  We develop a new theory for associating fluids with multiple association
sites. The theory accounts for small bond angle effects such as steric
hindrance, ring formation and double bonding. The theory is validated against
monte carlo simulations for the case of a fluid of patchy colloid particles
with three patches and is found to be very accurate. Once validated, the theory
is applied to study the phase diagram of a fluid composed of three patch
colloids. It is found that bond angle has a significant effect on the phase
diagram and the very existence of a liquid - vapor transition.
