Control Valve Actuator Sizing and Valve Action Selection The materials included in this compilation are for the use of Dwyer Instruments, Inc. potential customers and current employees as a resource only. They may not be reproduced, published, or transmitted electronically for commercial purposes. Furthermore, the Company’s name, likeness, product names, and logos, included within these compilations may not be used without specific, written prior permission from Dwyer Instruments, Inc. ©Copyright 2015 Dwyer Instruments, Inc.
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Control Valve Actuator Sizing and Valve Action Selection
T h e m a t e r i a l s i n c l u d e d i n t h i s c o m p i l a t i o n a r e f o r t h e u s e o f D w y e r I n s t r u m e n t s , I n c . p o t e n t i a l c u s t o m e r s a n d c u r r e n t e m p l o y e e s a s a r e s o u r c e o n l y . T h e y m a y n o t b e r e p r o d u c e d , p u b l i s h e d , o r t r a n s m i t t e d e l e c t r o n i c a l l y f o r c o m m e r c i a l p u r p o s e s . F u r t h e r m o r e , t h e C o m p a n y ’ s n a m e , l i k e n e s s ,
p r o d u c t n a m e s , a n d l o g o s , i n c l u d e d w i t h i n t h e s e c o m p i l a t i o n s m a y n o t b e u s e d w i t h o u t s p e c i fi c , w r i t t e n p r i o r p e r m i s s i o n f r o m D w y e r I n s t r u m e n t s , I n c .
© C o p y r i g h t 2 0 1 5 D w y e r I n s t r u m e n t s , I n c .
Control Valve ActuatorO v e r v i e w
D w y e r ’ s H I - F l o w S e r i e s c o n t r o l v a l v e s h a v e p n e u m a t i c a c t u a t o r s t h a t m o d u l a t e t h e v a l v e f o r fl o w c o n t r o l
T h e o p e n i n g , c l o s i n g a n d t h r o t t l i n g o f t h e v a l v e p l u g i s a c c o m p l i s h e d b y v a r y i n g t h e a i r p r e s s u r e t o t h e d i a p h r a g m i n t h e a c t u a t o r
Ty p i c a l l y t h e c o n t r o l p r e s s u r e s i g n a l i s 3 t o 1 5 p s i g
T h e r e a r e t w o t y p e s o f a c t u a t o r s A i r - To - L o w e r A i r - To - R a i s e
Control Valve ActuatorO v e r v i e w
I n A i r -To - L o w e r a c t u a t o r s , a s t h e p r e s s u r e s i g n a l i s i n c r e a s e d , t h e d i a p h r a g m p u s h e s d o w n , m o v i n g t h e s t e m a n d p l u g d o w n , a n d c o m p r e s s i n g t h e r a n g e s p r i n g
A s t h e p r e s s u r e s i g n a l i s d e c r e a s e d , t h e r a n g e s p r i n g p u s h e s t h e d i a p h r a g m u p , m o v i n g t h e v a l v e s t e m a n d p l u g u p
Control Valve ActuatorO v e r v i e w
I n A i r -To - R a i s e a c t u a t o r s , a s t h e p r e s s u r e s i g n a l i s i n c r e a s e d , t h e d i a p h r a g m p u s h e s u p , m o v i n g t h e s t e m a n d p l u g u p , a n d c o m p r e s s i n g t h e r a n g e s p r i n g
A s t h e p r e s s u r e s i g n a l i s d e c r e a s e d , t h e r a n g e s p r i n g p u s h e s t h e d i a p h r a g m d o w n , m o v i n g t h e v a l v e s t e m a n d p l u g d o w n a s w e l l
Control Valve BodyO v e r v i e w
T h e H i - F l o w c o n t r o l v a l v e s e r i e s o ff e r s t w o t y p e s o f v a l v e b o d i e s , P u s h -To - C l o s e , a n d P u s h -To - O p e n
I n P u s h -To - C l o s e , t h e v a l v e s t e m m o v e s d o w n w a r d , p u s h i n g t h e v a l v e p l u g c l o s e r t o t h e s e a t i n t h e v a l v e b o d y
T h i s m o v e m e n t d e c r e a s e s t h e fl o w t h r o u g h t h e v a l v e
Control Valve BodyO v e r v i e w
I n P u s h -To - O p e n , t h e v a l v e s t e m m o v e s d o w n w a r d , p u s h i n g t h e v a l v e p l u g a w a y f r o m t h e s e a t i n t h e v a l v e b o d y
T h i s m o v e m e n t i n c r e a s e s t h e fl o w t h r o u g h t h e v a l v e
Control Valve ActionO v e r v i e w
W i t h t h e c h o i c e o f a c t u a t o r s , A i r -To - R a i s e o r A i r -To - L o w e r ; a n d v a l v e b o d i e s , P u s h -To - C l o s e o r P u s h -To - O p e n ; t h e p r o p e r a c t i o n o f t h e v a l v e c a n b e s e l e c t e d f o r t h e a p p l i c a t i o n , d i r e c t a c t i n g o r r e v e r s e a c t i n g
C o n s i d e r a t i o n s h o u l d a l s o b e t a k e n f o r t h e f a i l p o s i t i o n o f t h e v a l v e , w h i c h i s w h a t t h e v a l v e w i l l d o o n l o s s o f t h e c o n t r o l s i g n a l a i r
Control ValveO v e r v i e w
A P u s h -To - C l o s e v a l v e b o d y w i t h a n a i r - t o - r a i s e a c t u a t o r w i l l h a v e a v a l v e a c t i o n o f a i r - t o - o p e n a n d s p r i n g c l o s e d
T h i s i s a n o r m a l l y c l o s e d v a l v e a n d i s r e v e r s e a c t i n g
Control ValveO v e r v i e w
A P u s h -To - O p e n v a l v e b o d y w i t h a n a i r - t o - l o w e r a c t u a t o r w i l l h a v e a v a l v e a c t i o n o f a i r - t o - o p e n a n d s p r i n g c l o s e d
T h i s i s a n o r m a l l y c l o s e d v a l v e a n d i s r e v e r s e a c t i n g
I t h a s t h e a d d e d s a f e t y f a c t o r t h a t t h e u p s t r e a m p r e s s u r e w i l l c l o s e t h e v a l v e o n c o n t r o l s i g n a l a i r l o s s
Control ValveO v e r v i e w
A P u s h -To - o p e n v a l v e b o d y w i t h a n a i r - t o - r a i s e a c t u a t o r w i l l h a v e a v a l v e a c t i o n o f a i r - t o - c l o s e , s p r i n g o p e n
T h i s i s a n o r m a l l y o p e n v a l v e a n d i s d i r e c t a c t i n g
Control ValveO v e r v i e w
A P u s h -To - c l o s e v a l v e b o d y w i t h a n a i r - t o - l o w e r a c t u a t o r w i l l h a v e a v a l v e a c t i o n o f a i r - t o - c l o s e , s p r i n g o p e n
T h i s i s a n o r m a l l y o p e n v a l v e a n d i s d i r e c t a c t i n g
I t h a s t h e a d d e d s a f e t y f a c t o r t h a t t h e u p s t r e a m p r e s s u r e w i l l o p e n t h e v a l v e o n c o n t r o l s i g n a l a i r l o s s
Actuator SizingO v e r v i e w
T h e a c t u a t o r m u s t b e s i z e d t o b e l a r g e e n o u g h t o s h u t - o ff t h e v a l v e a g a i n s t s y s t e m p r e s s u r e o n t h e v a l v e p l u g
T h e H i - F l o w l i n e c o m e s i n t h r e e a c t u a t o r s i z e s w i t h a v a r i e t y o f r a n g e s p r i n g s i z e s a c c o r d i n g t o t h e s h u t - o ff p r e s s u r e n e e d e d
Va l v e s i z i n g c h a r t s o n t h e D w y e r w e b s i t e a n d i n t h e D w y e r c a t a l o g s h o w t h e m a x i m u m s h u t - o ff p r e s s u r e f o r e a c h s i z e v a l v e w i t h e a c h s i z e a c t u a t o r
Actuator SizingO v e r v i e w
W h e n o r d e r i n g a v a l v e , t h e m a x i m u m u p s t r e a m p r e s s u r e w i l l n e e d t o b e s p e c i fi e d a n d t h e s p r i n g s i z e i s a u t o m a t i c a l l y c h o s e n a c c o r d i n g l y
T h e r a n g e s p r i n g h a s a n o p e r a t i n g r a n g e o f s h u t - o ff p r e s s u r e s t h a t i t w i l l o p e r a t e w i t h , a n d t h e a c t u a t o r h a s a n a d j u s t m e n t f o r fi e l d c a l i b r a t i o n f o r s h u t - o ff p r e s s u r e w i t h i n t h a t s p r i n g r a n g e
I t i s b e s t t o a d j u s t t h e v a l v e i n t h e a p p l i c a t i o n s o t h a t i t o p e r a t e s a t t h e p a r t i c u l a r s h u t - o ff p r e s s u r e i n t h e a p p l i c a t i o n l i n e
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