Specifications, How v-7 valves work – Liquid Controls V-7 Valves User Manual

Page 3

Specifications

How V-7 Valves Work

Inside the valve housing, a cylindrical bore connects the

valve inlet and outlet. Contained within the bore is a

piston assembly. Measured liquid exiting the meter outlet

is blocked from entering the valve inlet by the piston and

seal.

As the meter operator shifts the handle to the open

position, a mechanical linkage connecting the valve to

the preset counter trip ring causes a latch to engage and

hold the valve open allowing liquid to flow.

In the open position, the valve handle assembly

compresses the piston spring and pulls the piston shaft

and the piston away from the valve inlet. As the piston is

pulled away, it disconnects from the inlet seal, allowing

liquid to flow.

In most metering applications, closing the valve is a two-

stage process. At a predetermined dwell period, the

preset counter, while counting down to “0”, releases a

latch mechanism, allowing the valve linkage to close to

approximately 10% of full flow. This initial closing causes

the piston inside the valve to slide toward the inlet,

restricting product flow.

As liquid is blocked by the piston, some product passes

through the dashpot washer bleed holes, creating the

hydraulic balance feature of V-7 Valves that allows the

valve to close slowly and smoothly. The dwell period

prevents hydraulic shock while permitting the preset

counter to register the remaining flow.

As the preset counter reaches “0”, the preset counter trip

ring disengages from the dwell position to the fully closed

position. This action releases the valve handle and relaxes

the piston spring, permitting the piston to contact the inlet

ring seal and complete its closure, stopping product flow.

This process is illustrated in Figure 2.

Model

Companion
Flanges

Application
Class*

A2621

1½" & 2"

1, 2, 14

A2623

1½" & 2"

1, 2, 3, 4, 14, 15,
16, 30

A2631

1½" & 2"

1, 3, 14, 15

A2651

1½" & 2"

3, 4, 14, 15, 16

A2652

1½" & 2"

1, 2, 16, 20

A2655

1½" & 2"

1, 30

A2684

1½" & 2"

A2690

1½" & 2"

A2693

1½" & 2"

A2670

1½" & 2"

7, 37

A2671

1½" & 2"

7, 27

A2672

1½" & 2"

7, 27, 37

A2681

1½" & 2"

A2682

1½" & 2"

150 PSI (10.3 BAR)

150 PSI (10.3 BAR)
150 PSI (10.3 BAR)
150 PSI (10.3 BAR)
150 PSI (10.3 BAR)

150 PSI
(10.3 BAR)
150 PSI (10.3 BAR)

150 PSI (10.3 BAR)

V-7 (A2600 Series)
Used with M-5, M-7 & M-10 Meters

Body & Seal Material

Cast Iron with Viton Seal
Stainless Steel with Viton Seal
Stainless Steel with Teflon Seal

Brass with Teflon Seal
Cast Iron with Viton Seal
Cast Iron with Teflon Seal

Aluminum with Viton & Teflon Seal
Brass with Viton Seal
Brass with Viton Seal

Aluminum with Viton Seal

Aluminum with Teflon Seal

Aluminum with Viton Seal
Aluminum with Viton Seal
Aluminum with Buna N Seal

Working
Pressure

Figure 2: Valve Operation