dhi constant volume valve pn 402151 installation instructions Manuel D’Utilisation

 

Document 560076 

050216 

4765 East Beautiful Lane 

Phoenix  AZ  85044-5318 

USA 

 

Tel 602.431.9100

Fax 602.431.9559

dhi@dhinstruments.com

www.dhinstruments.com

 

 

Installation Instructions 

1 

402177 

Valve, constant volume 

2 

103686 

DH500 F x DH200-2 M adaptor  

1 

102159 

10-32 UNF M x 1/8 in. barb adaptor 

1 

103426 

10-32 UNF M x 1/8 in. quick connector 

1 560076 

Instruction 

Sheet 

The constant volume valve is a pneumatically 
actuated needle valve with a return line connecting the 
inlet to a coaxial compensator. Needle displacement is 
matched by an equal and opposite volume 
displacement on the compensator. 

Port A connection: DH200-2* 
Port B connection: DH200-2* 
Drive air connection (to open valve): 10-32 UNF F 
Operating fluid: Oil 
Maximum line pressure: 200 MPa (30 000 psi) 
Maximum differential pressure on Port A or Port B: 
200 MPa (30 000 psi) 
Drive air pressure required to open valve: 
   - With zero differential: <500 kPa (70 psi) 
   - With 200 MPa differential, Port A:<400 kPa (60 psi) 
   - With 200 MPa differential, Port B: 750 kPa (110 psi) 
Maximum drive air pressure: 850 kPa (125 psi) 

Typical change in volume on port A or B when the 
valve is opened or closed: <0.2 mm

3

 

* DH200-2 is equivalent to HIP HF2 for 1/8 in. OD, coned and 
threaded stainless steel tube 

  Connect the valve between the two pressure 

systems to be isolated using ports A and B.  Use 
the DH200-2 M x DH500 F adaptors supplied if 
desired.  To install the adaptors, remove the 
DH200-2 glands and collars from the DH200-2 
connections. 

  Connect a drive air supply to the drive air connection.  

Use the 10-32 UNF M x barb adaptor or 10-32 UNF 
M x quick connector supplied if desired. 

 

 

Figure 1. Constant volume valve cutaway view 

•  To open the valve, supply drive air pressure to the 

drive air port. To close the valve, vent the drive air 
pressure. 

•  To reduce the opening/closing speed of the valve, 

put an adjustable restriction or fixed orifice on the 
drive air supply and exhaust.  This can be useful 
to reduce pressure perturbations from the valve 
opening/closing. 

•  To automate opening and closing of the valve, use 

a three way, low pressure solenoid valve to control 
drive air/vent supply to the valve actuator. 

•  To reduce the relative effect of the small change in 

volume due to deformation of the valve seat after the 
valve closes, add volume to the pressurized system. 

•  After the valve closes, a small volume change 

occurs from elastic deformation of the seat.  The 
deformation can be reduced by special shimming 
to reduce the force of the needle on the seat when 
the valve is closed, but the maximum differential 
pressure on port A is reduced.