging from water and steam to chemicals and corrosive materials, the Type 1 mechanical seal is ideal for use in pumps, mixers, blenders, agitators, air compressors, blowers, fans and other rotary shaft equipment.

What is a monolithic seal?

Monolithic Seal Faces

A seal with an inserted face will utilises a metal rotary holder in order to transmit the shaft torque to the seal face. The fact that the face and holder material have different thermal expansion coefficients is a disadvantage of inserted face design.

What are the three basic parts of a mechanical seal?

Typically, a mechanical seal contains:

Secondary static seals, V-rings, O-rings or wedges. Static seal or stationary component.

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 dry mechanical seal?

Dry gas seals are non-contacting, dry-running mechanical face seals that consist of a mating (rotating) ring and a primary (stationary) ring. When operating, lifting geometry in the rotating ring generates a fluid-dynamic lifting force causing the stationary ring to separate and create a gap between the two rings.

What is gland packing?

The gland packing is a contact-type sealing element. Compared with other types of shaft seals, they are adjustable and suitable for use with pressures and circumferential speeds higher than those radial shaft seal rings are used for (see also Shaft seal).