218 SPN Mechanical Seals for Pumps Pusher Seals

(1)Features
The SPN is used as an automatic refi ll unit
and for barrier fl uid pressurization in seal
circuits. It is possible to use pneumatic or
electric power, or a combination of both
for the pressurization. The refi ll unit tank
is designed for pressureless operation
and is equipped with a level switch and
a sight-glass (automatic refi ll unit also
available as an option). The refi ll unit has
all pipework as far as the distributor unit.
Separate components are installed in the
seal circuit to cool and to circulate the
barrier medium. The SPN range is available
in 2 basic versions:
SPN1000: Vessel capacity 20 or 40 liters
SPN3000: Vessel capacity 40, 60 or
200 liters

Barrier fl uid pressure regulation for the
SPN1000 via pressure switch to the pump
control.
The SPN3000 is equipped with a pressure
regulator for maintaining a constant barrier
pressure level.

(2)Advantages
• Reliable mode of operation: should the pump be switched off,
the barrier fl uid pressure will be maintained for a limited time by an integrated accumulator
• Membrane accumulator acts as a pulsation damper/barrier fl uid storage tank
• SPN3000: maintains constant barrier pressure irrespective of hysteresisinduced pressure fl uctuations of the pressure switch
• Visual level indicator via sight-glass on the vessel

(3)Functional description
SPN automatic refi ll units differ from
an SPA in that they perform just two of
the four basic functions of a barrier fl uid
system, namely barrier fl uid pressurization
and leakage compensation. It is possible
to use a piston pump with either electric or
pneumatic power for pressurization of the
barrier medium. Should all the pumps fail, the
pressure will be maintained in the refi ll unit
for a limited time to ensure that pressurization
of the barrier fl uid circuit is maintained. How
long the pressure is maintained will depend
on the storage volume and the leakage losses
to be compensated.

(4)Materials
Parts in contact with the medium are made
of stainless steel.
Secondary seals and elastomers are
resistant to water, demineralized water and
hydraulic oil.

(5)Recommended applications
• Chemical industry
• Petrochemical industry
• Oil and gas industry
• Refi ning technology

Operating and installation diagram for an automatic refi ll unit.

(6)Product variants

The SPN automatic refi ll unit can be supplied with a wide range of system components and engineered systems to meet specifi c customer requirements.

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).