Axial Piston Fixed Motor A2FNM for Fan Drives and Flywheel Mass

Transcription

1 Electric Drives and Controls Hydraulics Linear Motion and ssembly Technologies Pneumatics Service xial Piston Fixed Motor 2FNM for Fan Drives and Flywheel Mass RE 91007/ /16 Data sheet Series 61 Sizes 10 to 125 Nominal pressure 300 bar Maximum pressure 350 bar Open circuit Contents Ordering code for standard program 2 Technical data 3 Port plate with integrated check valve 8 Dimensions size 10, 12, 16 9 Dimensions size 23, 28, Dimensions size Dimensions size 56, Dimensions size 80, Dimensions size 107, Installation instructions 15 General instructions 16 Features Fixed motor with axial tapered piston rotary group of bentaxis design, for hydrostatic drives in open circuits For use in mobile and stationary applications The output speed depends on the flow of the pump and the displacement of the motor. The output torque increases with the pressure differential between the high and low-pressure side and with increasing displacement Finely graded sizes provide for good adaptation to the required drive application With integrated check valve for discharge of flywheel mass. High efficiency and cost-effective start-up efficiency High power density High speed Low-noise operation Compact dimensions and low mass Robust bearings --For absorbing radial forces --For saving on collar bearings --For direct mounting of fan wheel

2 2/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Ordering code for standard program 2FN M / 61 V xial piston unit ent-axis design, fixed, nominal pressure 300 bar, maximum pressure 350 bar, 01 with single direction of rotation for fan drive and flywheel mass 2FN Operating mode 02 Motor M 03 Size (NG) Geometric displacement, see table of values on page Series 04 Series 6, index Direction of rotation Viewed on drive shaft clockwise R counter-clockwise L Seals 06 FKM (fluor-caoutchouc) V 07 Drive shaft Splined shaft DIN 5480 Z Parallel keyed shaft, DIN 6885 P Mounting flange 08 ISO hole 09 Port plate for service lines 1) Direction of rotation Threaded ports and, bottom ccw m cw m m m Threaded ports and, ccw m m m m m m 1x side and 1x rear cw m m m m m m SE flange ports and, ccw m m m 1x side and 1x rear cw m m m SE flange ports and, bottom ccw m m 34 cw m m 10 Valves Integrated check valve without flushing notch with standard flushing notch from return line 11 Standard / special version Standard version Special version -S Note Short designation X on a feature refers to a special version not covered by the ordering code. = vailable m = On request = Not available 1) Fastening thread or threaded ports, metric

3 2FNM Series 61 RE 91007/02.11 osch Rexroth G 3/16 Technical data Hydraulic fluid efore starting project planning, please refer to our data sheets RE (mineral oil), RE (environmentally acceptable hydraulic fluids) and RE (HF hydraulic fluids) for detailed information regarding the choice of hydraulic fluid and application conditions. The fixed motor 2FNM is not suitable for operation with HF hydraulic fluid. If HF, HFC and HFD or environmentally acceptable hydraulic fluids are being used, the limitations regarding technical data and seals mentioned in RE and RE must be observed. When ordering, indicate the hydraulic fluid that is to be used. Selection diagram Viscosity ν [mm 2 /s] VG 22 VG 32 VG 46 VG 68 VG ν opt Details regarding the choice of hydraulic fluid The correct choice of hydraulic fluid requires knowledge of the operating temperature in relation to the ambient temperature: in an open circuit the reservoir temperature. The hydraulic fluid should be chosen so that the operating viscosity in the operating temperature range is within the optimum range (ν opt. ), see shaded area of the selection diagram. We recommended that the higher viscosity class be selected in each case. Example: t an ambient temperature of X C, an operating temperature of 60 C is set in the circuit. In the optimum operating viscosity range (ν opt., shaded area), this corresponds to the viscosity classes VG 46 or VG 68; to be selected: VG 68. Note The case drain temperature, which is affected by pressure and speed, is always higher than the reservoir temperature. t no point of the component may the temperature be higher than 115 C, however. The temperature difference specified below is to be taken into account when determining the viscosity in the bearing. If the above conditions cannot be maintained due to extreme operating parameters, please contact us Temperature t [ C] t min = -40 C Hydraulic fluid temperature range t max = +115 C Viscosity and temperature Viscosity [mm 2 /s] Temperature Comment Transport and storage T min -50 C T opt = +5 C to +20 C up to 12 months with standard factory preservation up to 24 months with long-term factory preservation (Cold) start-up 1) n max = 1600 T St -40 C t 3 min, without load (p 50 bar), n 1000 rpm Permissible tempe rature difference DT 25 K between axial piston unit and hydraulic fluid Warm-up phase n < 1600 to 400 T = -40 C to -25 C at p nom, 0.5 n nom and t 15 min Operating phase Temperature difference DT = approx. 12 K between hydraulic fluid in the bearing and the case drain fluid at port T. Maximum temperature 115 C in bearing 103 C measured at port T Continuous operation n = 400 to 10 n opt = 16 to 36 T = -25 C to +90 C measured at port T, no restriction within the permissible data Short-term operation n min < 10 to 5 T max = +103 C measured at port T, t < 3 min, p < 0.3 p nom FKM shaft seal 1) T +115 C see page 4 1) t temperatures below -25 C, an NR shaft seal is required (permissible temperature range: -40 C to +90 C).

4 4/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Technical data Filtration of the hydraulic fluid Finer filtration improves the cleanliness level of the hydraulic fluid, which increases the service life of the axial piston unit. To ensure the functional reliability of the axial piston unit, a gravimetric analysis of the hydraulic fluid is necessary to determine the amount of solid contaminant and to determine the cleanliness level according to ISO cleanliness level of at least 20/18/15 is to be maintained. t very high hydraulic fluid temperatures (90 C to maximum 115 C), a cleanliness level of at least 19/17/14 according to ISO 4406 is necessary. Direction of flow Direction of rotation, viewed on drive shaft cw ccw to to Speed range No limit to minimum speed n min. If uniformity of motion is required, speed n min must not be less than 50 rpm. See table of values on page 6 for maximum speed. If the above classes cannot be achieved, please contact us. Shaft seal Permissible pressure loading The service life of the shaft seal is affected by the speed of the motor and the case drain pressure. It is recommended that the average, continuous case drain pressure of 3 bar absolute at operating temperature is not exceeded (maximum permissible case drain pressure 6 bar absolute at reduced speed, see diagram). Short-term (t < 0.1 s) pressure spikes of up to 10 bar absolute are permitted. The service life of the shaft seal decreases with an increase in the frequency of pressure spikes. The case pressure must be equal to or greater than the external pressure on the shaft seal. Perm. pressure pabs max [bar] 6 NG56, NG80, 90 NG107, NG10, 12, 16 NG23, 28, 32 NG Speed n [rpm] Temperature range The FKM shaft seal may be used for case drain temperatures from -25 C to +115 C. Note For application cases below -25 C, an NR shaft seal is required (permissible temperature range: -40 C to +90 C). State NR shaft seal in plain text when ordering. Please contact us.

5 2FNM Series 61 RE 91007/02.11 osch Rexroth G 5/16 Technical data Operating pressure range Pressure at service line port or Nominal pressure p nom 300 bar absolute Maximum pressure p max 350 bar absolute Single operating period 10 s Total operating period 300 h Minimum pressure (high-pressure side) 25 bar Rate of pressure change R max 9000 bar/s Pressure p p nom Dp Dt Time t Minimum pressure pump mode (inlet) To prevent damage to the axial piston motor in pump mode, a minimum pressure must be ensured at the service line port (inlet). The minimum required pressure is dependent on the speed of the axial piston unit (see chart below). Minimum pressure (inlet), absolute [bar] Speed n / n nom Definition Nominal pressure p nom The nominal pressure corresponds to the maximum design pressure. Maximum pressure p max The maximum pressure corresponds to the maximum operating pressure within the single operating period. The sum of the single operating periods must not exceed the total operating period. Minimum pressure (high-pressure side) Minimum pressure at the high-pressure side ( or ) which is required in order to prevent damage to the axial piston unit. Rate of pressure change R Maximum permissible rate of pressure rise and reduction during a pressure change over the entire pressure range. Pressure p Single operating period Maximum pressure p max Nominal pressure p nom t 1 t 2 t n Minimum pressure (high-pressure side) Total operating period = t 1 + t t n Time t This diagram is valid only for the optimum viscosity range from n opt = 16 to 36 mm 2 /s. Please contact us if these conditions cannot be satisfied.

6 6/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Technical data Table of values (theoretical values, without efficiency and tolerances; values rounded) Size NG Displacement, V g cm geometric, per revolution Speed maximum 1) n nom rpm Input flow at V g and n nom q V max l/min Torque at V g and Δp = 300 bar T Nm Rotary stiffness of drive shaft c Nm/rad Moment of inertia for rotary group J GR kgm Maximum angular acceleration a rad/s Case volume V L Mass (approx.) m kg Size NG Displacement, geometric, per revolution V g cm Speed maximum 1) n nom rpm 5000 See table below 2) Input flow at V g and n nom q V max l/min Torque at V g and Δp = 300 bar T Nm Rotary stiffness of drive shaft c Nm/rad Moment of inertia for rotary group J GR kgm Maximum angular acceleration a rad/s Case volume V L Mass (approx.) m kg Speed, maximum 1) Size Return pressure ) ) ) ) ) [bar] ) ) ) ) ) ) The values are valid: - for the optimum viscosity range from n opt = 16 to 36 mm 2 /s - for mineral-based operating materials with a specific mass of 0.88 kg/l. 2) Reduced speed through restricted flow via check valve Note Operation above the maximum values or below the minimum values may result in a loss of function, a reduced service life or in the destruction of the axial piston unit. Other permissible limit values, such as speed variation, reduced angular acceleration as a function of the frequency and the permissible angular acceleration at start (lower than the maximum angular acceleration) can be found in data sheet RE Determining the size Input flow q v = V g n 1000 η v [L/min] Speed n = q V 1000 η v [rpm] V g Torque T = Power P = V g Δp η mh 20 π [Nm] 2 π T n = q v Δp η t [kw] V g = Displacement per revolution in cm 3 Δp = Differential pressure in bar n = Speed in rpm η v = Volumetric efficiency η mh = Mechanical-hydraulic efficiency η t = Total efficiency (η t = η v η mh )

7 2FNM Series 61 RE 91007/02.11 osch Rexroth G 7/16 Technical data Permissible radial and axial forces of the drive shaft Size NG 10, 12, 16 10, 12, 16 23, 28, 32 23, 28, Drive shaft Code Z P Maximum radial force 1) at distance a (from shaft collar) a mm W25 ø25 W30 ø30 W30 ø30 F q F q max N a mm Permissible nominal p pressure at V nom perm. bar g max Maximum axial force 2) + +F ax max N Fax F ax max N Permissible axial force per bar operating pressure ±F ax perm /bar N/bar Size NG 56, 63 56, 63 80, 90 80, , , 125 Drive shaft Code Maximum radial force 1) at distance a (from shaft collar) a mm W35 ø35 W40 ø40 W45 ø45 F q F q max N a mm Permissible nominal pressure p at V nom perm. bar g max Maximum axial force 2) + +F ax max N Fax F ax max N Permissible axial force per bar operating pressure ±F ax perm /bar N/bar ) With intermittent operation 2) Maximum permissible axial force during standstill or when the axial piston unit is operating in non-pressurized condition. Note Influence of the direction of the permissible axial force: + F ax max = Increase in service life of bearings F ax max = Reduction in service life of bearings (avoid) Effect of radial force F q on the service life of bearings y selecting a suitable direction of radial force F q, the load on the bearings, caused by the internal rotary group forces can be reduced, thus optimizing the service life of the bearings. Recommended position of mating gear is dependent on direction of rotation. Examples: Gear drive V-belt drive φopt = 70 φopt = 70 Direction of rotation alternating φopt = 45 φopt = 45 "Counter-clockwise" direction of rotation Pressure at port "Clockwise" direction of rotation Pressure at port "Counter-clockwise" direction of rotation Pressure at port

8 8/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Port plate with integrated check valve The motor with the defined direction of rotation is supplied via the inlet port ( or ). s soon as the inlet is cut off and the driven component (e.g. fan wheel) runs from its own flywheel mass, the motor works as a pump. Since the turning motor is now no longer supplied via the inlet, it gets the hydraulic fluid it needs from the return line via the check valve. Schematic Return ( or ) Version with flushing notch When too much heat is developed in the motor (dependent on pressure and speed), more heat can be dissipated by flushing the motor housing. Flushing is done by diverting a flow of hydraulic fluid from the return line into the motor housing through a fixed notch. The flushing flow depends on the size of the notch and the pressure in the return line. The flushing flow mixes with the case drain flow and is then fed through the drain port together with this. The size of the drain port, the flow to be fed off and its viscosity determine the case pressure. This must not exceed the mean continuous case pressure of 3 bar absolute at operating temperature. Inlet ( or ) Schematic Flushing notch Direction of flow Direction of rotation, viewed on drive shaft Clockwise Counterclockwise to to Return ( or ) Inlet ( or ) Maximum flow quantity [l/min] with standard flushing notch Size 10, 12, 16 23, 28, , 63 80, , 125 Return pressure [bar] at 10 mm 2 /s On request 10 12

9 85 2FNM Series 61 RE 91007/02.11 osch Rexroth G 9/16 Dimensions size 10, 12, 16 Port plate 16 Threaded ports, bottom efore finalizing your design, request a binding installation drawing. Dimensions in mm , counter-clockwise rotation clockwise rotation Y Drive shafts Splined shaft DIN 5480 W25x1.25x18x9g 22 M10 x Parallel keyed shaft DIN 6885, S8x7x ø ø28 M10 x ø Ports Designation Port for Standard 5) Size 2) Maximum State pressure [bar] 3), Service line DIN 3852 M22 x 1.5; 14 deep 350 O Drain line DIN 3852 M12 x 1.5; 12 deep 3 X 4) Drain line DIN 3852 M12 x 1.5; 12 deep 3 O 4) 1) Center bore according to DIN 332 (thread according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Depending on installation position, T1 or must be connected (see also page 15). 5) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

10 10/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Dimensions size 23, 28, 32 efore finalizing your design, request a binding installation drawing. Dimensions in mm. Port plate 49 SE flange ports, side and rear Y counter-clockwise rotation ø clockwise rotation Drive shafts Splined shaft DIN 5480 W30x2x14x9g M10 x Parallel keyed shaft DIN 6885, S8x7x ø ø35 M10 x ø Ports Designation Port for Standard Size 2) Maximum State pressure [bar] 3), Service line (standard pressure series) SE J518 4) 1/2 in 350 O Fastening thread / DIN 13 M8 x 1.25; 15 deep O Drain line DIN ) M16 x 1.5; 12 deep 3 X 5) Drain line DIN ) M16 x 1.5; 12 deep 3 O 5) 1) Center bore according to DIN 332 (threads according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Only dimensions according to SE J518. metric fastening thread is a deviation from standard. 5) Depending on installation position, T1 or must be connected (see also page 15). 6) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

11 2FNM Series 61 RE 91007/02.11 osch Rexroth G 11/16 Dimensions size 45 Port plate 16 Threaded ports, bottom efore finalizing your design, request a binding installation drawing. Dimensions in mm Y ø counter-clockwise rotation Drive shafts Z M12 x 1.75 Splined shaft DIN 5480 W30x2x14x9g P Parallel keyed shaft DIN 6885, S8x7x ø ø35 M12 x ø Ports Designation Port for Standard 5) Size 2) Maximum State pressure [bar] 3), Service line DIN 3852 M26 x 1.5; 20 deep 350 O Drain line DIN 3852 M18 x 1.5; 12 deep 3 X 4) Drain line DIN 3852 M18 x 1.5; 12 deep 3 O 4) 1) Center bore according to DIN 332 (threads according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Depending on installation position, T1 or must be connected (see also page 15). 5) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

12 12/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Dimensions size 56, 63 Port plate 48 Threaded ports, side and rear efore finalizing your design, request a binding installation drawing. Dimensions in mm Y ø ø counter-clockwise rotation clockwise rotation 147 Drive shafts Splined shaft DIN 5480 W35x2x16x9g M12 x Parallel keyed shaft DIN 6885, S10x8x ø ø40 M12 x ø Ports Designation Port for Standard 5) Size 2) Maximum State pressure [bar] 3), Service line DIN 3852 M33 x 2; 20 deep 350 O Drain line DIN 3852 M18 x 1.5; 12 deep 3 X 4) Drain line DIN 3852 M18 x 1.5; 12 deep 3 O 4) 1) Center bore according to DIN 332 (threads according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Depending on installation position, T1 or must be connected (see also page 15). 5) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

13 2FNM Series 61 RE 91007/02.11 osch Rexroth G 13/16 Dimensions size 80, 90 Port plate 34 SE flange ports, bottom efore finalizing your design, request a binding installation drawing. Dimensions in mm Y ø counter-clockwise rotation ø Drive shafts Splined shaft, DIN 5480 W40x2x18x9g M16 x ø45 Parallel keyed shaft DIN 6885, S12x8x ø M16 x ø45 Ports Designation Port for Standard Size 2) Maximum State pressure [bar] 3), Service line (standard pressure series) SE J518 4) 1 in 350 O Fastening thread / DIN 13 M10 x 1.5; 17 deep O Drain line DIN ) M18 x 1.5; 12 deep 3 X 5) Drain line DIN ) M18 x 1.5; 12 deep 3 O 5) 1) Center bore according to DIN 332 (threads according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Only dimensions according to SE J518. metric fastening thread is a deviation from standard. 5) Depending on installation position, T1 or must be connected (see also page 15). 6) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

14 14/16 osch Rexroth G 2FNM Series 61 RE 91007/02.11 Dimensions size 107, 125 Port plate 34 SE flange ports, bottom efore finalizing your design, request a binding installation drawing. Dimensions in mm Y ø ø25 counter-clockwise rotation clockwise rotation 26.2 Drive shafts Splined shaft DIN 5480 W45x2x21x9g M16 x ø50 Parallel keyed shaft DIN 6885, S14x9x ø M16 x ø50 Ports Designation Port for Standard Size 2) Maximum State pressure [bar] 3), Service line (standard pressure series) SE J518 4) 1 in 350 O Fastening thread / DIN 13 M10 x 1.5; 17 deep O Drain line DIN ) M18 x 1.5; 12 deep 3 X 5) Drain line DIN ) M18 x 1.5; 12 deep 3 O 5) 1) Center bore according to DIN 332 (threads according to DIN 13) 2) Observe the general instructions on page 16 for the maximum tightening torques. 3) Momentary pressure spikes may occur depending on the application. Keep this in mind when selecting measuring devices and fittings. 4) Only dimensions according to SE J518. metric fastening thread is a deviation from standard. 5) Depending on installation position, T1 or must be connected (see also page 15). 6) The spot face can be deeper than specified in the appropriate standard. O = Must be connected (plugged on delivered) X = Plugged (in normal operation)

15 2FNM Series 61 RE 91007/02.11 osch Rexroth G 15/16 Installation instructions General During commissioning and operation, the axial piston unit must be filled with hydraulic fluid and air bled. This must also observed following a relatively long standstill as the axial piston unit may drain back to the reservoir via the hydraulic lines. Particularly in the installation position "drive shaft upwards" filling and air bleeding must be carried out completely as there is, for example, a danger of dry running. The case drain fluid in the motor housing must be directed to the reservoir via the highest available drain port (, ). To achieve favorable noise values, decouple all connecting lines using elastic elements and avoid above-reservoir installation. In all operating conditions, the drain line must flow into the reservoir below the minimum fluid level. Installation position See the following examples 1 to 8. Further installation positions are available upon request. Recommended installation position: 1 and 2. Instructions In installation position "shaft upwards", an air bleed port R is necessary (please state in plain language when ordering - special version). elow-reservoir installation (standard) elow-reservoir installation is when the axial piston unit is installed outside of the reservoir below the minimum fluid level. 1 2 bove-reservoir installation bove-reservoir installation is when the axial piston unit is installed above the minimum fluid level of the reservoir. Recommendation for installation position 8 (drive shaft upward): check valve in the drain line (cracking pressure 0.5 bar) can prevent draining of the motor housing. 5 6 L L bar L 1 R Installation position ir bleed Filling 5 ( L 1) 6 ( L 1) 7 ( L 1) 8 R (L 1 ) ( L 1) L 1 L 1 Filling / air bleed 3 4 R, ir bleed port (special version) Drain port Minimum required immersion depth (200 mm) Minimum required spacing to reservoir base (100 mm) R Installation position ir bleed Filling R

16 16/16 osch Rexroth G 2FNM Series 2FM 61 RE 91001/ /02.11 General instructions The motor 2FNM is designed to be used in open circuit. The project planning, installation and commissioning of the axial piston unit requires the involvement of qualified personnel. efore using the axial piston unit, please read the corresponding instruction manual completely and thoroughly. If necessary, these can be requested from Rexroth. During and shortly after operation, there is a risk of burns on the axial piston unit. Take appropriate safety measures (e.g. by wearing protective clothing). Depending on the operating conditions of the axial piston unit (operating pressure, fluid temperature), the characteristic may shift. Service line ports: --The ports and fastening threads are designed for the specified maximum pressure. The machine or system manufacturer must ensure that the connecting elements and lines correspond to the specified operating conditions (pressure, flow, hydraulic fluid, temperature) with the necessary safety factors. --The service line ports and function ports are only designed to accommodate hydraulic lines. The data and notes contained herein must be adhered to. The product is not approved as a component for the safety concept of a general machine according to DIN EN ISO The following tightening torques apply: --Fittings: Observe the manufacturer's instructions regarding the tightening torques of the fittings used. --Mounting bolts: For mounting bolts with metric ISO thread according to DIN 13, we recommend checking the tightening torque in individual cases in accordance with VDI Female threads in the axial piston unit: The maximum permissible tightening torques M G max are maximum values of the female threads and must not be exceeded. For values, see the following table. --Threaded plugs: For the metallic threaded plugs supplied with the axial piston unit, the required tightening torques of threaded plugs M V apply. For values, see the following table. Ports Standard Size of thread Maximum permissible tightening torque of the female threads M G max Required tightening torque of the threaded plugs M V WF size hexagon socket of the threaded plugs DIN 3852 M12 x Nm 25 Nm 6 mm M14 x Nm 35 Nm 6 mm M16 x Nm 50 Nm 8 mm M18 x Nm 60 Nm 8 mm M26 x Nm 120 Nm 12 mm M33 x Nm 225 Nm 17 mm osch Rexroth G Hydraulics xial Piston Units Glockeraustraße Elchingen, Germany Phone Fax info.brm-ak@boschrexroth.de This document, as well as the data, specifications and other information set forth in it, are the exclusive property of osch Rexroth G. It may not be reproduced or given to third parties without its consent. The data specified above only serve to describe the product. No statements concerning a certain condition or suitability for a certain application can be derived from our information. The information given does not release the user from the obligation of own judgment and verification. It must be remembered that our products are subject to a natural process of wear and aging. Subject to change.