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The YOKOTA Non-External-Flushing Mechanical Seal is a new type mechanical seal which requires no external sealing water supply, being superior in corrosion resistance and wear resistance, and is easily installed into pumps.
This mechanical seal has been adopted for pumps running under severe conditions in industrial fields such as electric power plants, and has been rated highly as an epoch-making mechanical seal.
This mechanical seal is also suitable for seawater and slurry liquid.
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Advantages of the YOKOTA Non-External-Flushing Mechanical Seal
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Reduction of equipment costs
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Piping for external sealing water and electrical instrumentation are not required.
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Reduction of running costs
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The sealing water cost is not required. (For example, you can save 0.3 litre minute of water which amounts to as much as 150 tons a year.)
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The cost for maintaining sealing water in the case of a double mechanical seal or the cost for adjusting leakage in the case of gland packing is eliminated.
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Power consumption can be reduced because of the low friction on the sliding surface.
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The water imbalance in a plant process due to mixture of sealing water into pumping water can be prevented. And treatment of leaked sealing water is not required.
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A comparison of running costs
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The cumulative totals of running costs for continuous operation of pumps with a shaft diameter of 48mm and a 30kW motor equipped with a Non-External-Flushing Mechanical Seal, double mechanical seal, or gland packing, are as shown below:
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Features
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Stable seal performance for a variety of purposes because of the stationary balance type structure.
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Easy installation without remodeling a pump casing even when installing to a pump that previously used gland packing.
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Malfunction due to adhesion of slurry, corrosion, or abrasion is not possible since the pins and springs do not contact liquids.
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Due to the self-alignment mechanism between its loose ring and rotary ring, the sliding surface of the loose ring floats and efficiently follows the sliding surface of the rotary ring.
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Excellent wear resistance to high density slurry liquid because the SiC of the sliding surface has excellent hardness, sliding performance, and corrosion resistance.
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YST130N is used for the parts that contact liquids. This is the duplex type stainless steel YOKOTA has developed, and can be used for various liquids because of its remarkable corrosion resistance, wear resistance, and mechanical strength.
(For details of YST130N, please refer to this page.)
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Supply of sealing water, such as industrial water, from the outside is not required.
(Please use self-flushing method in order to prevent sliding parts from possible dry-operation caused by a cavity generated within the stuffing box due to generation of negative pressure in the case of self-priming operation, or mixture of air in the case of force pumping operation.)
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Structure
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Stable seal performance for a variety of purposes because of the stationary balance type structure.
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Easy installation without remodeling a pump casing even when installing to a pump that previously used gland packing.
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Malfunction due to adhesion of slurry, corrosion, or abrasion is not possible since the pins and springs do not contact liquids.
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Due to the self-alignment mechanism between its loose ring and rotary ring, the sliding surface of the loose ring floats and efficiently follows the sliding surface of the rotary ring.
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Performance
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Condition of a self-priming limestone slurry pump in an electric power plant after 6 months |
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As you can see, there are no problems despite slurry adhesion.
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Pump specifications
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1.5m3/min x 42m x 1750rpm
Liquid property: Limestone slurry 20wt%
Shaft diameter: 48mm
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Running condition
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Suction head: -4m
Running period: 6 consecutive months (including 21 stops and starts)
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Measurement of abrasion on the seal surface
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Seal surface
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Amount of abrasion
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Rotary ring
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0.05mm or less
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Loose ring
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0.05mm or less
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No abnormalities found in the pins and springs of the loose ring. |
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Coarseness of the seal surface after operation
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The conditions of the surface coarseness are very good.
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Applications
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The YOKOTA Non-External-Flushing Mechanical Seal can be used for almost all kinds of liquid. It proves excellent performance especially when used in pumps dealing with the following liquids:
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Electricity:
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Smoke discharging desulfurizer, Seawater drawing, Waste water treatment, other
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Electronics:
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Ultra-pure water production, Waste liquid treatment, other
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Chemical:
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Acid liquid, Alkaline liquid, Solvent, other
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Sewage:
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Polluted water, Sludge, Liquid containing earth and sand
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Others:
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Seawater, Condensed seawater, Liquid containing slurry, other
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