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