Taicang Mingyu Seal CO.,LTD

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Address:Industry par-k City area, Taicang, Jiangsu Province

Tel:	0512-53116888

Tad:	801 814 802
	821 822
Foreign Trade:	807
Tel:	0512-53117788
	53117766

	53117738
	53110248
	53116030
	53116031
Fax:	0512-53117736
	53117749

ZIP:215400

Several Factors that Affect the Sealing Property

    1.Velocity of movement
    When the velocity of movement is excessive low (＜0.03 m/s), it should be co-nsidered that both the operating smoothness of the equipment and whether “creep-ing” phenomenon would be occurred or not. When the velocity of movement is exce-ssive high (＞0.8 m/s), the oil film that plays a lubricating role may be damage-d. Thus, the oil seal may become hot due to friction without good lubrication, a-nd its service life shall be significantly decreased.
    The range of the velocity of urethane or rubber oil seal is suggested to be 0.03 m/s~0.8 m/s.
    2.Temperature
    Under low temperature, the elasticity of urethane or rubber oil seal may be decreased, thus causes leakage and the oil seal as a whole shall even become hard and brittle. While at high temperature, the oil seal may be expanded and become soft, and results in quickly increasing of frictional resistance and decreasing of bearing capacity of the oil seal. The range of continuous operating temperat-ure range for the urethane or rubber oil seal is suggested to be -10℃~+80℃.
    3.working Pressure
    Seal has the minimum service pressure to request. The low pressure work must select the low friction performance, the starting resistance is small seal. Below 2.5MPa, gathers the ammonia fat seal certainly not to suit; When high pressure m-ust consider seal the bearing distorts the situation, must with guard against sq-ueezes out the elastic ring, the trench processing aspect also has the special r-equest.
    In addition, the different material quality seal has the different best work-ing pressure scope. Regarding gathers the ammonia fat seal best working pressure scope is 2.5 ~ 31.5MPa.
    The temperature, the pressure to the sealing property influence are the inci-dent cross-correlation, therefore must make the synthesis consideration. Sees the form:

Imported Polyurethane(PU) material
	maximum working pressure
maximum	temperature range	temperature range
Sport speed	-25～+80	-25～+110
0.5m/s	28MPa	25MPa
0.15m/s	40MPa	35MPa

    4.Operating medium
    Besides strictly according to produces the factory the recommendation opinion selection actuating medium, the maintenance actuating medium clean is very impo-rtant. The fat liquor aging or the pollution not only can cause in the system the part to break down, speeds up seal the aging and touches damages, moreover inte-rnal organs possibly scratch or insert seal, causes the seal failure. Therefore, must regularly inspect the fat liquor quality and its the clear fineness, and ac-cording to equipment maintenance standard replacement oil filter or fat liquor. In the fat liquor the residual air can have the high temperature in the cylinder after the high-pressured compression to cause seal to burn out, even carbonizes. In order to avoid this kind of situation occurrence, when hydraulic system move-ment initial, should carry on exhaust processing. The hydraulic cylinder also sh-ould transport the number of lines minute in the low pressure idling speed, con-firmed already arranges in the fat liquor the residual air, only then normal wo-rk.
    5.Lateral Load
    On the piston generally must install the supporting link, guaranteed the cyl-inder can withstand a bigger load. The seal and the supporting link play the com-pletely different role, the seal cannot replace the supporting link load. Has the lateral force hydraulic cylinder, must add the bearing capacity stronger support-ing link (when heavy load may use metal link), guards against seal works under t-he biased condition causes the revelation and the difference attrition.
    6.Hydrodynamic Shock
    The hydraulic pressure impact reason was very many, if the excavator digs fi-ghts suddenly bumps into the stone, the crane hoisting up or lays down the heavy item instantaneous. Is an exception outside the factor, regarding the high-pres-sured great current capacity hydraulic system, when the functional element (hyd-raulic cylinder or oil motor and so on) commutates, if cross valve performance not too good, is very easy to have the hydraulic pressure impact. The hydraulic pressure impact produces the instantaneous high pressure is possibly system wor-king pressure several times, the such high pressure can seal rend in the extrem-ely short time or partial pushes in it in the gap, creates the major damage. Ge-nerally has the cylinder which the hydraulic pressure attacks to be supposed on the connecting rod to install the cushion link and the elastic ring. The cushion link installs in seal front absorbs the majority of impact pressure, the elastic ring prevented seal pushes in the gap under the high pressure, the root is nipped badly.

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