►Products > Series SV-Pneumatic Rack and Pinion Actuator
 
     

 
 
 		  


 

  • Rack and Pinion Design
  • The standard actuator configuration has hard anodized aluminum body and epoxy coated caps. External protection; resistance to corrosion of 500 hours in salty atmosphere, according to ASTM B 117-73
  • Inside Surface finish( Ra 0.4-6.6um) to minimize friction and to maximize the life of actuator.
  • Standard Applications for temperature ranges from -4ºF    (-20ºC) to +180ºF (85ºC)
  • Special options for extreme temperatures ( upon request)SimCo Valves-AIR Series Pneumatic Actuators
  • Piston bearing made of material with low friction coefficient (LAT LUB) to avoid metal to metal contact, easily replaceable for maintenance.
  • Double lower drilling, for valve mounting, and centering, according to ISO 5211/DIN 3337 standards.
  • Top drilling for fastening of the accessories and upper shaft end according to NAMUR standards.
  • Direct mounted solenoid connections according to NAMUR standards
  • Independent travel stop adjustment of 4 º in both directions.
  • Lower female shaft key, according to ISO 5211/ DIN 3337 standards, for assembly on valves with star shaft.
  • Same body and end cap for double acting and Spring return.
  • Air supply: dry or lubricated filtered compressed air; pressure: min. 14.5 PSI-145 PSI
  • The Lubrication carried out by the manufacturer is guaranteed for min 1,000.000 operations.
  • Running test and 100% seal test carried out with electronic equipment and certification of each product.
  • Position indicator.
 
 
Part No. QTY. Description

Materials of Construction
Body Aluminum alloy, extruded according to ASTM 6063, anodized according to UNI 4522
End Cap Die-Cast in aluminum alloy ASTM B179, painted with epoxy-polyester powder.
Pistons Die-Cast in aluminum alloy ASTM B179.
Pinion Nickel-plated steel.
Pinion Bearings Acetal Resin (LAT LUB 731 320T) + 20% PTFE.
Screws Stainless steel AISI 304
Springs Precompressed cartridge, painted with epoxy powder.
Seals Nitrile rubber NBR (VITON or EPDM on request).
Standard Grease MoS2.
Optional Grease Molykote.

SimCo Valves-AIR Series Pneumatic Actuators - Parts and Identification
1 1 Body
2 2 Piston
3 2 End Cap
4 1 Pinion
5 2 Piston Pilot Key
6 1 Pinion Lower O-Ring
7 1 Pinion Upper O-Ring
10 1 Retaining Ring
11 6-12 Spring Cartridge
12 2 Piston O-Ring
13 2 Piston Bearing
14 2 End Cap Gasket
15 1 Name Plate
16 8 End Cap Screw
17 4 Nut
18 4 Washer
19 4 O-Ring
21 2 Travel Stop
23 1 Pinion Thrust Washer
24 1 Thrust Bearing
25 1 Lower Pinion Bearing
26 1 Upper Pinion Bearing
27 2 Piston Bearing
28   Piston Screw
 

Optional Corrosion Protections

Coating with Chemical Nickel Having High Phosphorous Content
Nickel Deposits without electricity are produced by the chemical reaction of nickel in metallic substrate, without using electricity. Dead holes, threads, grooves, recesses or inside surfaces receive the same plating quantity as the sharp angles, the corners or the flat surface(20-30 um). The standard degree is approximately 45-55 Rockwell C and offers a good resistance to corrosion in salty fog. Please take care not to damage the surface by scraping, since this exposes the basic material to corrosion. ( on request, the pistons may also be nickel coated.)   

Strong Anodized Protection
The electrical process produces a thick anodized coating up to 50 microns. The resulting part resists corrosion from dipping and SVrays of sodium and chlorine and also corrosive cracking stress. The oxide coating is perfectly adherent and will not chip, even after sudden temperature changes or at temperatures equal to aluminum melting point. Aluminum oxide is one of the hardest known materials: 45-65 Rockwell C.

Epoxy-Polyester Coating
Epoxy coating is a deposit of powders on clean and sandblasted pieces. The chemical process is easily kept under control after coating, the pieces must be subjected to heat treatment. Epoxy painting of actuators is advised where environment is strongly aggressive. With a normal thickness of 200?250 microns of epoxy coating, resistance to salty fog exceeds 1,000 hours. With the exception of certain solvents, epoxy coating must not be scratched. ( Springs have standard coating.)
   

Actuation Sizing Guide

The seat material used, media, temperature, frequency of operation and criticality of the valve's operation are all important factors in calculating the actuation needs of a given valve. The information provided below should be considered as a guide only and must be adjusted according to experience and judgment. Proper actuator selection is required to prevent valve or process equipment damage as well as proper valve operation.

In general, we can say that valve torque results from the friction between the ball and seats as well as the stem and stem seals.
Valve Torque

The torque requirements of SimCo Ball Valves will vary depending on several factors.

  • Seat design and material

SimCo seats are designed to ensure consistent sealing and low torque. The seat friction force depends on the seat material and the applicable service factor multipliers shown in the chart below

  • Stem Seal

Torque results from the stem contact with stem seals. Packing materials affect torque. Stem seal torque is a high percentage of overall torque especially in small valve sizes.
Service Conditions 
  • Differential Pressure                   Minimum and maximum pressures
  • Frequency of Operation              Stuck valve torque
  • Media Influence                            Slurries, dry gases, oils
  • Temperatures                               Minimum and maximums
  • Cycle Time                                     Line hammer, process requirements
  • Instrument Air Supply                 Peak demand pressure availability
Media and Service Factors
 To establish minimum torque requirements, multiply valve torque by following application media and service factors.
 
   
   
Media Factors Multiplier
Clean particle free, non-lubricating (water, alcohol or solvents) 1.00
Clean particle free, lubricating oil .80
Slurries or heavily corroded and contaminated systems 1.30 to 2.00
Gas or saturated steam, clean and wet 1.00
Gas or superheated steam, clean and dry 1.30
Gas, dirty unfiltered e.g. natural gas, Chlorine 1.20 to 1.50
Service Multiplier
Simple On and Off Operations 1.00
Throttling 1.20
Positioner Control 1.50
Once per day session 1.20
Once every two days or more or plant critical 1.50
 
Service Multiplier
Simple On and Off Operations 1.00
Throttling 1.20
Positioner Control 1.50
Once per day session 1.20
Once every two days or more or plant critical 1.50
 
   
Ball Valve

Ball valve construction concept is based essentially on a polished ball (including a through port) contained in two seats (upstream and downstream). The ball rotation allows the flow or stops the flow through the valve. Differential pressure between upstream and downstream pressure forces the ball against the downstream seat (floating ball). In this case, the valve torque is generated by the friction between ball and seat and also between stem and packing. As shown in the diagram to the right the highest torque point is when, in presence of pressure, the valve is in the closed position, and passes to the open position (breakaway torque).		 SimCo-AIR Series Pneumatic Actuators
Butterfly Valve
Butterfly valve construction concept is based essentially on a disc fixed on an axis, which in the closed position, is completely contained by the seat. The open position is obtained when, with a rotation, the disc (through its stem) becomes parallel to the flow. On the contrary, the closed position is obtained when the disc is perpendicular to the flow. In the case of the butterfly valve, the torque is generated by the friction between the disc and the seat, by the stem packing and also by the differential pressure that forces on the disc. The highest torque point, as shown in the diagram, is in the closed position, and only after a small rotation it is considerably reduced.
 		 SimCo-AIR Series Pneumatic Actuators
Plug Valve

Plug valve construction concept is based essentially on a male (plug) contained in a female cone (seat). The plug provides a through port in one direction and with its rotation into the seat the opening and closure of the valve is obtained. The torque is usually not influenced by the flow pressure, but is generated essentially by the friction between the seat and the plug, during the opening and closing cycle. As shown in the diagram to the right, the highest torque point is in the closed position and remains high for the rest of the operation, because the torque is not influenced by pressure.		 Sharpe Valves SP-AIR Series Pneumatic Actuators
Double Acting Actuator (DA)

In the double acting actuators, the control pinion rotation and its reversal are obtained by reversing the supply to the two input ports. The output torques obtainable mainly depend on the cylinder diameter and the supply pressure; by increasing on or both factors the available torque also increases. The friction should usually be negligible. As shown in diagram A, the torque of a DA actuator is constant throughout the entire rotation and relevant reversal. The advised safety factor, in addition to the valve maneuver torque, is approximately 20%.

*Select the actuator size whose torque output at given pressure exceeds the valve torque and application factor.

 Simco-AIR Series Pneumatic Actuators

 

  

SimCo-AIR Series Pneumatic Actuators - Operation

  
   
Reverse Rotation
Upon request, the pistons can be inverted in order to obtain a clockwise rotation when the air pressure is applied to Port A. Other types of assembly are possible: for any information, please contact SimCo Valves.
Quick Operation Actuators
Upon request, SV-AIR Series actuators can be specially prepared for fast response operations.
 
   

Spring Return Actuator (SR)
In these types of actuators, which utilize springs for reversing the rotation of the control pinion, the output torque depends not only on the cylinder diameter and the supply pressure, but also on the presence of the springs, which should be compressed to guarantee the return. As shown in diagram C, the available torque at 0° progressively reduces during the rotation due to the springs' compression. On the contrary, as shown in Diagram D, the torque starting from the 90° position constantly decreases until 0° because of spring extension. Owing to the higher friction present, the safety coefficient advised in this case is approximately 25%.

*Select the actuator whose torque output at 0° and 90° at a given air pressure exceeds the valve torque.
 
Upon request, the pistons can be inverted in order to obtain a clockwise rotation when the air pressure is applied to Port A. Other types of assembly are possible: for any information, please contact SimCo.
 
Quick Operation Actuators
Upon request, SV-AIR Series actuators can be Specially prepared for fast response operations.

  
Installation
  • Make sure that the actuator, when fitted on the valve, is well aligned with the valve stem. When actuator is directly fitted with bracket and coupling, all parts must be precisely machined.
  • In Spring return applications, the exhaust air port must be very well vented.
  • Accessories, if any, must be mounted in a proper manner to allow unobstructed operation of the actuator.


 
Maintenance
  1. Remove the end cap screws of the end cap.
  2. Take off the end cap.
  3. Turn the pinion in clockwise direction so that the pistons come out of the body.
  4. Remove the retaining ring.
  5. Take the pinion out from the lower part of the body by simply pressing it with your fingers.
  6. Replace the following parts:
    On the pistons:
    2 O-Rings; 2 bearings; 2 keys; 2 piston bearings; 2 O-Rings.
    On the heads:
    2 gaskets; 2 O-Rings.
    On the pinion:
    2 O-Rings; 1 bearing; 1 lower bearing; 1 upper bearing; 1 pinion thrust washer.
 
 

Dimensions (inches)

POSITION

ACTUATOR TYPE
SVO32 SV050 SVO63 SV075 SVO85 SV100 SV115 SV125 SV145 SV160 SV200 SV270
a 4.61 5.43 6.12 8.27 8.97 11.04 12.2 14.25 15.35 18.19 22.63 26.97
b 1.77 2.63 3.27 3.94 4.33 4.92 5.60 6.10 6.89 7.72 9.45 13.07
c 1.77 2.68 3.38 3.70 4.90 4.72 5.27 5.55 6.41 6.93 8.66 13.86
d --- --- --- 4.13 4.13 4.13 5.47 5.47 5.47 5.47 5.47 ---
e --- --- --- 0.87 0.87 0.87 0.87 0.87 0.87 0.87 0.87 ---
f 1.97 3.15 3.15 3.15 3.15 3.15 35.12 5.12 5.12 5.12 5.12 5.12
g 0.98 1.18 1.18 1.18 1.18 1.18 1.18 1.18 1.18 1.18 1.18 1.18
h --- 1.18 1.38 1.38 1.57 2.16 2.16 2.16 2.75 2.95 3.94 4.09
I 0.39 0.51 0.63 0.79 0.79 0.98 0.98 1.18 1.18 1.18 1.45 1.45
l 0.88 1.32 1.50 1.67 1.93 2.16 2.50 2.74 3.14 3.46 4.33 6.53
m 0.88 1.63 1.89 2.03 2.16 2.56 2.77 2.81 3.26 3.46 4.33 6.53
T-din 259 1/8" 1/8" 1/4" 1/4" 1/4" 1/4" 1/4" 1/4" 1/4" 1/4" 1/4" 1/2"
n 0.31 0.31 0.31 0.55 0.55 0.55 1.06 1.06 1.06 1.06 1.26 2.16
o 0.47 0.47 0.47 0.71 0.71 0.71 1.42 1.42 1.42 1.42 1.65 3.15
p 0.79 0.79 0.79 0.79 0.79 0.79 1.18 1.18 1.18 1.97 1.97 1.97
r 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 0.47 ---
s 0.63 0.63 0.63 0.63 0.63 0.63 0.63 0.63 0.63 0.63 0.63 ---
diam 0 1.42 1.65 1.97 1.97/2.76 1.97/2.76 2.76/4.02 2.76/4.02 2.76/4.02 2.76/4.02 4.02/4.92 5.51 5.51
Q 0.35 0.43 0.55 0.67 0.67 0.87 0.87 1.06 1.06 1.06 1.42 1.42
w M5 M5 M6 M6-M8 M6-M8 M8-M10 M8-M10 M8-M10 M10-M12 M10-M12 M16 M16
ISO 5211 F03