The throttle valve has {TAIL ~ at least two variable orifices} and a compensation chamber between {HEAD ~ the variable orifices} 
The throttle valve has { TAIL ~ at least two variable orifices } and a compensation chamber between { HEAD ~ the variable orifices }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD