130 DGS Mechanical Seals for Pumps Pusher Seals

(1)Features
• Gas-lubricated
• Unidirectional or bidirectional available
• Ready-to-fit cartridge unit
• Single, dual, tandem and tandem with intermediate labyrinth available

(2)Advantages
The proven Dry Gas Seal for pressures up to 100 bar
(1,450 PSI). Due to simple components a reliable and
economical solution for low pressure applications.
Application single seal: The simplest seal is a Dry Gas
Seal in single arrangement. This seal is used in case that
due to the nature of the product gas no additional back
up seal is required. Separation seals as labyrinths, radial
clearance seals or CobaSeal are optionally available.
This version is used as an emission-free arrangement with
a corresponding flare/vent connection. Primary leakage is
then discharged with the separating gas to the flare/vent.
In the case of dirty gases the gas to be sealed has to be
filtered in addition and conveyed to the seal chamber via
connection "A". The resulting gas flow from the sealing
compartment prevents any dirty/wet gas gas entering the seal

(3)Operating range (see note on page 1)
Shaft diameter: Ds1 = 29 ... 264 mm (1.14" ... 10.39")
Pressure: p = 0 ... 100 bar (1,450 PSI)
Temperature: t = -20 °C ... +200 °C (-4 °F ... +392 °F)
Sliding velocitiy: vg = 0.6 ... 200 m/s (2 ... 656 ft/s)

(4)Item Description
1 Seal face, stationary
2 Seat, rotating
3 Thrust ring
4 Spring
5 Shaft sleeve and seat retainer
6 Intermediate sleeve
7, 8 Housing (adapted in size to the installation space)
9 Carbon ring type separation seal
10 Labyrinth
11 Intermediate labyrinth
A Product flushing
B Flare
C Buffer gas
D Separating gas
S Vent

(5)Materials
Seal face: Silicon carbide (Q1) with DLC coating
Seat: Silicon carbide (Q1) with DLC coating
Secondary seals: FKM (V) or other materials depending on
product gas composition
Metal parts: 1.4006 or other stainless steels.

(6)Standards and approvals
• NACE

(7)Recommended applications
• Oil and gas industry
• Refining technology
• Petrochemical industry
• Hydrocarbon gas
• Ammonia
• Nitrogen
• Air
• Centrifugal compressors
• Turbo expanders
• Blowers

(8)Product variants
DGS Tandem seal
Application: Where small product leakages of process
gas are admissible, e.g. on gas pipeline compressors.
Seal on the atmosphere side acting as a safety seal. The
tandem arrangement provides a particularly high degree of
operational safety. The seal on the product side and the seal
on the atmosphere side are able to absorb the complete
pressure differential. Under normal operating conditions
the full pressure is reduced only by the seal on the product
side. The space between the seal on the product side and
the seal on the atmosphere side is cleared by a connection
"B" to the primary vent (flare). The pressure differential to
be sealed by the seal on the atmosphere side equals the
primary vent pressure, so the leakage to the secondary vent
(atmosphere) is very low. If the main seal fails, the second
seal acts as a safety seal.

DGS Tandem seal with intermediate labyrinth
Application: Where product leakages to the atmosphere
as well as buffer gas leakages to the product are
inadmissible, e.g. on H2, ethylene or propylene
compressors. With this version the product pressure to be
sealed is reduced via the seal on the product side. The
entire process gas leakage is discharged via connection
"B" to the primary vent. The seal on the atmosphere side
is pressurized with buffer gas (nitrogen) via connection
"C". The pressure of the buffer gas ensures that a nitrogen
flows via the labyrinth to the flare/vent outlet.

DGS Dual seal
Application: Where product leakages to the atmosphere
are inadmissible and tandem arrangements are not
suitable because of too small product gas pressures.
Buffer gas leakages into the product must be admissible
(buffer pressure p3 > p1). This seal is used when a
neutral buffer gas of suitable pressure is available. Typical
applications are to be found mainly in the chemical
industry, e.g. on HC gas compressors. A buffer gas, e.g.
nitrogen, is fed between the seals via connection "C" at a
higher pressure than the product pressure. One part of the
buffer gas leakage escapes to the atmosphere side and
the other part to the product.

Dimensions in mm

We have large stock, so our delivery is very fast.
For example,if products are standarded, the delivery time is one week.
Our company and factory addrss: Ningbo City, Zhejiang Province,China.
Our city has a large port and an airport, so its transportation is very convenient.

Question1: What are the prices of your products?
Answer: For each model, the unit price is listed on the website, but what is displayed on the website is only the average market price. For specific models, you can contact us for further consultation and negotiation.

Question 2: Are you a factory or a trade company?
Answer: We are a factory with top sales for the trade service.
Question 3: What is the minimum order quantity for each order?
Answer: For products of regular models, the minimum order quantity is at least five. We welcome you to test the quality of our products and services through placing trial orders. Looking forward to the long-term cooperation with you.

Question4: What is your company's service tenet?
Answer: Quality first, service upmost. We promises that if there is any problem with the quality of the product, or if the product is damaged during the transportation, our company will be responsible for compensation, regardless of the ordder turnover value.

Question5: Can I try to get a SAMPLE before the order?
Answer: Sure. Our company will provide you with samples for free, but you will have to pay for the international delivery (freight collect payment).